fix badge

* add gh-dash config
* fix linting errors

.gh-dash.yml

@@ -0,0 +1,96 @@
+prSections:
+  - title: Responsible PRs
+    filters: repo:tlinden/rpnc is:open NOT dependabot
+    layout:
+      repoName:
+        hidden: true
+
+  - title: Responsible Dependabot PRs
+    filters: repo:tlinden/rpnc is:open dependabot
+    layout:
+      repoName:
+        hidden: true
+
+issuesSections:
+  - title: Responsible Issues
+    filters: is:open repo:tlinden/rpnc -author:@me
+    layout:
+      repoName:
+        hidden: true
+
+  - title: Note-to-Self Issues
+    filters: is:open repo:tlinden/rpnc author:@me
+    layout:
+      creator:
+        hidden: true
+      repoName:
+        hidden: true
+
+defaults:
+  preview:
+    open: false
+    width: 100
+
+keybindings:
+  universal:
+    - key: "shift+down"
+      builtin: pageDown
+    - key: "shift+up"
+      builtin: pageUp
+  prs:
+    - key: g
+      name: gitu
+      command: >
+        cd {{.RepoPath}} && /home/scip/bin/gitu
+    - key: M
+      name: squash-merge
+      command: gh pr merge --rebase --squash --admin --repo {{.RepoName}} {{.PrNumber}}
+    - key: i
+      name: show ci checks
+      command: gh pr checks --repo {{.RepoName}} {{.PrNumber}} | glow -p
+    - key: e
+      name: edit pr
+      command: ~/.config/gh-dash/edit-gh-pr {{.RepoName}} {{.PrNumber}}
+    - key: E
+      name: open repo in emacs
+      command: emacsclient {{.RepoPath}} &
+  issues:
+    - key: v
+      name: view
+      command: gh issue view --repo {{.RepoName}} {{.IssueNumber}} | glow -p
+    - key: l
+      name: add label
+      command: gh issue --repo {{.RepoName}} edit {{.IssueNumber}} --add-label $(gum choose bug enhancement question dependencies wontfix)
+    - key: L
+      name: remove label
+      command: gh issue --repo {{.RepoName}} edit {{.IssueNumber}} --remove-label $(gum choose bug enhancement question dependencies wontfix)
+    - key: E
+      name: open repo in emacs
+      command: emacsclient {{.RepoPath}} &
+
+theme:
+  ui:
+    sectionsShowCount: true
+    table:
+      compact: false
+      showSeparator: true
+  colors:
+    text:
+      primary: "#E2E1ED"
+      secondary: "#6770cb"
+      inverted: "#242347"
+      faint: "#b0793b"
+      warning: "#E0AF68"
+      success: "#3DF294"
+    background:
+      selected: "#1B1B33"
+    border:
+      primary: "#383B5B"
+      secondary: "#39386B"
+      faint: "#8d3e0b"
+
+repoPaths: 
+    :owner/:repo: ~/dev/:repo
+
+pager:
+  diff: delta

.github/ISSUE_TEMPLATE/bug_report.md

@@ -1,31 +0,0 @@
----
-name: Bug report
-about: Create a report to help us improve
-title: "[bug-report]"
-labels: bug
-assignees: TLINDEN
-
----
-
-**Describtion**
-<!-- Please provide a clear and concise description of the issue: -->
-
-
-**Steps To Reproduce**
-<!-- Please detail the steps to reproduce the behavior: -->
-
-
-**Expected behavior**
-<!-- What do you expected to happen instead? -->
-
-
-**Version information**
-<!--
-Please provide as much version information as possible:
-- if you have just installed a binary, provide the output of: rpn -v
-- if you installed from source, provide the output of: make show-version
-- provide additional details: operating system and version and shell environment
--->
-
-
-**Additional informations**

.github/ISSUE_TEMPLATE/feature_request.md

@@ -1,23 +0,0 @@
----
-name: Feature request
-about: Suggest a feature
-title: "[feature-request]"
-labels: feature-request
-assignees: TLINDEN
-
----
-
-**Describtion**
-<!-- Please provide a clear and concise description of the feature you desire: -->
-
-
-
-**Version information**
-<!--
-Just in case the feature is already present, please provide as
-much version information as possible:
-- if you have just installed a binary, provide the output of: rpn -v
-- if you installed from source, provide the output of: make show-version
-- provide additional details: operating system and version and shell environment
--->
-

.github/dependabot.yml

@@ -0,0 +1,10 @@
+version: 2
+updates:
+  - package-ecosystem: "gomod"
+    directory: "/"
+    schedule:
+      interval: "monthly"
+  - package-ecosystem: "github-actions"
+    directory: "/"
+    schedule:
+        interval: "monthly"

.github/workflows/ci.yaml

@@ -1,36 +0,0 @@
-name: build-and-test-rpn
-on: [push, pull_request]
-jobs:
-  build:
-    strategy:
-      matrix:
-        version: [1.21]
-        os: [ubuntu-latest, windows-latest, macos-latest]
-    name: Build
-    runs-on: ${{ matrix.os }}
-    steps:
-    - name: Set up Go
-      uses: actions/setup-go@v3
-      with:
-        go-version: ${{ matrix.version }}
-      id: go
-
-    - name: checkout
-      uses: actions/checkout@v3
-
-    - name: build
-      run: go build
-
-    - name: test
-      run: make test
-
-  golangci:
-    name: lint
-    runs-on: ubuntu-latest
-    steps:
-      - uses: actions/setup-go@v3
-        with:
-          go-version: 1.21
-      - uses: actions/checkout@v3
-      - name: golangci-lint
-        uses: golangci/golangci-lint-action@v3

.goreleaser.yaml

@@ -0,0 +1,69 @@
+# vim: set ts=2 sw=2 tw=0 fo=cnqoj
+
+version: 2
+
+before:
+  hooks:
+    - go mod tidy
+
+gitea_urls:
+  api: https://codeberg.org/api/v1
+  download: https://codeberg.org
+  
+builds:
+  - env:
+      - CGO_ENABLED=0
+    goos:
+      - linux
+      - windows
+      - darwin
+      - freebsd
+
+archives:
+  - formats: [tar.gz]
+    # this name template makes the OS and Arch compatible with the results of `uname`.
+    name_template: >-
+      {{ .ProjectName }}_
+      {{- title .Os }}_
+      {{- if eq .Arch "amd64" }}x86_64
+      {{- else if eq .Arch "386" }}i386
+      {{- else }}{{ .Arch }}{{ end }}
+      {{- if .Arm }}v{{ .Arm }}{{ end }}_{{ .Tag }}
+    # use zip for windows archives
+    format_overrides:
+      - goos: windows
+        formats: [zip]
+      - goos: linux
+        formats: [tar.gz,binary]
+    files:
+      - src: "*.md"
+        strip_parent: true
+      - src: "docs/*"
+        strip_parent: true
+      - src: Makefile.dist
+        dst: Makefile
+    wrap_in_directory: true
+
+changelog:
+  sort: asc
+  filters:
+    exclude:
+      - "^docs:"
+      - "^test:"
+  groups:
+    - title: Improved
+      regexp: '^.*?(feat|add|new)(\([[:word:]]+\))??!?:.+$'
+      order: 0
+    - title: Fixed
+      regexp: '^.*?(bug|fix)(\([[:word:]]+\))??!?:.+$'
+      order: 1
+    - title: Changed
+      order: 999
+
+release:
+  header: "# Release Notes"
+  footer: >-
+
+    ---
+
+    Full Changelog: [{{ .PreviousTag }}...{{ .Tag }}](https://codeberg.org/scip/rpnc/compare/{{ .PreviousTag }}...{{ .Tag }})

.woodpecker/build.yaml

@@ -0,0 +1,27 @@
+matrix:
+  platform:
+    - linux/amd64
+  goversion:
+    - 1.24
+
+labels:
+  platform: ${platform}
+    
+steps:
+  build:
+    when:
+      event: [push]
+    image: golang:${goversion}
+    commands:
+      - go get
+      - go build
+      - go test
+
+  linter:
+    when:
+      event: [push]
+    image: golang:${goversion}
+    commands:
+      - curl -sSfL https://raw.githubusercontent.com/golangci/golangci-lint/HEAD/install.sh | sh -s -- -b $(go env GOPATH)/bin v2.5.0
+      - golangci-lint --version
+      - golangci-lint run ./...

.woodpecker/release.yaml

@@ -0,0 +1,15 @@
+# build release
+
+labels:
+  platform: linux/amd64
+    
+steps:
+  goreleaser:
+    image: goreleaser/goreleaser
+    when:
+      event: [tag]
+    environment:
+      GITEA_TOKEN:
+        from_secret: DEPLOY_TOKEN
+    commands:
+      - goreleaser release --clean --verbose

Makefile

@@ -25,20 +25,20 @@ UID       = root
 GID       = 0
 HAVE_POD := $(shell pod2text -h 2>/dev/null)
 
-all: $(tool).1 $(tool).go buildlocal
+all: $(tool).1 cmd/$(tool).go buildlocal
 
 %.1: %.pod
 ifdef HAVE_POD
 	  pod2man -c "User Commands" -r 1 -s 1 $*.pod > $*.1
 endif
 
-%.go: %.pod
+cmd/%.go: %.pod
 ifdef HAVE_POD
-	  echo "package main" > $*.go
-	  echo >> $*.go
-	  echo "var manpage = \`" >> $*.go
-	  pod2text $*.pod >> $*.go
-	  echo "\`" >> $*.go
+	  echo "package main" > cmd/$*.go
+	  echo >> cmd/$*.go
+	  echo "var manpage = \`" >> cmd/$*.go
+	  pod2text cmd/$*.pod >> cmd/$*.go
+	  echo "\`" >> cmd/$*.go
 endif
 
 buildlocal:
@@ -51,14 +51,25 @@ install: buildlocal
 	install -o $(UID) -g $(GID) -m 444 $(tool).1 $(PREFIX)/man/man1/
 
 clean:
-	rm -rf $(tool) coverage.out
+	rm -rf $(tool) coverage.out testdata
 
-test:
-	go test -v ./...
+test: clean
+	go test ./... $(ARGS)
+
+testfuzzy: clean
+	go test -fuzz ./... $(ARGS)
+
+testlint: test lint
+
+lint:
+	golangci-lint run
+
+lint-full:
+	golangci-lint run --enable-all --exclude-use-default --disable exhaustivestruct,exhaustruct,depguard,interfacer,deadcode,golint,structcheck,scopelint,varcheck,ifshort,maligned,nosnakecase,godot,funlen,gofumpt,cyclop,noctx,gochecknoglobals,paralleltest,forbidigo,godox,dupword,forcetypeassert,goerr113,gomnd
 
 singletest:
-	@echo "Call like this: ''make singletest TEST=TestPrepareColumns"
-	go test -run $(TEST)
+	@echo "Call like this: make singletest TEST=TestPrepareColumns ARGS=-v"
+	go test -run $(TEST) $(ARGS)
 
 cover-report:
 	go test ./... -cover -coverprofile=coverage.out
@@ -70,8 +81,8 @@ goupdate:
 buildall:
 	./mkrel.sh $(tool) $(VERSION)
 
-release: buildall
-	gh release create v$(VERSION) --generate-notes releases/*
+release:
+	gh release create v$(VERSION) --generate-notes
 
 show-versions: buildlocal
 	@echo "### rpn version:"

Makefile.dist

@@ -0,0 +1,20 @@
+# -*-make-*-
+
+.PHONY: install all
+
+tool   = rpn
+PREFIX = /usr/local
+UID    = root
+GID    = 0
+
+all:
+	@echo "Type 'sudo make install' to install the tool."
+	@echo "To change prefix, type 'sudo make install PREFIX=/opt'"
+
+install:
+	install -d -o $(UID) -g $(GID) $(PREFIX)/bin
+	install -d -o $(UID) -g $(GID) $(PREFIX)/man/man1
+	install -d -o $(UID) -g $(GID) $(PREFIX)/share/doc
+	install -o $(UID) -g $(GID) -m 555 $(tool)  $(PREFIX)/sbin/
+	install -o $(UID) -g $(GID) -m 444 $(tool).1 $(PREFIX)/man/man1/
+	install -o $(UID) -g $(GID) -m 444 *.md $(PREFIX)/share/doc/

README.md

@@ -1,8 +1,8 @@
-## Programmable command-line calculator using reverse polish notation
+[![status-badge](https://ci.codeberg.org/api/badges/15511/status.svg)](https://ci.codeberg.org/repos/15511)
+[![License](https://img.shields.io/badge/license-GPL-blue.svg)](https://codeberg.org/scip/rpnc/raw/branch/master/LICENSE)
+[![Go Report Card](https://goreportcard.com/badge/codeberg.org/scip/rpnc)](https://goreportcard.com/report/codeberg.org/scip/rpnc) 
 
-[![Actions](https://github.com/tlinden/rpnc/actions/workflows/ci.yaml/badge.svg)](https://github.com/tlinden/rpnc/actions)
-[![License](https://img.shields.io/badge/license-GPL-blue.svg)](https://github.com/tlinden/rpnc/blob/master/LICENSE)
-[![Go Report Card](https://goreportcard.com/badge/github.com/tlinden/rpnc)](https://goreportcard.com/report/github.com/tlinden/rpnc) 
+## Programmable command-line calculator using reverse polish notation
 
 This is a small commandline calculator which takes its input in
 [reverse polish notation](https://en.wikipedia.org/wiki/Reverse_Polish_notation)
@@ -10,6 +10,7 @@ form.
 
 Features:
 
+
 - unlimited stack
 - undo
 - various stack manipulation commands
@@ -23,6 +24,7 @@ Features:
 - history
 - comments (comment character is `#`)
 - variables
+- help screen uses comfortable internal pager
 
 ## Demo
 
@@ -225,10 +227,15 @@ the `register()` function to register your functions to the
 calculator. This function takes these parameters:
 
 - function name
-- number of arguments expected (1,2 or -1 allowed), -1 means batch
-  mode
+- number of arguments expected (see below)
 - help text
 
+Number of expected arguments can be:
+
+- 0: expect 1 argument but do NOT modify the stack
+- 1-n: do a singular calculation
+- -1: batch mode work with all numbers on the stack 
+
 Please [refer to the lua language
 reference](https://www.lua.org/manual/5.4/) for more details about
 LUA.
@@ -241,7 +248,12 @@ connection to the outside!**
 
 There are multiple ways to install **rpn**:
 
-- Go to the [latest release page](https://github.com/tlinden/rpn/releases/latest),
+- You can use [stew](https://github.com/marwanhawari/stew) to install rpnc:
+  ```default
+  stew install tlinden/rpnc
+  ```
+
+- Go to the [latest release page](https://codeberg.org/scip/rpn/releases/),
   locate the binary for your operating system and platform.
   
   Download it and put it into some directory within your `$PATH` variable.
@@ -254,7 +266,7 @@ There are multiple ways to install **rpn**:
   
 - You can also install from source. Issue the following commands in your shell:
   ```
-  git clone https://github.com/TLINDEN/rpn.git
+  git clone https://codeberg.org/scip/rpn.git
   cd rpn
   make
   sudo make install
@@ -268,7 +280,7 @@ hesitate to ask me about it, I'll add it.
 
 The  documentation  is  provided  as  a unix  man-page.   It  will  be
 automatically installed if  you install from source.  However, you can
-[read the man-page online](https://github.com/TLINDEN/rpnc/blob/master/rpn.pod)
+[read the man-page online](https://codeberg.org/scip/rpnc/raw/branch/master/rpn.pod)
 
 Or if you cloned  the repository you can read it  this way (perl needs
 to be installed though): `perldoc rpn.pod`.
@@ -285,7 +297,7 @@ best way for me to forget to do something.
 
 In order to report a bug,  unexpected behavior, feature requests or to
 submit    a    patch,    please    open   an    issue    on    github:
-https://github.com/TLINDEN/rpnc/issues.
+https://codeberg.org/scip/rpnc/issues.
 
 ## Copyright and license
 
@@ -297,4 +309,4 @@ T.v.Dein <tom AT vondein DOT org>
 
 ## Project homepage
 
-https://github.com/TLINDEN/rpnc
+https://codeberg.org/scip/rpnc

calc_test.go

@@ -1,214 +0,0 @@
-/*
-Copyright © 2023 Thomas von Dein
-
-This program is free software: you can redistribute it and/or modify
-it under the terms of the GNU General Public License as published by
-the Free Software Foundation, either version 3 of the License, or
-(at your option) any later version.
-
-This program is distributed in the hope that it will be useful,
-but WITHOUT ANY WARRANTY; without even the implied warranty of
-MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-GNU General Public License for more details.
-
-You should have received a copy of the GNU General Public License
-along with this program. If not, see <http://www.gnu.org/licenses/>.
-*/
-
-package main
-
-import (
-	"fmt"
-	"testing"
-)
-
-func TestCommentsAndWhitespace(t *testing.T) {
-	calc := NewCalc()
-
-	var tests = []struct {
-		name string
-		cmd  []string
-		exp  float64 // last element of the stack
-	}{
-		{
-			name: "whitespace prefix",
-			cmd:  []string{"  5"},
-			exp:  5.0,
-		},
-		{
-			name: "whitespace postfix",
-			cmd:  []string{"5  "},
-			exp:  5.0,
-		},
-		{
-			name: "whitespace both",
-			cmd:  []string{"  5   "},
-			exp:  5.0,
-		},
-		{
-			name: "comment line w/ spaces",
-			cmd:  []string{"5", "   #   19"},
-			exp:  5.0,
-		},
-		{
-			name: "comment line w/o spaces",
-			cmd:  []string{"5", `#19`},
-			exp:  5.0,
-		},
-		{
-			name: "inline comment w/ spaces",
-			cmd:  []string{"5   #   19"},
-			exp:  5.0,
-		},
-		{
-			name: "inline comment w/o spaces",
-			cmd:  []string{"5#19"},
-			exp:  5.0,
-		},
-	}
-
-	for _, tt := range tests {
-		testname := fmt.Sprintf("%s .(expect %.2f)",
-			tt.name, tt.exp)
-
-		t.Run(testname, func(t *testing.T) {
-			for _, line := range tt.cmd {
-				calc.Eval(line)
-			}
-			got := calc.stack.Last()
-
-			if len(got) > 0 {
-				if got[0] != tt.exp {
-					t.Errorf("parsing failed:\n+++  got: %f\n--- want: %f",
-						got, tt.exp)
-				}
-			}
-
-			if calc.stack.Len() != 1 {
-				t.Errorf("invalid stack size:\n+++  got: %d\n--- want: 1",
-					calc.stack.Len())
-			}
-
-		})
-
-		calc.stack.Clear()
-	}
-}
-
-func TestCalc(t *testing.T) {
-	calc := NewCalc()
-
-	var tests = []struct {
-		name  string
-		cmd   string
-		exp   float64
-		batch bool
-	}{
-		{
-			name: "plus",
-			cmd:  `15 15 +`,
-			exp:  30,
-		},
-		{
-			name: "power",
-			cmd:  `4 2 ^`,
-			exp:  16,
-		},
-		{
-			name: "minus",
-			cmd:  `100 50 -`,
-			exp:  50,
-		},
-		{
-			name: "multi",
-			cmd:  `4 4 x`,
-			exp:  16,
-		},
-		{
-			name: "divide",
-			cmd:  `10 2 /`,
-			exp:  5,
-		},
-		{
-			name: "percent",
-			cmd:  `400 20 %`,
-			exp:  80,
-		},
-		{
-			name: "percent-minus",
-			cmd:  `400 20 %-`,
-			exp:  320,
-		},
-		{
-			name: "percent-plus",
-			cmd:  `400 20 %+`,
-			exp:  480,
-		},
-		{
-			name: "mod",
-			cmd:  `9 2 mod`,
-			exp:  1,
-		},
-		{
-			name: "sqrt",
-			cmd:  `16 sqrt`,
-			exp:  4,
-		},
-		{
-			name: "ceil",
-			cmd:  `15.5 ceil`,
-			exp:  16,
-		},
-		{
-			name: "dim",
-			cmd:  `6 4 dim`,
-			exp:  2,
-		},
-		{
-			name:  "batch-sum",
-			cmd:   `2 2 2 2 sum`,
-			exp:   8,
-			batch: true,
-		},
-		{
-			name:  "batch-median",
-			cmd:   `1 2 3 4 5 median`,
-			exp:   3,
-			batch: true,
-		},
-		{
-			name:  "batch-mean",
-			cmd:   `2 2 8 2 2 mean`,
-			exp:   3.2,
-			batch: true,
-		},
-		{
-			name:  "batch-min",
-			cmd:   `1 2 3 4 5 min`,
-			exp:   1,
-			batch: true,
-		},
-		{
-			name:  "batch-max",
-			cmd:   `1 2 3 4 5 max`,
-			exp:   5,
-			batch: true,
-		},
-	}
-
-	for _, tt := range tests {
-		testname := fmt.Sprintf("cmd-%s-expect-%.2f",
-			tt.name, tt.exp)
-
-		t.Run(testname, func(t *testing.T) {
-			calc.batch = tt.batch
-			calc.Eval(tt.cmd)
-			got := calc.Result()
-			calc.stack.Clear()
-			if got != tt.exp {
-				t.Errorf("calc failed:\n+++  got: %f\n--- want: %f",
-					got, tt.exp)
-			}
-		})
-	}
-}

cmd/calc.go

@@ -1,5 +1,5 @@
 /*
-Copyright © 2023 Thomas von Dein
+Copyright © 2023-2024 Thomas von Dein
 
 This program is free software: you can redistribute it and/or modify
 it under the terms of the GNU General Public License as published by
@@ -15,13 +15,14 @@ You should have received a copy of the GNU General Public License
 along with this program. If not, see <http://www.gnu.org/licenses/>.
 */
 
-package main
+package cmd
 
 import (
 	"errors"
 	"fmt"
-	"os"
+	"math"
 	"regexp"
+	"sort"
 	"strconv"
 	"strings"
 
@@ -35,6 +36,8 @@ type Calc struct {
 	showstack    bool
 	intermediate bool
 	notdone      bool // set to true as long as there are items left in the eval loop
+	precision    int
+
 	stack        *Stack
 	history      []string
 	completer    readline.AutoCompleter
@@ -48,30 +51,25 @@ type Calc struct {
 	Funcalls      Funcalls
 	BatchFuncalls Funcalls
 
+	// different kinds of commands, displays nicer in help output
+	StackCommands    Commands
+	SettingsCommands Commands
+	ShowCommands     Commands
+	Commands         Commands
+
 	Vars map[string]float64
 }
 
 // help for lua functions will be added dynamically
-const Help string = `Available commands:
-batch                toggle batch mode
-debug                toggle debug output
-show                 show the last 5 items of the stack
-dump                 display the stack contents
-clear                clear the whole stack
-shift                remove the last element of the stack
-reverse              reverse the stack elements
-swap                 exchange the last two elements
-vars                 show list of variables
-history              display calculation history
-help|?               show this message
-quit|exit|c-d|c-c    exit program
-
+const Help string = `
 Operators:
 basic operators: + - x * / ^  (* is an alias of x)
 
+Bitwise operators: and or xor < (left shift) > (right shift)
+
 Percent functions:
 %                    percent
-%-                   substract percent
+%-                   subtract percent
 %+                   add percent
 
 Math functions (see https://pkg.go.dev/math):
@@ -80,6 +78,12 @@ erf erfc  erfcinv erfinv exp  exp2 expm1 floor  gamma ilogb j0  j1 log
 log10 log1p log2 logb pow round roundtoeven sin sinh tan tanh trunc y0
 y1 copysign dim hypot
 
+Converter functions:
+cm-to-inch              yards-to-meters         bytes-to-kilobytes
+inch-to-cm              meters-to-yards         bytes-to-megabytes
+gallons-to-liters       miles-to-kilometers     bytes-to-gigabytes
+liters-to-gallons       kilometers-to-miles     bytes-to-terabytes
+
 Batch functions:
 sum                  sum of all values (alias: +)
 max                  max of all values
@@ -94,8 +98,9 @@ Register variables:
 // commands, constants and operators,  defined here to feed completion
 // and our mode switch in Eval() dynamically
 const (
-	Commands  string = `dump reverse debug undebug clear batch shift undo help history manual exit quit swap show vars`
-	Constants string = `Pi Phi Sqrt2 SqrtE SqrtPi SqrtPhi Ln2 Log2E Ln10 Log10E`
+	Constants    string = `Pi Phi Sqrt2 SqrtE SqrtPi SqrtPhi Ln2 Log2E Ln10 Log10E`
+	Precision    int    = 2
+	ShowStackLen int    = 5
 )
 
 // That way we can add custom functions to completion
@@ -107,7 +112,6 @@ func GetCompleteCustomFunctions() func(string) []string {
 			completions = append(completions, luafunc)
 		}
 
-		completions = append(completions, strings.Split(Commands, " ")...)
 		completions = append(completions, strings.Split(Constants, " ")...)
 
 		return completions
@@ -126,41 +130,66 @@ func (c *Calc) GetCompleteCustomFuncalls() func(string) []string {
 			completions = append(completions, function)
 		}
 
+		for command := range c.SettingsCommands {
+			if len(command) > 1 {
+				completions = append(completions, command)
+			}
+		}
+
+		for command := range c.ShowCommands {
+			if len(command) > 1 {
+				completions = append(completions, command)
+			}
+		}
+
+		for command := range c.StackCommands {
+			if len(command) > 1 {
+				completions = append(completions, command)
+			}
+		}
+
+		for command := range c.Commands {
+			if len(command) > 1 {
+				completions = append(completions, command)
+			}
+		}
+
 		return completions
 	}
-
 }
 
 func NewCalc() *Calc {
-	c := Calc{stack: NewStack(), debug: false}
+	calc := Calc{stack: NewStack(), debug: false, precision: Precision}
 
-	c.Funcalls = DefineFunctions()
-	c.BatchFuncalls = DefineBatchFunctions()
-	c.Vars = map[string]float64{}
+	calc.Funcalls = DefineFunctions()
+	calc.BatchFuncalls = DefineBatchFunctions()
+	calc.Vars = map[string]float64{}
 
-	c.completer = readline.NewPrefixCompleter(
+	calc.completer = readline.NewPrefixCompleter(
 		// custom lua functions
 		readline.PcItemDynamic(GetCompleteCustomFunctions()),
-		readline.PcItemDynamic(c.GetCompleteCustomFuncalls()),
+		readline.PcItemDynamic(calc.GetCompleteCustomFuncalls()),
 	)
 
-	c.Space = regexp.MustCompile(`\s+`)
-	c.Comment = regexp.MustCompile(`#.*`) // ignore everything after #
-	c.Register = regexp.MustCompile(`^([<>])([A-Z][A-Z0-9]*)`)
+	calc.Space = regexp.MustCompile(`\s+`)
+	calc.Comment = regexp.MustCompile(`#.*`) // ignore everything after #
+	calc.Register = regexp.MustCompile(`^([<>])([A-Z][A-Z0-9]*)`)
 
 	// pre-calculate mode switching arrays
-	c.Constants = strings.Split(Constants, " ")
+	calc.Constants = strings.Split(Constants, " ")
+
+	calc.SetCommands()
+
+	return &calc
+}
+
+// setup the interpreter, called from main(), import lua functions
+func (c *Calc) SetInt(interpreter *Interpreter) {
+	c.interpreter = interpreter
 
 	for name := range LuaFuncs {
 		c.LuaFunctions = append(c.LuaFunctions, name)
 	}
-
-	return &c
-}
-
-// setup the interpreter, called from main()
-func (c *Calc) SetInt(I *Interpreter) {
-	c.interpreter = I
 }
 
 func (c *Calc) ToggleDebug() {
@@ -183,31 +212,31 @@ func (c *Calc) ToggleShow() {
 }
 
 func (c *Calc) Prompt() string {
-	p := "\033[31m»\033[0m "
-	b := ""
+	prompt := "\033[31m»\033[0m "
+	batch := ""
 
 	if c.batch {
-		b = "->batch"
+		batch = "->batch"
 	}
 
-	d := ""
-	v := ""
+	debug := ""
+	revision := ""
 
 	if c.debug {
-		d = "->debug"
-		v = fmt.Sprintf("/rev%d", c.stack.rev)
+		debug = "->debug"
+		revision = fmt.Sprintf("/rev%d", c.stack.rev)
 	}
 
-	return fmt.Sprintf("rpn%s%s [%d%s]%s", b, d, c.stack.Len(), v, p)
+	return fmt.Sprintf("rpn%s%s [%d%s]%s", batch, debug, c.stack.Len(), revision, prompt)
 }
 
 // the actual work horse, evaluate a line of calc command[s]
-func (c *Calc) Eval(line string) {
+func (c *Calc) Eval(line string) error {
 	// remove surrounding whitespace and comments, if any
 	line = strings.TrimSpace(c.Comment.ReplaceAllString(line, ""))
 
 	if line == "" {
-		return
+		return nil
 	}
 
 	items := c.Space.Split(line, -1)
@@ -219,136 +248,142 @@ func (c *Calc) Eval(line string) {
 			c.notdone = false
 		}
 
-		num, err := strconv.ParseFloat(item, 64)
-
-		if err == nil {
-			c.stack.Backup()
-			c.stack.Push(num)
-		} else {
-			if contains(c.Constants, item) {
-				// put the constant onto the stack
-				c.stack.Backup()
-				c.stack.Push(const2num(item))
-				continue
-			}
-
-			if _, ok := c.Funcalls[item]; ok {
-				if err := c.DoFuncall(item); err != nil {
-					fmt.Println(err)
-				} else {
-					c.Result()
-				}
-				continue
-			}
-
-			if c.batch {
-				if _, ok := c.BatchFuncalls[item]; ok {
-					if err := c.DoFuncall(item); err != nil {
-						fmt.Println(err)
-					} else {
-						c.Result()
-					}
-					continue
-				}
-			} else {
-				if _, ok := c.BatchFuncalls[item]; ok {
-					fmt.Println("only supported in batch mode")
-					continue
-				}
-			}
-
-			if contains(c.LuaFunctions, item) {
-				// user provided custom lua functions
-				c.luafunc(item)
-				continue
-			}
-
-			regmatches := c.Register.FindStringSubmatch(item)
-			if len(regmatches) == 3 {
-				switch regmatches[1] {
-				case ">":
-					c.PutVar(regmatches[2])
-				case "<":
-					c.GetVar(regmatches[2])
-				}
-				continue
-			}
-
-			// management commands
-			switch item {
-			case "?":
-				fallthrough
-			case "help":
-				fmt.Println(Help)
-				if len(LuaFuncs) > 0 {
-					fmt.Println("Lua functions:")
-					for name, function := range LuaFuncs {
-						fmt.Printf("%-20s %s\n", name, function.help)
-					}
-				}
-			case "dump":
-				c.stack.Dump()
-			case "debug":
-				c.ToggleDebug()
-			case "undebug":
-				c.debug = false
-			case "batch":
-				c.ToggleBatch()
-			case "clear":
-				c.stack.Backup()
-				c.stack.Clear()
-			case "shift":
-				c.stack.Backup()
-				c.stack.Shift()
-			case "reverse":
-				c.stack.Backup()
-				c.stack.Reverse()
-			case "swap":
-				if c.stack.Len() < 2 {
-					fmt.Println("stack too small, can't swap")
-				} else {
-					c.stack.Backup()
-					c.stack.Swap()
-				}
-			case "undo":
-				c.stack.Restore()
-			case "history":
-				for _, entry := range c.history {
-					fmt.Println(entry)
-				}
-			case "show":
-				c.ToggleShow()
-			case "exit":
-				fallthrough
-			case "quit":
-				os.Exit(0)
-			case "manual":
-				man()
-			case "vars":
-				if len(c.Vars) > 0 {
-					fmt.Printf("%-20s     %s\n", "VARIABLE", "VALUE")
-					for k, v := range c.Vars {
-						fmt.Printf("%-20s  -> %.2f\n", k, v)
-					}
-				} else {
-					fmt.Println("no vars registered")
-				}
-
-			default:
-				fmt.Println("unknown command or operator!")
-			}
+		if err := c.EvalItem(item); err != nil {
+			return err
 		}
 	}
 
 	if c.showstack && !c.stdin {
 		dots := ""
 
-		if c.stack.Len() > 5 {
+		if c.stack.Len() > ShowStackLen {
 			dots = "... "
 		}
-		last := c.stack.Last(5)
+
+		last := c.stack.Last(ShowStackLen)
+
 		fmt.Printf("stack: %s%s\n", dots, list2str(last))
 	}
+
+	return nil
+}
+
+func (c *Calc) EvalItem(item string) error {
+	num, err := strconv.ParseFloat(item, 64)
+
+	if err == nil {
+		c.stack.Backup()
+		c.stack.Push(num)
+
+		return nil
+	}
+
+	// try time
+	var hour, min int
+	_, err = fmt.Sscanf(item, "%d:%d", &hour, &min)
+	if err == nil {
+		c.stack.Backup()
+		c.stack.Push(float64(hour) + float64(min)/60)
+
+		return nil
+	}
+
+	// try hex
+	var i int
+	_, err = fmt.Sscanf(item, "0x%x", &i)
+	if err == nil {
+		c.stack.Backup()
+		c.stack.Push(float64(i))
+
+		return nil
+	}
+
+	if contains(c.Constants, item) {
+		// put the constant onto the stack
+		c.stack.Backup()
+		c.stack.Push(const2num(item))
+
+		return nil
+	}
+
+	if exists(c.Funcalls, item) {
+		if err := c.DoFuncall(item); err != nil {
+			return Error(err.Error())
+		}
+
+		c.Result()
+
+		return nil
+	}
+
+	if exists(c.BatchFuncalls, item) {
+		if !c.batch {
+			return Error("only supported in batch mode")
+		}
+
+		if err := c.DoFuncall(item); err != nil {
+			return Error(err.Error())
+		}
+
+		c.Result()
+
+		return nil
+	}
+
+	if contains(c.LuaFunctions, item) {
+		// user provided custom lua functions
+		c.EvalLuaFunction(item)
+
+		return nil
+	}
+
+	regmatches := c.Register.FindStringSubmatch(item)
+	if len(regmatches) == 3 {
+		switch regmatches[1] {
+		case ">":
+			c.PutVar(regmatches[2])
+		case "<":
+			c.GetVar(regmatches[2])
+		}
+
+		return nil
+	}
+
+	// internal commands
+	// FIXME: propagate errors
+	if exists(c.Commands, item) {
+		c.Commands[item].Func(c)
+
+		return nil
+	}
+
+	if exists(c.ShowCommands, item) {
+		c.ShowCommands[item].Func(c)
+
+		return nil
+	}
+
+	if exists(c.StackCommands, item) {
+		c.StackCommands[item].Func(c)
+
+		return nil
+	}
+
+	if exists(c.SettingsCommands, item) {
+		c.SettingsCommands[item].Func(c)
+
+		return nil
+	}
+
+	switch item {
+	case "?", "help":
+		c.PrintHelp()
+
+	default:
+		return Error("unknown command or operator")
+	}
+
+	return nil
 }
 
 // Execute a math function, check if it is defined just in case
@@ -361,10 +396,11 @@ func (c *Calc) DoFuncall(funcname string) error {
 	}
 
 	if function == nil {
-		panic("function not defined but in completion list")
+		return Error("function not defined but in completion list")
 	}
 
 	var args Numbers
+
 	batch := false
 
 	if function.Expectargs == -1 {
@@ -386,13 +422,17 @@ func (c *Calc) DoFuncall(funcname string) error {
 	// the  actual lambda call, so  to say. We provide  a slice of
 	// the requested size, fetched  from the stack (but not popped
 	// yet!)
-	R := function.Func(args)
+	funcresult := function.Func(args)
 
-	if R.Err != nil {
+	if funcresult.Err != nil {
 		// leave the stack untouched in case of any error
-		return R.Err
+		return funcresult.Err
 	}
 
+	// don't forget to backup!
+	c.stack.Backup()
+
+	// "pop"
 	if batch {
 		// get rid of stack
 		c.stack.Clear()
@@ -402,10 +442,11 @@ func (c *Calc) DoFuncall(funcname string) error {
 	}
 
 	// save result
-	c.stack.Push(R.Res)
+	c.stack.Push(funcresult.Res)
 
 	// thanks a lot
-	c.SetHistory(funcname, args, R.Res)
+	c.SetHistory(funcname, args, funcresult.Res)
+
 	return nil
 }
 
@@ -430,7 +471,16 @@ func (c *Calc) Result() float64 {
 			fmt.Print("= ")
 		}
 
-		fmt.Println(c.stack.Last()[0])
+		result := c.stack.Last()[0]
+		truncated := math.Trunc(result)
+		precision := c.precision
+
+		if result == truncated {
+			precision = 0
+		}
+
+		format := fmt.Sprintf("%%.%df\n", precision)
+		fmt.Printf(format, result)
 	}
 
 	return c.stack.Last()[0]
@@ -442,43 +492,59 @@ func (c *Calc) Debug(msg string) {
 	}
 }
 
-func (c *Calc) luafunc(funcname string) {
+func (c *Calc) EvalLuaFunction(funcname string) {
 	// called from calc loop
-	var x float64
+	var luaresult float64
+
 	var err error
 
 	switch c.interpreter.FuncNumArgs(funcname) {
+	case 0:
+		fallthrough
 	case 1:
-		x, err = c.interpreter.CallLuaFunc(funcname, c.stack.Last())
+		luaresult, err = c.interpreter.CallLuaFunc(funcname, c.stack.Last())
 	case 2:
-		x, err = c.interpreter.CallLuaFunc(funcname, c.stack.Last(2))
+		luaresult, err = c.interpreter.CallLuaFunc(funcname, c.stack.Last(2))
 	case -1:
-		x, err = c.interpreter.CallLuaFunc(funcname, c.stack.All())
+		luaresult, err = c.interpreter.CallLuaFunc(funcname, c.stack.All())
 	default:
-		x, err = 0, errors.New("invalid number of argument requested")
+		luaresult, err = 0, errors.New("invalid number of argument requested")
 	}
 
 	if err != nil {
 		fmt.Println(err)
+
 		return
 	}
 
 	c.stack.Backup()
 
+	dopush := true
+
 	switch c.interpreter.FuncNumArgs(funcname) {
+	case 0:
+		a := c.stack.Last()
+
+		if len(a) == 1 {
+			c.History("%s(%f) = %f", funcname, a, luaresult)
+		}
+
+		dopush = false
 	case 1:
 		a := c.stack.Pop()
-		c.History("%s(%f) = %f", funcname, a, x)
+		c.History("%s(%f) = %f", funcname, a, luaresult)
 	case 2:
 		a := c.stack.Pop()
 		b := c.stack.Pop()
-		c.History("%s(%f,%f) = %f", funcname, a, b, x)
+		c.History("%s(%f,%f) = %f", funcname, a, b, luaresult)
 	case -1:
 		c.stack.Clear()
-		c.History("%s(*) = %f", funcname, x)
+		c.History("%s(*) = %f", funcname, luaresult)
 	}
 
-	c.stack.Push(x)
+	if dopush {
+		c.stack.Push(luaresult)
+	}
 
 	c.Result()
 }
@@ -495,7 +561,7 @@ func (c *Calc) PutVar(name string) {
 }
 
 func (c *Calc) GetVar(name string) {
-	if _, ok := c.Vars[name]; ok {
+	if exists(c.Vars, name) {
 		c.Debug(fmt.Sprintf("retrieve %.2f from %s", c.Vars[name], name))
 		c.stack.Backup()
 		c.stack.Push(c.Vars[name])
@@ -503,3 +569,56 @@ func (c *Calc) GetVar(name string) {
 		fmt.Println("variable doesn't exist")
 	}
 }
+
+func sortcommands(hash Commands) []string {
+	keys := make([]string, 0, len(hash))
+
+	for key := range hash {
+		if len(key) > 1 {
+			keys = append(keys, key)
+		}
+	}
+
+	sort.Strings(keys)
+
+	return keys
+}
+
+func (c *Calc) PrintHelp() {
+	output := "Available configuration commands:\n"
+
+	for _, name := range sortcommands(c.SettingsCommands) {
+		output += fmt.Sprintf("%-20s %s\n", name, c.SettingsCommands[name].Help)
+	}
+
+	output += "\nAvailable show commands:\n"
+
+	for _, name := range sortcommands(c.ShowCommands) {
+		output += fmt.Sprintf("%-20s %s\n", name, c.ShowCommands[name].Help)
+	}
+
+	output += "\nAvailable stack manipulation commands:\n"
+
+	for _, name := range sortcommands(c.StackCommands) {
+		output += fmt.Sprintf("%-20s %s\n", name, c.StackCommands[name].Help)
+	}
+
+	output += "\nOther commands:\n"
+
+	for _, name := range sortcommands(c.Commands) {
+		output += fmt.Sprintf("%-20s %s\n", name, c.Commands[name].Help)
+	}
+
+	output += "\n" + Help
+
+	// append lua functions, if any
+	if len(LuaFuncs) > 0 {
+		output += "\nLua functions:\n"
+
+		for name, function := range LuaFuncs {
+			output += fmt.Sprintf("%-20s %s\n", name, function.help)
+		}
+	}
+
+	Pager("rpn help overview", output)
+}

cmd/calc_test.go

@@ -0,0 +1,424 @@
+/*
+Copyright © 2023 Thomas von Dein
+
+This program is free software: you can redistribute it and/or modify
+it under the terms of the GNU General Public License as published by
+the Free Software Foundation, either version 3 of the License, or
+(at your option) any later version.
+
+This program is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+GNU General Public License for more details.
+
+You should have received a copy of the GNU General Public License
+along with this program. If not, see <http://www.gnu.org/licenses/>.
+*/
+
+package cmd
+
+import (
+	"fmt"
+	"strconv"
+	"strings"
+	"testing"
+
+	lua "github.com/yuin/gopher-lua"
+)
+
+func TestCommentsAndWhitespace(t *testing.T) {
+	calc := NewCalc()
+
+	var tests = []struct {
+		name string
+		cmd  []string
+		exp  float64 // last element of the stack
+	}{
+		{
+			name: "whitespace prefix",
+			cmd:  []string{"  5"},
+			exp:  5.0,
+		},
+		{
+			name: "whitespace postfix",
+			cmd:  []string{"5  "},
+			exp:  5.0,
+		},
+		{
+			name: "whitespace both",
+			cmd:  []string{"  5   "},
+			exp:  5.0,
+		},
+		{
+			name: "comment line w/ spaces",
+			cmd:  []string{"5", "   #   19"},
+			exp:  5.0,
+		},
+		{
+			name: "comment line w/o spaces",
+			cmd:  []string{"5", `#19`},
+			exp:  5.0,
+		},
+		{
+			name: "inline comment w/ spaces",
+			cmd:  []string{"5   #   19"},
+			exp:  5.0,
+		},
+		{
+			name: "inline comment w/o spaces",
+			cmd:  []string{"5#19"},
+			exp:  5.0,
+		},
+	}
+
+	for _, test := range tests {
+		testname := fmt.Sprintf("%s .(expect %.2f)",
+			test.name, test.exp)
+
+		t.Run(testname, func(t *testing.T) {
+			for _, line := range test.cmd {
+				if err := calc.Eval(line); err != nil {
+					t.Error(err.Error())
+				}
+			}
+			got := calc.stack.Last()
+
+			if len(got) > 0 {
+				if got[0] != test.exp {
+					t.Errorf("parsing failed:\n+++  got: %f\n--- want: %f",
+						got, test.exp)
+				}
+			}
+
+			if calc.stack.Len() != 1 {
+				t.Errorf("invalid stack size:\n+++  got: %d\n--- want: 1",
+					calc.stack.Len())
+			}
+		})
+
+		calc.stack.Clear()
+	}
+}
+
+func TestCalc(t *testing.T) {
+	calc := NewCalc()
+
+	var tests = []struct {
+		name  string
+		cmd   string
+		exp   float64
+		batch bool
+	}{
+		// ops
+		{
+			name: "plus",
+			cmd:  `15 15 +`,
+			exp:  30,
+		},
+		{
+			name: "power",
+			cmd:  `4 2 ^`,
+			exp:  16,
+		},
+		{
+			name: "minus",
+			cmd:  `100 50 -`,
+			exp:  50,
+		},
+		{
+			name: "multi",
+			cmd:  `4 4 x`,
+			exp:  16,
+		},
+		{
+			name: "divide",
+			cmd:  `10 2 /`,
+			exp:  5,
+		},
+		{
+			name: "percent",
+			cmd:  `400 20 %`,
+			exp:  80,
+		},
+		{
+			name: "percent-minus",
+			cmd:  `400 20 %-`,
+			exp:  320,
+		},
+		{
+			name: "percent-plus",
+			cmd:  `400 20 %+`,
+			exp:  480,
+		},
+
+		// math tests
+		{
+			name: "mod",
+			cmd:  `9 2 mod`,
+			exp:  1,
+		},
+		{
+			name: "sqrt",
+			cmd:  `16 sqrt`,
+			exp:  4,
+		},
+		{
+			name: "ceil",
+			cmd:  `15.5 ceil`,
+			exp:  16,
+		},
+		{
+			name: "dim",
+			cmd:  `6 4 dim`,
+			exp:  2,
+		},
+
+		// constants tests
+		{
+			name: "pitimes2",
+			cmd:  `Pi 2 *`,
+			exp:  6.283185307179586,
+		},
+		{
+			name: "pi+sqrt2",
+			cmd:  `Pi Sqrt2 +`,
+			exp:  4.555806215962888,
+		},
+
+		// batch tests
+		{
+			name:  "batch-sum",
+			cmd:   `2 2 2 2 sum`,
+			exp:   8,
+			batch: true,
+		},
+		{
+			name:  "batch-median",
+			cmd:   `1 2 3 4 5 median`,
+			exp:   3,
+			batch: true,
+		},
+		{
+			name:  "batch-mean",
+			cmd:   `2 2 8 2 2 mean`,
+			exp:   3.2,
+			batch: true,
+		},
+		{
+			name:  "batch-min",
+			cmd:   `1 2 3 4 5 min`,
+			exp:   1,
+			batch: true,
+		},
+		{
+			name:  "batch-max",
+			cmd:   `1 2 3 4 5 max`,
+			exp:   5,
+			batch: true,
+		},
+
+		// stack tests
+		{
+			name: "use-vars",
+			cmd:  `10 >TEN clear 5 <TEN *`,
+			exp:  50,
+		},
+		{
+			name: "reverse",
+			cmd:  `100 500 reverse -`,
+			exp:  400,
+		},
+		{
+			name: "swap",
+			cmd:  `2 16 swap /`,
+			exp:  8,
+		},
+		{
+			name:  "clear batch",
+			cmd:   "1 1 1 1 1 clear 1 1 sum",
+			exp:   2,
+			batch: true,
+		},
+		{
+			name: "undo",
+			cmd:  `4 4 + undo *`,
+			exp:  16,
+		},
+
+		// bit tests
+		{
+			name: "bit and",
+			cmd:  `1 3 and`,
+			exp:  1,
+		},
+		{
+			name: "bit or",
+			cmd:  `1 3 or`,
+			exp:  3,
+		},
+		{
+			name: "bit xor",
+			cmd:  `1 3 xor`,
+			exp:  2,
+		},
+
+		// converters
+		{
+			name: "inch-to-cm",
+			cmd:  `111 inch-to-cm`,
+			exp:  281.94,
+		},
+		{
+			name: "gallons-to-liters",
+			cmd:  `111 gallons-to-liters`,
+			exp:  420.135,
+		},
+		{
+			name: "meters-to-yards",
+			cmd:  `111 meters-to-yards`,
+			exp:  1.2139107611548556,
+		},
+		{
+			name: "miles-to-kilometers",
+			cmd:  `111 miles-to-kilometers`,
+			exp:  178.599,
+		},
+	}
+
+	for _, test := range tests {
+		testname := fmt.Sprintf("cmd-%s-expect-%.2f",
+			test.name, test.exp)
+
+		t.Run(testname, func(t *testing.T) {
+			calc.batch = test.batch
+			if err := calc.Eval(test.cmd); err != nil {
+				t.Error(err.Error())
+			}
+			got := calc.Result()
+			calc.stack.Clear()
+			if got != test.exp {
+				t.Errorf("calc failed:\n+++  got: %f\n--- want: %f",
+					got, test.exp)
+			}
+		})
+	}
+}
+
+func TestCalcLua(t *testing.T) {
+	var tests = []struct {
+		function string
+		stack    []float64
+		exp      float64
+	}{
+		{
+			function: "lower",
+			stack:    []float64{5, 6},
+			exp:      5.0,
+		},
+		{
+			function: "parallelresistance",
+			stack:    []float64{100, 200, 300},
+			exp:      54.54545454545455,
+		},
+	}
+
+	calc := NewCalc()
+
+	LuaInterpreter = lua.NewState(lua.Options{SkipOpenLibs: true})
+	defer LuaInterpreter.Close()
+
+	luarunner := NewInterpreter("../example.lua", false)
+	luarunner.InitLua()
+	calc.SetInt(luarunner)
+
+	for _, test := range tests {
+		testname := fmt.Sprintf("lua-%s", test.function)
+
+		t.Run(testname, func(t *testing.T) {
+			calc.stack.Clear()
+			for _, item := range test.stack {
+				calc.stack.Push(item)
+			}
+
+			calc.EvalLuaFunction(test.function)
+
+			got := calc.stack.Last()
+
+			if calc.stack.Len() != 1 {
+				t.Errorf("invalid stack size:\n+++  got: %d\n--- want: 1",
+					calc.stack.Len())
+			}
+
+			if got[0] != test.exp {
+				t.Errorf("lua function %s failed:\n+++  got: %f\n--- want: %f",
+					test.function, got, test.exp)
+			}
+		})
+	}
+}
+
+func FuzzEval(f *testing.F) {
+	legal := []string{
+		"dump",
+		"showstack",
+		"help",
+		"Pi 31 *",
+		"SqrtE Pi /",
+		"55.5 yards-to-meters",
+		"2 4 +",
+		"7 8 batch sum",
+		"7 8 %-",
+		"7 8 clear",
+		"7 8 /",
+		"b",
+		"#444",
+		"<X",
+		"?",
+		"help",
+	}
+
+	for _, item := range legal {
+		f.Add(item)
+	}
+
+	calc := NewCalc()
+
+	var hexnum, hour, min int
+
+	f.Fuzz(func(t *testing.T, line string) {
+		t.Logf("Stack:\n%v\nLine: <%s>\n", calc.stack.All(), line)
+		switch line {
+		case "help", "?":
+			return
+		}
+		if err := calc.EvalItem(line); err == nil {
+			t.Logf("given: <%s>", line)
+			// not corpus and empty?
+			if !contains(legal, line) && len(line) > 0 {
+				item := strings.TrimSpace(calc.Comment.ReplaceAllString(line, ""))
+				_, hexerr := fmt.Sscanf(item, "0x%x", &hexnum)
+				_, timeerr := fmt.Sscanf(item, "%d:%d", &hour, &min)
+				// no comment?
+				if len(item) > 0 {
+					// no known command or function?
+					if _, err := strconv.ParseFloat(item, 64); err != nil {
+						if !contains(calc.Constants, item) &&
+							!exists(calc.Funcalls, item) &&
+							!exists(calc.BatchFuncalls, item) &&
+							!contains(calc.LuaFunctions, item) &&
+							!exists(calc.Commands, item) &&
+							!exists(calc.ShowCommands, item) &&
+							!exists(calc.SettingsCommands, item) &&
+							!exists(calc.StackCommands, item) &&
+							!calc.Register.MatchString(item) &&
+							item != "?" && item != "help" &&
+							hexerr != nil &&
+							timeerr != nil {
+							t.Errorf("Fuzzy input accepted: <%s>", line)
+						}
+					}
+				}
+			}
+		}
+	})
+}

cmd/command.go

@@ -0,0 +1,361 @@
+/*
+Copyright © 2023 Thomas von Dein
+
+This program is free software: you can redistribute it and/or modify
+it under the terms of the GNU General Public License as published by
+the Free Software Foundation, either version 3 of the License, or
+(at your option) any later version.
+
+This program is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+GNU General Public License for more details.
+
+You should have received a copy of the GNU General Public License
+along with this program. If not, see <http://www.gnu.org/licenses/>.
+*/
+
+package cmd
+
+import (
+	"bufio"
+	"fmt"
+	"log"
+	"os"
+	"os/exec"
+	"strconv"
+	"strings"
+)
+
+type CommandFunction func(*Calc)
+
+type Command struct {
+	Help string
+	Func CommandFunction
+}
+
+type Commands map[string]*Command
+
+func NewCommand(help string, function CommandFunction) *Command {
+	return &Command{
+		Help: help,
+		Func: function,
+	}
+}
+
+func (c *Calc) SetSettingsCommands() Commands {
+	return Commands{
+		// Toggles
+		"debug": NewCommand(
+			"toggle debugging",
+			func(c *Calc) {
+				c.ToggleDebug()
+			},
+		),
+
+		"nodebug": NewCommand(
+			"disable debugging",
+			func(c *Calc) {
+				c.debug = false
+				c.stack.debug = false
+			},
+		),
+
+		"batch": NewCommand(
+			"toggle batch mode",
+			func(c *Calc) {
+				c.ToggleBatch()
+			},
+		),
+
+		"nobatch": NewCommand(
+			"disable batch mode",
+			func(c *Calc) {
+				c.batch = false
+			},
+		),
+
+		"showstack": NewCommand(
+			"toggle show last 5 items of the stack",
+			func(c *Calc) {
+				c.ToggleShow()
+			},
+		),
+
+		"noshowstack": NewCommand(
+			"disable display of the stack",
+			func(c *Calc) {
+				c.showstack = false
+			},
+		),
+	}
+}
+
+func (c *Calc) SetShowCommands() Commands {
+	return Commands{
+		// Display commands
+		"dump": NewCommand(
+			"display the stack contents",
+			func(c *Calc) {
+				c.stack.Dump()
+			},
+		),
+
+		"history": NewCommand(
+			"display calculation history",
+			func(c *Calc) {
+				for _, entry := range c.history {
+					fmt.Println(entry)
+				}
+			},
+		),
+
+		"vars": NewCommand(
+			"show list of variables",
+			func(c *Calc) {
+				if len(c.Vars) > 0 {
+					fmt.Printf("%-20s     %s\n", "VARIABLE", "VALUE")
+					for k, v := range c.Vars {
+						fmt.Printf("%-20s  -> %.2f\n", k, v)
+					}
+				} else {
+					fmt.Println("no vars registered")
+				}
+			},
+		),
+
+		"hex": NewCommand(
+			"show last stack item in hex form (converted to int)",
+			func(c *Calc) {
+				if c.stack.Len() > 0 {
+					fmt.Printf("0x%x\n", int(c.stack.Last()[0]))
+				}
+			},
+		),
+	}
+}
+
+func (c *Calc) SetStackCommands() Commands {
+	return Commands{
+		"clear": NewCommand(
+			"clear the whole stack",
+			func(c *Calc) {
+				c.stack.Backup()
+				c.stack.Clear()
+			},
+		),
+
+		"shift": NewCommand(
+			"remove the last element of the stack",
+			func(c *Calc) {
+				c.stack.Backup()
+				c.stack.Shift()
+			},
+		),
+
+		"reverse": NewCommand(
+			"reverse the stack elements",
+			func(c *Calc) {
+				c.stack.Backup()
+				c.stack.Reverse()
+			},
+		),
+
+		"swap": NewCommand(
+			"exchange the last two elements",
+			CommandSwap,
+		),
+
+		"undo": NewCommand(
+			"undo last operation",
+			func(c *Calc) {
+				c.stack.Restore()
+			},
+		),
+
+		"dup": NewCommand(
+			"duplicate last stack item",
+			CommandDup,
+		),
+
+		"edit": NewCommand(
+			"edit the stack interactively",
+			CommandEdit,
+		),
+	}
+}
+
+// define all management (that is: non calculation) commands
+func (c *Calc) SetCommands() {
+	c.SettingsCommands = c.SetSettingsCommands()
+	c.ShowCommands = c.SetShowCommands()
+	c.StackCommands = c.SetStackCommands()
+
+	// general commands
+	c.Commands = Commands{
+		"exit": NewCommand(
+			"exit program",
+			func(c *Calc) {
+				os.Exit(0)
+			},
+		),
+
+		"manual": NewCommand(
+			"show manual",
+			func(c *Calc) {
+				man()
+			},
+		),
+	}
+
+	// aliases
+	c.Commands["quit"] = c.Commands["exit"]
+
+	c.SettingsCommands["d"] = c.SettingsCommands["debug"]
+	c.SettingsCommands["b"] = c.SettingsCommands["batch"]
+	c.SettingsCommands["s"] = c.SettingsCommands["showstack"]
+
+	c.SettingsCommands["togglebatch"] = c.SettingsCommands["batch"]
+	c.SettingsCommands["toggledebug"] = c.SettingsCommands["debug"]
+	c.SettingsCommands["toggleshowstack"] = c.SettingsCommands["showstack"]
+
+	c.ShowCommands["h"] = c.ShowCommands["history"]
+	c.ShowCommands["p"] = c.ShowCommands["dump"]
+	c.ShowCommands["v"] = c.ShowCommands["vars"]
+
+	c.StackCommands["c"] = c.StackCommands["clear"]
+	c.StackCommands["u"] = c.StackCommands["undo"]
+}
+
+// added to the command map:
+func CommandSwap(c *Calc) {
+	if c.stack.Len() < 2 {
+		fmt.Println("stack too small, can't swap")
+	} else {
+		c.stack.Backup()
+		c.stack.Swap()
+	}
+}
+
+func CommandDup(c *Calc) {
+	item := c.stack.Last()
+	if len(item) == 1 {
+		c.stack.Backup()
+		c.stack.Push(item[0])
+	} else {
+		fmt.Println("stack empty")
+	}
+}
+
+func CommandEdit(calc *Calc) {
+	if calc.stack.Len() == 0 {
+		fmt.Println("empty stack")
+
+		return
+	}
+
+	calc.stack.Backup()
+
+	// put the stack contents into a tmp file
+	tmp, err := os.CreateTemp("", "stack")
+	if err != nil {
+		fmt.Println(err)
+
+		return
+	}
+
+	defer func() {
+		if err := os.Remove(tmp.Name()); err != nil {
+			log.Fatal(err)
+		}
+	}()
+
+	comment := `# add or remove numbers as you wish.
+# each number must be on its own line.
+# numbers must be floating point formatted.
+`
+	_, err = tmp.WriteString(comment)
+
+	if err != nil {
+		fmt.Println(err)
+
+		return
+	}
+
+	for _, item := range calc.stack.All() {
+		_, err = fmt.Fprintf(tmp, "%f\n", item)
+		if err != nil {
+			fmt.Println(err)
+
+			return
+		}
+	}
+
+	if err := tmp.Close(); err != nil {
+		log.Fatal(err)
+	}
+
+	// determine which editor to use
+	editor := "vi"
+
+	enveditor, present := os.LookupEnv("EDITOR")
+	if present {
+		if editor != "" {
+			if _, err := os.Stat(editor); err == nil {
+				editor = enveditor
+			}
+		}
+	}
+
+	// execute editor with our tmp file containing current stack
+	cmd := exec.Command(editor, tmp.Name())
+
+	cmd.Stdin = os.Stdin
+	cmd.Stdout = os.Stdout
+	cmd.Stderr = os.Stderr
+
+	err = cmd.Run()
+	if err != nil {
+		fmt.Println("could not run editor command: ", err)
+
+		return
+	}
+
+	// read the file back in
+	modified, err := os.Open(tmp.Name())
+	if err != nil {
+		fmt.Println("Error opening file:", err)
+
+		return
+	}
+	defer func() {
+		if err := modified.Close(); err != nil {
+			log.Fatal(err)
+		}
+	}()
+
+	// reset the stack
+	calc.stack.Clear()
+
+	// and put the new contents (if legit) back onto the stack
+	scanner := bufio.NewScanner(modified)
+	for scanner.Scan() {
+		line := strings.TrimSpace(calc.Comment.ReplaceAllString(scanner.Text(), ""))
+		if line == "" {
+			continue
+		}
+
+		num, err := strconv.ParseFloat(line, 64)
+		if err != nil {
+			fmt.Printf("%s is not a floating point number!\n", line)
+
+			continue
+		}
+
+		calc.stack.Push(num)
+	}
+
+	if err := scanner.Err(); err != nil {
+		fmt.Println("Error reading from file:", err)
+	}
+}

cmd/funcs.go

@@ -0,0 +1,578 @@
+/*
+Copyright © 2023 Thomas von Dein
+
+This program is free software: you can redistribute it and/or modify
+it under the terms of the GNU General Public License as published by
+the Free Software Foundation, either version 3 of the License, or
+(at your option) any later version.
+
+This program is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+GNU General Public License for more details.
+
+You should have received a copy of the GNU General Public License
+along with this program. If not, see <http://www.gnu.org/licenses/>.
+*/
+
+package cmd
+
+import (
+	"errors"
+	"math"
+)
+
+type Result struct {
+	Res float64
+	Err error
+}
+
+type Numbers []float64
+
+type Function func(Numbers) Result
+
+// every function we  are able to call must be  of type Funcall, which
+// needs to  specify how  many numbers  it expects  and the  actual go
+// function to be executed.
+//
+// The function  has to take  a float slice  as argument and  return a
+// float and  an error object. The  float slice is guaranteed  to have
+// the expected number of arguments.
+//
+// However, Lua functions are handled differently, see interpreter.go.
+type Funcall struct {
+	Expectargs int // -1 means batch only mode, you'll get the whole stack as arg
+	Func       Function
+}
+
+// will hold all hard coded functions and operators
+type Funcalls map[string]*Funcall
+
+// convenience function,  create a  new Funcall object,  if expectargs
+// was not specified, 2 is assumed.
+func NewFuncall(function Function, expectargs ...int) *Funcall {
+	expect := 2
+
+	if len(expectargs) > 0 {
+		expect = expectargs[0]
+	}
+
+	return &Funcall{
+		Expectargs: expect,
+		Func:       function,
+	}
+}
+
+// Convenience function, create new result
+func NewResult(n float64, e error) Result {
+	return Result{Res: n, Err: e}
+}
+
+// the actual functions, called once during initialization.
+func DefineFunctions() Funcalls {
+	funcmap := map[string]*Funcall{
+		// simple operators, they all expect 2 args
+		"+": NewFuncall(
+			func(arg Numbers) Result {
+				return NewResult(arg[0]+arg[1], nil)
+			},
+		),
+
+		"-": NewFuncall(
+			func(arg Numbers) Result {
+				return NewResult(arg[0]-arg[1], nil)
+			},
+		),
+
+		"x": NewFuncall(
+			func(arg Numbers) Result {
+				return NewResult(arg[0]*arg[1], nil)
+			},
+		),
+
+		"/": NewFuncall(
+			func(arg Numbers) Result {
+				if arg[1] == 0 {
+					return NewResult(0, errors.New("division by null"))
+				}
+
+				return NewResult(arg[0]/arg[1], nil)
+			},
+		),
+
+		"^": NewFuncall(
+			func(arg Numbers) Result {
+				return NewResult(math.Pow(arg[0], arg[1]), nil)
+			},
+		),
+
+		"%": NewFuncall(
+			func(arg Numbers) Result {
+				return NewResult((arg[0]/100)*arg[1], nil)
+			},
+		),
+
+		"%-": NewFuncall(
+			func(arg Numbers) Result {
+				return NewResult(arg[0]-((arg[0]/100)*arg[1]), nil)
+			},
+		),
+
+		"%+": NewFuncall(
+			func(arg Numbers) Result {
+				return NewResult(arg[0]+((arg[0]/100)*arg[1]), nil)
+			},
+		),
+
+		"mod": NewFuncall(
+			func(arg Numbers) Result {
+				return NewResult(math.Remainder(arg[0], arg[1]), nil)
+			},
+		),
+
+		"sqrt": NewFuncall(
+			func(arg Numbers) Result {
+				return NewResult(math.Sqrt(arg[0]), nil)
+			},
+			1),
+
+		"abs": NewFuncall(
+			func(arg Numbers) Result {
+				return NewResult(math.Abs(arg[0]), nil)
+			},
+			1),
+
+		"acos": NewFuncall(
+			func(arg Numbers) Result {
+				return NewResult(math.Acos(arg[0]), nil)
+			},
+			1),
+
+		"acosh": NewFuncall(
+			func(arg Numbers) Result {
+				return NewResult(math.Acosh(arg[0]), nil)
+			},
+			1),
+
+		"asin": NewFuncall(
+			func(arg Numbers) Result {
+				return NewResult(math.Asin(arg[0]), nil)
+			},
+			1),
+
+		"asinh": NewFuncall(
+			func(arg Numbers) Result {
+				return NewResult(math.Asinh(arg[0]), nil)
+			},
+			1),
+
+		"atan": NewFuncall(
+			func(arg Numbers) Result {
+				return NewResult(math.Atan(arg[0]), nil)
+			},
+			1),
+
+		"atan2": NewFuncall(
+			func(arg Numbers) Result {
+				return NewResult(math.Atan2(arg[0], arg[1]), nil)
+			},
+			2),
+
+		"atanh": NewFuncall(
+			func(arg Numbers) Result {
+				return NewResult(math.Atanh(arg[0]), nil)
+			},
+			1),
+
+		"cbrt": NewFuncall(
+			func(arg Numbers) Result {
+				return NewResult(math.Cbrt(arg[0]), nil)
+			},
+			1),
+
+		"ceil": NewFuncall(
+			func(arg Numbers) Result {
+				return NewResult(math.Ceil(arg[0]), nil)
+			},
+			1),
+
+		"cos": NewFuncall(
+			func(arg Numbers) Result {
+				return NewResult(math.Cos(arg[0]), nil)
+			},
+			1),
+
+		"cosh": NewFuncall(
+			func(arg Numbers) Result {
+				return NewResult(math.Cosh(arg[0]), nil)
+			},
+			1),
+
+		"erf": NewFuncall(
+			func(arg Numbers) Result {
+				return NewResult(math.Erf(arg[0]), nil)
+			},
+			1),
+
+		"erfc": NewFuncall(
+			func(arg Numbers) Result {
+				return NewResult(math.Erfc(arg[0]), nil)
+			},
+			1),
+
+		"erfcinv": NewFuncall(
+			func(arg Numbers) Result {
+				return NewResult(math.Erfcinv(arg[0]), nil)
+			},
+			1),
+
+		"erfinv": NewFuncall(
+			func(arg Numbers) Result {
+				return NewResult(math.Erfinv(arg[0]), nil)
+			},
+			1),
+
+		"exp": NewFuncall(
+			func(arg Numbers) Result {
+				return NewResult(math.Exp(arg[0]), nil)
+			},
+			1),
+
+		"exp2": NewFuncall(
+			func(arg Numbers) Result {
+				return NewResult(math.Exp2(arg[0]), nil)
+			},
+			1),
+
+		"expm1": NewFuncall(
+			func(arg Numbers) Result {
+				return NewResult(math.Expm1(arg[0]), nil)
+			},
+			1),
+
+		"floor": NewFuncall(
+			func(arg Numbers) Result {
+				return NewResult(math.Floor(arg[0]), nil)
+			},
+			1),
+
+		"gamma": NewFuncall(
+			func(arg Numbers) Result {
+				return NewResult(math.Gamma(arg[0]), nil)
+			},
+			1),
+
+		"ilogb": NewFuncall(
+			func(arg Numbers) Result {
+				return NewResult(float64(math.Ilogb(arg[0])), nil)
+			},
+			1),
+
+		"j0": NewFuncall(
+			func(arg Numbers) Result {
+				return NewResult(math.J0(arg[0]), nil)
+			},
+			1),
+
+		"j1": NewFuncall(
+			func(arg Numbers) Result {
+				return NewResult(math.J1(arg[0]), nil)
+			},
+			1),
+
+		"log": NewFuncall(
+			func(arg Numbers) Result {
+				return NewResult(math.Log(arg[0]), nil)
+			},
+			1),
+
+		"log10": NewFuncall(
+			func(arg Numbers) Result {
+				return NewResult(math.Log10(arg[0]), nil)
+			},
+			1),
+
+		"log1p": NewFuncall(
+			func(arg Numbers) Result {
+				return NewResult(math.Log1p(arg[0]), nil)
+			},
+			1),
+
+		"log2": NewFuncall(
+			func(arg Numbers) Result {
+				return NewResult(math.Log2(arg[0]), nil)
+			},
+			1),
+
+		"logb": NewFuncall(
+			func(arg Numbers) Result {
+				return NewResult(math.Logb(arg[0]), nil)
+			},
+			1),
+
+		"pow": NewFuncall(
+			func(arg Numbers) Result {
+				return NewResult(math.Pow(arg[0], arg[1]), nil)
+			},
+			2),
+
+		"round": NewFuncall(
+			func(arg Numbers) Result {
+				return NewResult(math.Round(arg[0]), nil)
+			},
+			1),
+
+		"roundtoeven": NewFuncall(
+			func(arg Numbers) Result {
+				return NewResult(math.RoundToEven(arg[0]), nil)
+			},
+			1),
+
+		"sin": NewFuncall(
+			func(arg Numbers) Result {
+				return NewResult(math.Sin(arg[0]), nil)
+			},
+			1),
+
+		"sinh": NewFuncall(
+			func(arg Numbers) Result {
+				return NewResult(math.Sinh(arg[0]), nil)
+			},
+			1),
+
+		"tan": NewFuncall(
+			func(arg Numbers) Result {
+				return NewResult(math.Tan(arg[0]), nil)
+			},
+			1),
+
+		"tanh": NewFuncall(
+			func(arg Numbers) Result {
+				return NewResult(math.Tanh(arg[0]), nil)
+			},
+			1),
+
+		"trunc": NewFuncall(
+			func(arg Numbers) Result {
+				return NewResult(math.Trunc(arg[0]), nil)
+			},
+			1),
+
+		"y0": NewFuncall(
+			func(arg Numbers) Result {
+				return NewResult(math.Y0(arg[0]), nil)
+			},
+			1),
+
+		"y1": NewFuncall(
+			func(arg Numbers) Result {
+				return NewResult(math.Y1(arg[0]), nil)
+			},
+			1),
+
+		"copysign": NewFuncall(
+			func(arg Numbers) Result {
+				return NewResult(math.Copysign(arg[0], arg[1]), nil)
+			},
+			2),
+
+		"dim": NewFuncall(
+			func(arg Numbers) Result {
+				return NewResult(math.Dim(arg[0], arg[1]), nil)
+			},
+			2),
+
+		"hypot": NewFuncall(
+			func(arg Numbers) Result {
+				return NewResult(math.Hypot(arg[0], arg[1]), nil)
+			},
+			2),
+
+		// converters of all kinds
+		"cm-to-inch": NewFuncall(
+			func(arg Numbers) Result {
+				return NewResult(arg[0]/2.54, nil)
+			},
+			1),
+
+		"inch-to-cm": NewFuncall(
+			func(arg Numbers) Result {
+				return NewResult(arg[0]*2.54, nil)
+			},
+			1),
+
+		"gallons-to-liters": NewFuncall(
+			func(arg Numbers) Result {
+				return NewResult(arg[0]*3.785, nil)
+			},
+			1),
+
+		"liters-to-gallons": NewFuncall(
+			func(arg Numbers) Result {
+				return NewResult(arg[0]/3.785, nil)
+			},
+			1),
+
+		"yards-to-meters": NewFuncall(
+			func(arg Numbers) Result {
+				return NewResult(arg[0]*91.44, nil)
+			},
+			1),
+
+		"meters-to-yards": NewFuncall(
+			func(arg Numbers) Result {
+				return NewResult(arg[0]/91.44, nil)
+			},
+			1),
+
+		"miles-to-kilometers": NewFuncall(
+			func(arg Numbers) Result {
+				return NewResult(arg[0]*1.609, nil)
+			},
+			1),
+
+		"kilometers-to-miles": NewFuncall(
+			func(arg Numbers) Result {
+				return NewResult(arg[0]/1.609, nil)
+			},
+			1),
+
+		"bytes-to-kilobytes": NewFuncall(
+			func(arg Numbers) Result {
+				return NewResult(arg[0]/1024, nil)
+			},
+			1),
+
+		"bytes-to-megabytes": NewFuncall(
+			func(arg Numbers) Result {
+				return NewResult(arg[0]/1024/1024, nil)
+			},
+			1),
+
+		"bytes-to-gigabytes": NewFuncall(
+			func(arg Numbers) Result {
+				return NewResult(arg[0]/1024/1024/1024, nil)
+			},
+			1),
+
+		"bytes-to-terabytes": NewFuncall(
+			func(arg Numbers) Result {
+				return NewResult(arg[0]/1024/1024/1024/1024, nil)
+			},
+			1),
+
+		"or": NewFuncall(
+			func(arg Numbers) Result {
+				return NewResult(float64(int(arg[0])|int(arg[1])), nil)
+			},
+			2),
+
+		"and": NewFuncall(
+			func(arg Numbers) Result {
+				return NewResult(float64(int(arg[0])&int(arg[1])), nil)
+			},
+			2),
+
+		"xor": NewFuncall(
+			func(arg Numbers) Result {
+				return NewResult(float64(int(arg[0])^int(arg[1])), nil)
+			},
+			2),
+
+		"<": NewFuncall(
+			func(arg Numbers) Result {
+				// Shift by negative number provibited, so check it.
+				// Note that we check against uint64 overflow as well here
+				if arg[1] < 0 || uint64(arg[1]) > math.MaxInt64 {
+					return NewResult(0, errors.New("negative shift amount"))
+				}
+
+				return NewResult(float64(int(arg[0])<<int(arg[1])), nil)
+			},
+			2),
+
+		">": NewFuncall(
+			func(arg Numbers) Result {
+				if arg[1] < 0 || uint64(arg[1]) > math.MaxInt64 {
+					return NewResult(0, errors.New("negative shift amount"))
+				}
+
+				return NewResult(float64(int(arg[0])>>int(arg[1])), nil)
+			},
+			2),
+	}
+
+	// aliases
+	funcmap["*"] = funcmap["x"]
+	funcmap["remainder"] = funcmap["mod"]
+
+	return funcmap
+}
+
+func DefineBatchFunctions() Funcalls {
+	funcmap := map[string]*Funcall{
+		"median": NewFuncall(
+			func(args Numbers) Result {
+				middle := len(args) / 2
+
+				return NewResult(args[middle], nil)
+			},
+			-1),
+
+		"mean": NewFuncall(
+			func(args Numbers) Result {
+				var sum float64
+				for _, item := range args {
+					sum += item
+				}
+
+				return NewResult(sum/float64(len(args)), nil)
+			},
+			-1),
+
+		"min": NewFuncall(
+			func(args Numbers) Result {
+				var min float64
+				min, args = args[0], args[1:]
+				for _, item := range args {
+					if item < min {
+						min = item
+					}
+				}
+
+				return NewResult(min, nil)
+			},
+			-1),
+
+		"max": NewFuncall(
+			func(args Numbers) Result {
+				var max float64
+				max, args = args[0], args[1:]
+				for _, item := range args {
+					if item > max {
+						max = item
+					}
+				}
+
+				return NewResult(max, nil)
+			},
+			-1),
+
+		"sum": NewFuncall(
+			func(args Numbers) Result {
+				var sum float64
+				for _, item := range args {
+					sum += item
+				}
+
+				return NewResult(sum, nil)
+			},
+			-1),
+	}
+
+	// aliases
+	funcmap["+"] = funcmap["sum"]
+	funcmap["avg"] = funcmap["mean"]
+
+	return funcmap
+}

cmd/interpreter.go

@@ -15,7 +15,7 @@ You should have received a copy of the GNU General Public License
 along with this program. If not, see <http://www.gnu.org/licenses/>.
 */
 
-package main
+package cmd
 
 import (
 	"errors"
@@ -25,11 +25,12 @@ import (
 )
 
 type Interpreter struct {
-	debug bool
+	debug  bool
+	script string
 }
 
-// LUA interpreter, instanciated in main()
-var L *lua.LState
+// LuaInterpreter is the lua interpreter, instantiated in main()
+var LuaInterpreter *lua.LState
 
 // holds a user provided lua function
 type LuaFunction struct {
@@ -38,12 +39,16 @@ type LuaFunction struct {
 	numargs int
 }
 
-// must be global since init() is  being called from lua which doesn't
-// have access to the interpreter instance
+// LuaFuncs must be global since init() is being called from lua which
+// doesn't have access to the interpreter instance
 var LuaFuncs map[string]LuaFunction
 
+func NewInterpreter(script string, debug bool) *Interpreter {
+	return &Interpreter{debug: debug, script: script}
+}
+
 // initialize the lua environment properly
-func InitLua(config string, debug bool) *Interpreter {
+func (i *Interpreter) InitLua() {
 	// we only  load a subset of lua Open  modules and don't allow
 	// net, system or io stuff
 	for _, pair := range []struct {
@@ -56,8 +61,8 @@ func InitLua(config string, debug bool) *Interpreter {
 		{lua.DebugLibName, lua.OpenDebug},
 		{lua.MathLibName, lua.OpenMath},
 	} {
-		if err := L.CallByParam(lua.P{
-			Fn:      L.NewFunction(pair.f),
+		if err := LuaInterpreter.CallByParam(lua.P{
+			Fn:      LuaInterpreter.NewFunction(pair.f),
 			NRet:    0,
 			Protect: true,
 		}, lua.LString(pair.n)); err != nil {
@@ -66,26 +71,24 @@ func InitLua(config string, debug bool) *Interpreter {
 	}
 
 	// load the lua config (which we expect to contain init() and math functions)
-	if err := L.DoFile(config); err != nil {
+	if err := LuaInterpreter.DoFile(i.script); err != nil {
 		panic(err)
 	}
 
-	// instanciate
+	// instantiate
 	LuaFuncs = map[string]LuaFunction{}
 
 	// that way the user can call register(...) from lua inside init()
-	L.SetGlobal("register", L.NewFunction(register))
+	LuaInterpreter.SetGlobal("register", LuaInterpreter.NewFunction(register))
 
 	// actually call init()
-	if err := L.CallByParam(lua.P{
-		Fn:      L.GetGlobal("init"),
+	if err := LuaInterpreter.CallByParam(lua.P{
+		Fn:      LuaInterpreter.GetGlobal("init"),
 		NRet:    0,
 		Protect: true,
 	}); err != nil {
 		panic(err)
 	}
-
-	return &Interpreter{debug: debug}
 }
 
 func (i *Interpreter) Debug(msg string) {
@@ -105,54 +108,54 @@ func (i *Interpreter) FuncNumArgs(name string) int {
 // arguments. 1 uses the last item of the stack, 2 the last two and -1
 // all items (which translates to batch mode)
 //
-// The  items  array  will  be   provded  by  calc.Eval(),  these  are
+// The  items  array  will  be  provided  by  calc.Eval(),  these  are
 // non-popped stack  items. So  the items will  only removed  from the
-// stack when the lua function execution is successfull.
+// stack when the lua function execution is successful.
 func (i *Interpreter) CallLuaFunc(funcname string, items []float64) (float64, error) {
 	i.Debug(fmt.Sprintf("calling lua func %s() with %d args",
 		funcname, LuaFuncs[funcname].numargs))
 
 	switch LuaFuncs[funcname].numargs {
-	case 1:
+	case 0, 1:
 		// 1 arg variant
-		if err := L.CallByParam(lua.P{
-			Fn:      L.GetGlobal(funcname),
+		if err := LuaInterpreter.CallByParam(lua.P{
+			Fn:      LuaInterpreter.GetGlobal(funcname),
 			NRet:    1,
 			Protect: true,
 		}, lua.LNumber(items[0])); err != nil {
-			fmt.Println(err)
-			return 0, err
+			return 0, fmt.Errorf("failed to exec lua func %s: %w", funcname, err)
 		}
 	case 2:
 		// 2 arg variant
-		if err := L.CallByParam(lua.P{
-			Fn:      L.GetGlobal(funcname),
+		if err := LuaInterpreter.CallByParam(lua.P{
+			Fn:      LuaInterpreter.GetGlobal(funcname),
 			NRet:    1,
 			Protect: true,
 		}, lua.LNumber(items[0]), lua.LNumber(items[1])); err != nil {
-			return 0, err
+			return 0, fmt.Errorf("failed to exec lua func %s: %w", funcname, err)
 		}
 	case -1:
 		// batch variant, use lua table as array
-		tb := L.NewTable()
+		table := LuaInterpreter.NewTable()
 
 		// put the whole stack into it
 		for _, item := range items {
-			tb.Append(lua.LNumber(item))
+			table.Append(lua.LNumber(item))
 		}
 
-		if err := L.CallByParam(lua.P{
-			Fn:      L.GetGlobal(funcname),
+		if err := LuaInterpreter.CallByParam(lua.P{
+			Fn:      LuaInterpreter.GetGlobal(funcname),
 			NRet:    1,
 			Protect: true,
-		}, tb); err != nil {
-			return 0, err
+		}, table); err != nil {
+			return 0, fmt.Errorf("failed to exec lua func %s: %w", funcname, err)
 		}
 	}
 
 	// get result and cast to float64
-	if res, ok := L.Get(-1).(lua.LNumber); ok {
-		L.Pop(1)
+	if res, ok := LuaInterpreter.Get(-1).(lua.LNumber); ok {
+		LuaInterpreter.Pop(1)
+
 		return float64(res), nil
 	}
 
@@ -162,10 +165,10 @@ func (i *Interpreter) CallLuaFunc(funcname string, items []float64) (float64, er
 // called from lua to register a math  function numargs may be 1, 2 or
 // -1, it denotes the number of  items from the stack requested by the
 // lua function. -1 means batch mode, that is all items
-func register(L *lua.LState) int {
-	function := L.ToString(1)
-	numargs := L.ToInt(2)
-	help := L.ToString(3)
+func register(lstate *lua.LState) int {
+	function := lstate.ToString(1)
+	numargs := lstate.ToInt(2)
+	help := lstate.ToString(3)
 
 	LuaFuncs[function] = LuaFunction{
 		name:    function,

cmd/pager.go

@@ -0,0 +1,120 @@
+package cmd
+
+// pager setup using bubbletea
+// file shamlelessly copied from:
+// https://github.com/charmbracelet/bubbletea/tree/main/examples/pager
+
+import (
+	"fmt"
+	"os"
+	"strings"
+
+	"github.com/charmbracelet/bubbles/viewport"
+	tea "github.com/charmbracelet/bubbletea"
+	"github.com/charmbracelet/lipgloss"
+)
+
+var (
+	titleStyle = func() lipgloss.Style {
+		b := lipgloss.RoundedBorder()
+		b.Right = "├"
+		return lipgloss.NewStyle().BorderStyle(b).Padding(0, 1)
+	}()
+
+	infoStyle = func() lipgloss.Style {
+		b := lipgloss.RoundedBorder()
+		b.Left = "┤"
+		return titleStyle.BorderStyle(b)
+	}()
+)
+
+type model struct {
+	content  string
+	title    string
+	ready    bool
+	viewport viewport.Model
+}
+
+func (m model) Init() tea.Cmd {
+	return nil
+}
+
+func (m model) Update(msg tea.Msg) (tea.Model, tea.Cmd) {
+	var (
+		cmd  tea.Cmd
+		cmds []tea.Cmd
+	)
+
+	switch msg := msg.(type) {
+	case tea.KeyMsg:
+		if k := msg.String(); k == "ctrl+c" || k == "q" || k == "esc" {
+			return m, tea.Quit
+		}
+
+	case tea.WindowSizeMsg:
+		headerHeight := lipgloss.Height(m.headerView())
+		footerHeight := lipgloss.Height(m.footerView())
+		verticalMarginHeight := headerHeight + footerHeight
+
+		if !m.ready {
+			// Since this program is using the full size of the viewport we
+			// need to wait until we've received the window dimensions before
+			// we can initialize the viewport. The initial dimensions come in
+			// quickly, though asynchronously, which is why we wait for them
+			// here.
+			m.viewport = viewport.New(msg.Width, msg.Height-verticalMarginHeight)
+			m.viewport.YPosition = headerHeight
+			m.viewport.SetContent(m.content)
+			m.ready = true
+		} else {
+			m.viewport.Width = msg.Width
+			m.viewport.Height = msg.Height - verticalMarginHeight
+		}
+	}
+
+	// Handle keyboard and mouse events in the viewport
+	m.viewport, cmd = m.viewport.Update(msg)
+	cmds = append(cmds, cmd)
+
+	return m, tea.Batch(cmds...)
+}
+
+func (m model) View() string {
+	if !m.ready {
+		return "\n  Initializing..."
+	}
+	return fmt.Sprintf("%s\n%s\n%s", m.headerView(), m.viewport.View(), m.footerView())
+}
+
+func (m model) headerView() string {
+	// title := titleStyle.Render("RPN Help Overview")
+	title := titleStyle.Render(m.title)
+	line := strings.Repeat("─", max(0, m.viewport.Width-lipgloss.Width(title)))
+	return lipgloss.JoinHorizontal(lipgloss.Center, title, line)
+}
+
+func (m model) footerView() string {
+	info := infoStyle.Render(fmt.Sprintf("%3.f%%", m.viewport.ScrollPercent()*100))
+	line := strings.Repeat("─", max(0, m.viewport.Width-lipgloss.Width(info)))
+	return lipgloss.JoinHorizontal(lipgloss.Center, line, info)
+}
+
+func max(a, b int) int {
+	if a > b {
+		return a
+	}
+	return b
+}
+
+func Pager(title, message string) {
+	p := tea.NewProgram(
+		model{content: message, title: title},
+		tea.WithAltScreen(),       // use the full size of the terminal in its "alternate screen buffer"
+		tea.WithMouseCellMotion(), // turn on mouse support so we can track the mouse wheel
+	)
+
+	if _, err := p.Run(); err != nil {
+		fmt.Println("could not run pager:", err)
+		os.Exit(1)
+	}
+}

cmd/root.go

@@ -0,0 +1,195 @@
+/*
+Copyright © 2023-2024 Thomas von Dein
+
+This program is free software: you can redistribute it and/or modify
+it under the terms of the GNU General Public License as published by
+the Free Software Foundation, either version 3 of the License, or
+(at your option) any later version.
+
+This program is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+GNU General Public License for more details.
+
+You should have received a copy of the GNU General Public License
+along with this program. If not, see <http://www.gnu.org/licenses/>.
+*/
+
+package cmd
+
+import (
+	"fmt"
+	"log"
+	"os"
+	"strings"
+
+	"github.com/chzyer/readline"
+	flag "github.com/spf13/pflag"
+	lua "github.com/yuin/gopher-lua"
+)
+
+const VERSION string = "2.1.7"
+
+const Usage string = `This is rpn, a reverse polish notation calculator cli.
+
+Usage: rpn [-bdvh] [<operator>]
+
+Options:
+  -b, --batchmode       enable batch mode
+  -d, --debug           enable debug mode
+  -s, --stack           show last 5 items of the stack (off by default)
+  -i  --intermediate    print intermediate results
+  -m, --manual          show manual
+  -c, --config <file>   load <file> containing LUA code
+  -p, --precision <int> floating point number precision (default 2)
+  -v, --version         show version
+  -h, --help            show help
+
+When <operator>  is given, batch  mode ist automatically  enabled. Use
+this only when working with stdin. E.g.: echo "2 3 4 5" | rpn +
+
+Copyright (c) 2023-2025 T.v.Dein`
+
+func Main() int {
+	calc := NewCalc()
+
+	showversion := false
+	showhelp := false
+	showmanual := false
+	enabledebug := false
+	configfile := ""
+
+	flag.BoolVarP(&calc.batch, "batchmode", "b", false, "batch mode")
+	flag.BoolVarP(&calc.showstack, "show-stack", "s", false, "show stack")
+	flag.BoolVarP(&calc.intermediate, "showin-termediate", "i", false,
+		"show intermediate results")
+	flag.BoolVarP(&enabledebug, "debug", "d", false, "debug mode")
+	flag.BoolVarP(&showversion, "version", "v", false, "show version")
+	flag.BoolVarP(&showhelp, "help", "h", false, "show usage")
+	flag.BoolVarP(&showmanual, "manual", "m", false, "show manual")
+	flag.StringVarP(&configfile, "config", "c",
+		os.Getenv("HOME")+"/.rpn.lua", "config file (lua format)")
+	flag.IntVarP(&calc.precision, "precision", "p", Precision, "floating point precision")
+
+	flag.Parse()
+
+	if showversion {
+		fmt.Printf("This is rpn version %s\n", VERSION)
+
+		return 0
+	}
+
+	if showhelp {
+		fmt.Println(Usage)
+
+		return 0
+	}
+
+	if enabledebug {
+		calc.ToggleDebug()
+	}
+
+	if showmanual {
+		man()
+
+		return 0
+	}
+
+	// the lua state object is global, instantiate it early
+	LuaInterpreter = lua.NewState(lua.Options{SkipOpenLibs: true})
+	defer LuaInterpreter.Close()
+
+	// our config file is interpreted  as lua code, only functions can
+	// be defined, init() will be called by InitLua().
+	if _, err := os.Stat(configfile); err == nil {
+		luarunner := NewInterpreter(configfile, enabledebug)
+		luarunner.InitLua()
+		calc.SetInt(luarunner)
+
+		if calc.debug {
+			fmt.Println("loaded config")
+		}
+	} else if calc.debug {
+		fmt.Println(err)
+	}
+
+	if len(flag.Args()) > 1 {
+		// commandline calc operation, no readline etc needed
+		// called like rpn 2 2 +
+		calc.stdin = true
+		if err := calc.Eval(strings.Join(flag.Args(), " ")); err != nil {
+			fmt.Println(err)
+
+			return 1
+		}
+
+		return 0
+	}
+
+	// interactive mode, need readline
+	reader, err := readline.NewEx(&readline.Config{
+		Prompt:            calc.Prompt(),
+		HistoryFile:       os.Getenv("HOME") + "/.rpn-history",
+		HistoryLimit:      500,
+		AutoComplete:      calc.completer,
+		InterruptPrompt:   "^C",
+		EOFPrompt:         "exit",
+		HistorySearchFold: true,
+	})
+
+	if err != nil {
+		panic(err)
+	}
+	defer func() {
+		if err := reader.Close(); err != nil {
+			log.Fatal(err)
+		}
+	}()
+
+	reader.CaptureExitSignal()
+
+	if inputIsStdin() {
+		// commands are  coming on stdin, however we  will still enter
+		// the same loop since readline just reads fine from stdin
+		calc.ToggleStdin()
+	}
+
+	for {
+		// primary program repl
+		line, err := reader.Readline()
+		if err != nil {
+			break
+		}
+
+		err = calc.Eval(line)
+		if err != nil {
+			fmt.Println(err)
+		}
+
+		reader.SetPrompt(calc.Prompt())
+	}
+
+	if len(flag.Args()) > 0 {
+		// called like this:
+		// echo 1 2 3 4 | rpn +
+		// batch mode enabled automatically
+		calc.batch = true
+		if err = calc.Eval(flag.Args()[0]); err != nil {
+			fmt.Println(err)
+
+			return 1
+		}
+	}
+
+	return 0
+}
+
+func inputIsStdin() bool {
+	stat, _ := os.Stdin.Stat()
+
+	return (stat.Mode() & os.ModeCharDevice) == 0
+}
+
+func man() {
+	Pager("rpn manual page", manpage)
+}

cmd/rpn.go

@@ -1,4 +1,4 @@
-package main
+package cmd
 
 var manpage = `
 NAME
@@ -8,13 +8,15 @@ SYNOPSIS
         Usage: rpn [-bdvh] [<operator>]
     
         Options:
-          -b, --batchmode     enable batch mode
-          -d, --debug         enable debug mode
-          -s, --stack         show last 5 items of the stack (off by default)
-          -i  --intermediate  print intermediate results
-          -m, --manual        show manual
-          -v, --version       show version
-          -h, --help          show help
+          -b, --batchmode       enable batch mode
+          -d, --debug           enable debug mode
+          -s, --stack           show last 5 items of the stack (off by default)
+          -i  --intermediate    print intermediate results
+          -m, --manual          show manual
+          -c, --config <file>   load <file> containing LUA code
+          -p, --precision <int> floating point number precision (default 2)
+          -v, --version         show version
+          -h, --help            show help
     
         When <operator>  is given, batch  mode ist automatically  enabled. Use
         this only when working with stdin. E.g.: echo "2 3 4 5" | rpn +
@@ -105,6 +107,10 @@ DESCRIPTION
     If the first parameter to rpn is a math operator or function, batch mode
     is enabled automatically, see last example.
 
+    You can enter integers, floating point numbers (positive or negative) or
+    hex numbers (prefixed with 0x). Time values in hh::mm format are
+    possible as well.
+
   STACK MANIPULATION
     There are lots of stack manipulation commands provided. The most
     important one is undo which goes back to the stack before the last math
@@ -124,15 +130,23 @@ DESCRIPTION
     Basic operators:
 
         +                    add
-        -                    substract
+        -                    subtract
         /                    divide
         x                    multiply (alias: *)
         ^                    power
 
+    Bitwise operators:
+
+        and                  bitwise and
+        or                   bitwise or
+        xor                  bitwise xor
+        <                    left shift
+        >                    right shift
+
     Percent functions:
 
         %                    percent
-        %-                   substract percent
+        %-                   subtract percent
         %+                   add percent
 
     Batch functions:
@@ -150,18 +164,40 @@ DESCRIPTION
         log10 log1p log2 logb pow round roundtoeven sin sinh tan tanh trunc y0
         y1 copysign dim hypot
 
-    Commands:
+    Conversion functions:
+
+        cm-to-inch          yards-to-meters         bytes-to-kilobytes
+        inch-to-cm          meters-to-yards         bytes-to-megabytes
+        gallons-to-liters   miles-to-kilometers     bytes-to-gigabytes
+        liters-to-gallons   kilometers-to-miles     bytes-to-terabytes
+
+    Configuration Commands:
+
+        [no]batch            toggle batch mode (nobatch turns it off)
+        [no]debug            toggle debug output (nodebug turns it off)
+        [no]showstack        show the last 5 items of the stack (noshowtack turns it off)
+
+    Show commands:
 
-        batch                toggle batch mode
-        debug                toggle debug output
         dump                 display the stack contents
+        hex                  show last stack item in hex form (converted to int)
+        history              display calculation history
+        vars                 show list of variables
+
+    Stack manipulation commands:
+
         clear                clear the whole stack
         shift                remove the last element of the stack
         reverse              reverse the stack elements
         swap                 exchange the last two stack elements
-        show                 show the last 5 items of the stack
-        history              display calculation history
+        dup                  duplicate last stack item
+        undo                 undo last operation
+        edit                 edit the stack interactively using vi or $EDITOR
+
+    Other commands:
+
         help|?               show this message
+        manual               show manual
         quit|exit|c-d|c-c    exit program
 
     Register variables:
@@ -171,6 +207,17 @@ DESCRIPTION
 
     Refer to https://pkg.go.dev/math for details about those functions.
 
+    There are also a number of shortcuts for some commands available:
+
+        d    debug
+        b    batch
+        s    showstack
+        h    history
+        p    dump (aka print)
+        v    vars
+        c    clear
+        u    undo
+
 INTERACTIVE REPL
     While you can use rpn in the command-line, the best experience you'll
     have is the interactive repl (read eval print loop). Just execute "rpn"
@@ -210,7 +257,6 @@ COMMENTS
 
     In this case only 123 will be added to the stack.
 
-
 VARIABLES
     You can register the last item of the stack into a variable. Variable
     names must be all caps. Use the ">NAME" command to put a value into
@@ -245,8 +291,13 @@ EXTENDING RPN USING LUA
 
     *   function name
 
-    *   number of arguments expected (1,2 or -1 allowed), -1 means batch
-        mode.
+    *   number of arguments expected (see below)
+
+        Number of expected arguments can be:
+
+            - 0: expect 1 argument but do NOT modify the stack
+            - 1-n: do a singular calculation
+            - -1: batch mode work with all numbers on the stack
 
     *   help text
 
@@ -257,6 +308,15 @@ EXTENDING RPN USING LUA
     So you can't open files, execute other programs or open a connection to
     the outside!
 
+CONFIGURATION
+    rpn can be configured via command line flags (see usage above). Most of
+    the flags are also available as interactive commands, such as "--batch"
+    has the same effect as the batch command.
+
+    The floating point number precision option "-p, --precision" however is
+    not available as interactive command, it MUST be configured on the
+    command line, if needed. The default precision is 2.
+
 GETTING HELP
     In interactive mode you can enter the help command (or ?) to get a short
     help along with a list of all supported operators and functions.
@@ -270,13 +330,13 @@ GETTING HELP
 BUGS
     In order to report a bug, unexpected behavior, feature requests or to
     submit a patch, please open an issue on github:
-    <https://github.com/TLINDEN/rpnc/issues>.
+    <https://codeberg.org/scip/rpnc/issues>.
 
 LICENSE
     This software is licensed under the GNU GENERAL PUBLIC LICENSE version
     3.
 
-    Copyright (c) 2023 by Thomas von Dein
+    Copyright (c) 2023-2024 by Thomas von Dein
 
     This software uses the following GO modules:
 

cmd/stack.go

@@ -15,7 +15,7 @@ You should have received a copy of the GNU General Public License
 along with this program. If not, see <http://www.gnu.org/licenses/>.
 */
 
-package main
+package cmd
 
 import (
 	"container/list"
@@ -64,14 +64,14 @@ func (s *Stack) Bump() {
 }
 
 // append an item to the stack
-func (s *Stack) Push(x float64) {
+func (s *Stack) Push(item float64) {
 	s.mutex.Lock()
 	defer s.mutex.Unlock()
 
-	s.Debug(fmt.Sprintf("     push to stack: %.2f", x))
+	s.Debug(fmt.Sprintf("     push to stack: %.2f", item))
 
 	s.Bump()
-	s.linklist.PushBack(x)
+	s.linklist.PushBack(item)
 }
 
 // remove and return an item from the stack
@@ -90,6 +90,7 @@ func (s *Stack) Pop() float64 {
 	s.Debug(fmt.Sprintf(" remove from stack: %.2f", val))
 
 	s.Bump()
+
 	return val.(float64)
 }
 
@@ -123,32 +124,33 @@ func (s *Stack) Swap() {
 		return
 	}
 
-	a := s.linklist.Back()
-	s.linklist.Remove(a)
+	prevA := s.linklist.Back()
+	s.linklist.Remove(prevA)
 
-	b := s.linklist.Back()
-	s.linklist.Remove(b)
+	prevB := s.linklist.Back()
+	s.linklist.Remove(prevB)
 
-	s.Debug(fmt.Sprintf("swapping %.2f with %.2f", b.Value, a.Value))
+	s.Debug(fmt.Sprintf("swapping %.2f with %.2f", prevB.Value, prevA.Value))
 
-	s.linklist.PushBack(a.Value)
-	s.linklist.PushBack(b.Value)
+	s.linklist.PushBack(prevA.Value)
+	s.linklist.PushBack(prevB.Value)
 }
 
 // Return the last num items from the stack w/o modifying it.
 func (s *Stack) Last(num ...int) []float64 {
 	items := []float64{}
-	i := s.Len()
+	stacklen := s.Len()
 	count := 1
+
 	if len(num) > 0 {
 		count = num[0]
 	}
 
 	for e := s.linklist.Front(); e != nil; e = e.Next() {
-		if i <= count {
+		if stacklen <= count {
 			items = append(items, e.Value.(float64))
 		}
-		i--
+		stacklen--
 	}
 
 	return items
@@ -168,12 +170,14 @@ func (s *Stack) All() []float64 {
 // dump the stack to stdout, including backup if debug is enabled
 func (s *Stack) Dump() {
 	fmt.Printf("Stack revision %d (%p):\n", s.rev, &s.linklist)
+
 	for e := s.linklist.Front(); e != nil; e = e.Next() {
 		fmt.Println(e.Value)
 	}
 
 	if s.debug {
 		fmt.Printf("Backup stack revision %d (%p):\n", s.backuprev, &s.backup)
+
 		for e := s.backup.Front(); e != nil; e = e.Next() {
 			fmt.Println(e.Value)
 		}
@@ -195,31 +199,53 @@ func (s *Stack) Backup() {
 	// make a backup, because the elements in list.List{} are pointers
 	// and lead to unexpected  results. The methid here works reliably
 	// at least.
+	s.mutex.Lock()
+	defer s.mutex.Unlock()
+
+	s.Debug(fmt.Sprintf("backing up %d items from rev %d",
+		s.linklist.Len(), s.rev))
+
 	s.backup = list.List{}
 	for e := s.linklist.Front(); e != nil; e = e.Next() {
-		s.backup.PushBack(e.Value)
+		s.backup.PushBack(e.Value.(float64))
 	}
+
 	s.backuprev = s.rev
 }
 
 func (s *Stack) Restore() {
+	s.mutex.Lock()
+	defer s.mutex.Unlock()
+
 	if s.rev == 0 {
 		fmt.Println("error: stack is empty.")
+
 		return
 	}
 
 	s.Debug(fmt.Sprintf("restoring stack to revision %d", s.backuprev))
 
 	s.rev = s.backuprev
-	s.linklist = s.backup
+
+	s.linklist = list.List{}
+	for e := s.backup.Front(); e != nil; e = e.Next() {
+		s.linklist.PushBack(e.Value.(float64))
+	}
 }
 
 func (s *Stack) Reverse() {
-	newstack := list.List{}
+	s.mutex.Lock()
+	defer s.mutex.Unlock()
+
+	items := []float64{}
 
 	for e := s.linklist.Front(); e != nil; e = e.Next() {
-		newstack.PushFront(e.Value)
+		tail := s.linklist.Back()
+		items = append(items, tail.Value.(float64))
+		s.linklist.Remove(tail)
 	}
 
-	s.linklist = newstack
+	for i := len(items) - 1; i >= 0; i-- {
+		s.linklist.PushFront(items[i])
+	}
 }

cmd/stack_test.go

@@ -15,7 +15,7 @@ You should have received a copy of the GNU General Public License
 along with this program. If not, see <http://www.gnu.org/licenses/>.
 */
 
-package main
+package cmd
 
 import (
 	"testing"
@@ -35,16 +35,16 @@ func TestPush(t *testing.T) {
 
 func TestPop(t *testing.T) {
 	t.Run("pop", func(t *testing.T) {
-		s := NewStack()
-		s.Push(5)
-		got := s.Pop()
+		stack := NewStack()
+		stack.Push(5)
+		got := stack.Pop()
 
 		if got != 5.0 {
 			t.Errorf("pop failed:\n+++  got: %f\n--- want: %f",
 				got, 5.0)
 		}
 
-		if s.Len() != 0 {
+		if stack.Len() != 0 {
 			t.Errorf("stack not empty after pop()")
 		}
 	})
@@ -52,25 +52,25 @@ func TestPop(t *testing.T) {
 
 func TestPops(t *testing.T) {
 	t.Run("pops", func(t *testing.T) {
-		s := NewStack()
-		s.Push(5)
-		s.Push(5)
-		s.Push(5)
-		s.Pop()
+		stack := NewStack()
+		stack.Push(5)
+		stack.Push(5)
+		stack.Push(5)
+		stack.Pop()
 
-		if s.Len() != 2 {
+		if stack.Len() != 2 {
 			t.Errorf("stack len not correct after pop:\n+++  got: %d\n--- want: %d",
-				s.Len(), 2)
+				stack.Len(), 2)
 		}
 	})
 }
 
 func TestShift(t *testing.T) {
 	t.Run("shift", func(t *testing.T) {
-		s := NewStack()
-		s.Shift()
+		stack := NewStack()
+		stack.Shift()
 
-		if s.Len() != 0 {
+		if stack.Len() != 0 {
 			t.Errorf("stack not empty after shift()")
 		}
 	})
@@ -78,13 +78,13 @@ func TestShift(t *testing.T) {
 
 func TestClear(t *testing.T) {
 	t.Run("clear", func(t *testing.T) {
-		s := NewStack()
-		s.Push(5)
-		s.Push(5)
-		s.Push(5)
-		s.Clear()
+		stack := NewStack()
+		stack.Push(5)
+		stack.Push(5)
+		stack.Push(5)
+		stack.Clear()
 
-		if s.Len() != 0 {
+		if stack.Len() != 0 {
 			t.Errorf("stack not empty after clear()")
 		}
 	})
@@ -92,9 +92,9 @@ func TestClear(t *testing.T) {
 
 func TestLast(t *testing.T) {
 	t.Run("last", func(t *testing.T) {
-		s := NewStack()
-		s.Push(5)
-		got := s.Last()
+		stack := NewStack()
+		stack.Push(5)
+		got := stack.Last()
 
 		if len(got) != 1 {
 			t.Errorf("last failed:\n+++  got: %d elements\n--- want: %d elements",
@@ -106,7 +106,7 @@ func TestLast(t *testing.T) {
 				got, 5.0)
 		}
 
-		if s.Len() != 1 {
+		if stack.Len() != 1 {
 			t.Errorf("stack modified after last()")
 		}
 	})
@@ -114,14 +114,14 @@ func TestLast(t *testing.T) {
 
 func TestAll(t *testing.T) {
 	t.Run("all", func(t *testing.T) {
-		s := NewStack()
+		stack := NewStack()
 		list := []float64{2, 4, 6, 8}
 
 		for _, item := range list {
-			s.Push(item)
+			stack.Push(item)
 		}
 
-		got := s.All()
+		got := stack.All()
 
 		if len(got) != len(list) {
 			t.Errorf("all failed:\n+++  got: %d elements\n--- want: %d elements",
@@ -135,7 +135,7 @@ func TestAll(t *testing.T) {
 			}
 		}
 
-		if s.Len() != len(list) {
+		if stack.Len() != len(list) {
 			t.Errorf("stack modified after last()")
 		}
 	})
@@ -143,37 +143,37 @@ func TestAll(t *testing.T) {
 
 func TestBackupRestore(t *testing.T) {
 	t.Run("shift", func(t *testing.T) {
-		s := NewStack()
-		s.Push(5)
-		s.Backup()
-		s.Clear()
-		s.Restore()
+		stack := NewStack()
+		stack.Push(5)
+		stack.Backup()
+		stack.Clear()
+		stack.Restore()
 
-		if s.Len() != 1 {
+		if stack.Len() != 1 {
 			t.Errorf("stack not correctly restored()")
 		}
 
-		a := s.Pop()
-		if a != 5.0 {
+		value := stack.Pop()
+		if value != 5.0 {
 			t.Errorf("stack not identical to old revision:\n+++  got: %f\n--- want: %f",
-				a, 5.0)
+				value, 5.0)
 		}
 	})
 }
 
 func TestReverse(t *testing.T) {
 	t.Run("reverse", func(t *testing.T) {
-		s := NewStack()
+		stack := NewStack()
 		list := []float64{2, 4, 6}
 		reverse := []float64{6, 4, 2}
 
 		for _, item := range list {
-			s.Push(item)
+			stack.Push(item)
 		}
 
-		s.Reverse()
+		stack.Reverse()
 
-		got := s.All()
+		got := stack.All()
 
 		if len(got) != len(list) {
 			t.Errorf("all failed:\n+++  got: %d elements\n--- want: %d elements",

cmd/util.go

@@ -15,7 +15,7 @@ You should have received a copy of the GNU General Public License
 along with this program. If not, see <http://www.gnu.org/licenses/>.
 */
 
-package main
+package cmd
 
 import (
 	"fmt"
@@ -23,13 +23,23 @@ import (
 	"strings"
 )
 
-// find an item in a list
-func contains(s []string, e string) bool {
-	for _, a := range s {
-		if a == e {
+// find an item in a list, generic variant
+func contains[E comparable](s []E, v E) bool {
+	for _, vs := range s {
+		if v == vs {
 			return true
 		}
 	}
+
+	return false
+}
+
+// look if a key in a map exists, generic variant
+func exists[K comparable, V any](m map[K]V, v K) bool {
+	if _, ok := m[v]; ok {
+		return true
+	}
+
 	return false
 }
 
@@ -63,3 +73,7 @@ func const2num(name string) float64 {
 func list2str(list Numbers) string {
 	return strings.Trim(strings.Join(strings.Fields(fmt.Sprint(list)), " "), "[]")
 }
+
+func Error(m string) error {
+	return fmt.Errorf("Error: %s", m)
+}

cmd/util_test.go

@@ -15,7 +15,7 @@ You should have received a copy of the GNU General Public License
 along with this program. If not, see <http://www.gnu.org/licenses/>.
 */
 
-package main
+package cmd
 
 import (
 	"testing"

example.lua

@@ -0,0 +1,38 @@
+-- simple function, return the lower number of the two operands
+function lower(a,b)
+    if a < b then
+        return a
+    else
+        return b
+    end
+end
+
+-- calculate parallel resistance. Batch  function (registered with -1,
+-- see below). Takes a table as parameter.
+--
+-- Formula: 1/( (1/R1) + (1/R2) + ...)
+function parallelresistance(list)
+    sumres = 0
+    
+    for i, value in ipairs(list) do
+        sumres = sumres + 1 / value
+    end
+
+    return 1 / sumres
+end
+
+-- converter example
+function inch2centimeter(inches)
+    return inches * 2.54
+end
+
+function init()
+    -- expects 2 args
+    register("lower", 2, "lower")
+
+    -- expects a list of all numbers on the stack, batch mode
+    register("parallelresistance", -1, "parallel resistance")
+
+    -- expects 1 arg, but doesn't pop()
+    register("inch2centimeter", 0)
+end  

funcs.go

@@ -1,460 +0,0 @@
-/*
-Copyright © 2023 Thomas von Dein
-
-This program is free software: you can redistribute it and/or modify
-it under the terms of the GNU General Public License as published by
-the Free Software Foundation, either version 3 of the License, or
-(at your option) any later version.
-
-This program is distributed in the hope that it will be useful,
-but WITHOUT ANY WARRANTY; without even the implied warranty of
-MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-GNU General Public License for more details.
-
-You should have received a copy of the GNU General Public License
-along with this program. If not, see <http://www.gnu.org/licenses/>.
-*/
-
-package main
-
-import (
-	"errors"
-	"math"
-)
-
-type R struct {
-	Res float64
-	Err error
-}
-
-type Numbers []float64
-
-type Function func(Numbers) R
-
-// every function we  are able to call must be  of type Funcall, which
-// needs to  specify how  many numbers  it expects  and the  actual go
-// function to be executed.
-//
-// The function  has to take  a float slice  as argument and  return a
-// float and  an error object. The  float slice is guaranteed  to have
-// the expected number of arguments.
-//
-// However, Lua functions are handled differently, see interpreter.go.
-type Funcall struct {
-	Expectargs int // -1 means batch only mode, you'll get the whole stack as arg
-	Func       Function
-}
-
-// will hold all hard coded functions and operators
-type Funcalls map[string]*Funcall
-
-// convenience function,  create a  new Funcall object,  if expectargs
-// was not specified, 2 is assumed.
-func NewFuncall(function Function, expectargs ...int) *Funcall {
-	expect := 2
-
-	if len(expectargs) > 0 {
-		expect = expectargs[0]
-	}
-
-	return &Funcall{
-		Expectargs: expect,
-		Func:       function,
-	}
-}
-
-// Convenience function, create new result
-func NewR(n float64, e error) R {
-	return R{Res: n, Err: e}
-}
-
-// the actual functions, called once during initialization.
-func DefineFunctions() Funcalls {
-	f := map[string]*Funcall{
-		// simple operators, they all expect 2 args
-		"+": NewFuncall(
-			func(arg Numbers) R {
-				return NewR(arg[0]+arg[1], nil)
-			},
-		),
-
-		"-": NewFuncall(
-			func(arg Numbers) R {
-				return NewR(arg[0]-arg[1], nil)
-			},
-		),
-
-		"x": NewFuncall(
-			func(arg Numbers) R {
-				return NewR(arg[0]*arg[1], nil)
-			},
-		),
-
-		"/": NewFuncall(
-			func(arg Numbers) R {
-				if arg[1] == 0 {
-					return NewR(0, errors.New("division by null"))
-				}
-
-				return NewR(arg[0]/arg[1], nil)
-			},
-		),
-
-		"^": NewFuncall(
-			func(arg Numbers) R {
-				return NewR(math.Pow(arg[0], arg[1]), nil)
-			},
-		),
-
-		"%": NewFuncall(
-			func(arg Numbers) R {
-				return NewR((arg[0]/100)*arg[1], nil)
-			},
-		),
-
-		"%-": NewFuncall(
-			func(arg Numbers) R {
-				return NewR(arg[0]-((arg[0]/100)*arg[1]), nil)
-			},
-		),
-
-		"%+": NewFuncall(
-			func(arg Numbers) R {
-				return NewR(arg[0]+((arg[0]/100)*arg[1]), nil)
-			},
-		),
-
-		"mod": NewFuncall(
-			func(arg Numbers) R {
-				return NewR(math.Remainder(arg[0], arg[1]), nil)
-			},
-		),
-
-		"sqrt": NewFuncall(
-			func(arg Numbers) R {
-				return NewR(math.Sqrt(arg[0]), nil)
-			},
-			1),
-
-		"abs": NewFuncall(
-			func(arg Numbers) R {
-				return NewR(math.Abs(arg[0]), nil)
-			},
-			1),
-
-		"acos": NewFuncall(
-			func(arg Numbers) R {
-				return NewR(math.Acos(arg[0]), nil)
-			},
-			1),
-
-		"acosh": NewFuncall(
-			func(arg Numbers) R {
-				return NewR(math.Acosh(arg[0]), nil)
-			},
-			1),
-
-		"asin": NewFuncall(
-			func(arg Numbers) R {
-				return NewR(math.Asin(arg[0]), nil)
-			},
-			1),
-
-		"asinh": NewFuncall(
-			func(arg Numbers) R {
-				return NewR(math.Asinh(arg[0]), nil)
-			},
-			1),
-
-		"atan": NewFuncall(
-			func(arg Numbers) R {
-				return NewR(math.Atan(arg[0]), nil)
-			},
-			1),
-
-		"atan2": NewFuncall(
-			func(arg Numbers) R {
-				return NewR(math.Atan2(arg[0], arg[1]), nil)
-			},
-			2),
-
-		"atanh": NewFuncall(
-			func(arg Numbers) R {
-				return NewR(math.Atanh(arg[0]), nil)
-			},
-			1),
-
-		"cbrt": NewFuncall(
-			func(arg Numbers) R {
-				return NewR(math.Cbrt(arg[0]), nil)
-			},
-			1),
-
-		"ceil": NewFuncall(
-			func(arg Numbers) R {
-				return NewR(math.Ceil(arg[0]), nil)
-			},
-			1),
-
-		"cos": NewFuncall(
-			func(arg Numbers) R {
-				return NewR(math.Cos(arg[0]), nil)
-			},
-			1),
-
-		"cosh": NewFuncall(
-			func(arg Numbers) R {
-				return NewR(math.Cosh(arg[0]), nil)
-			},
-			1),
-
-		"erf": NewFuncall(
-			func(arg Numbers) R {
-				return NewR(math.Erf(arg[0]), nil)
-			},
-			1),
-
-		"erfc": NewFuncall(
-			func(arg Numbers) R {
-				return NewR(math.Erfc(arg[0]), nil)
-			},
-			1),
-
-		"erfcinv": NewFuncall(
-			func(arg Numbers) R {
-				return NewR(math.Erfcinv(arg[0]), nil)
-			},
-			1),
-
-		"erfinv": NewFuncall(
-			func(arg Numbers) R {
-				return NewR(math.Erfinv(arg[0]), nil)
-			},
-			1),
-
-		"exp": NewFuncall(
-			func(arg Numbers) R {
-				return NewR(math.Exp(arg[0]), nil)
-			},
-			1),
-
-		"exp2": NewFuncall(
-			func(arg Numbers) R {
-				return NewR(math.Exp2(arg[0]), nil)
-			},
-			1),
-
-		"expm1": NewFuncall(
-			func(arg Numbers) R {
-				return NewR(math.Expm1(arg[0]), nil)
-			},
-			1),
-
-		"floor": NewFuncall(
-			func(arg Numbers) R {
-				return NewR(math.Floor(arg[0]), nil)
-			},
-			1),
-
-		"gamma": NewFuncall(
-			func(arg Numbers) R {
-				return NewR(math.Gamma(arg[0]), nil)
-			},
-			1),
-
-		"ilogb": NewFuncall(
-			func(arg Numbers) R {
-				return NewR(float64(math.Ilogb(arg[0])), nil)
-			},
-			1),
-
-		"j0": NewFuncall(
-			func(arg Numbers) R {
-				return NewR(math.J0(arg[0]), nil)
-			},
-			1),
-
-		"j1": NewFuncall(
-			func(arg Numbers) R {
-				return NewR(math.J1(arg[0]), nil)
-			},
-			1),
-
-		"log": NewFuncall(
-			func(arg Numbers) R {
-				return NewR(math.Log(arg[0]), nil)
-			},
-			1),
-
-		"log10": NewFuncall(
-			func(arg Numbers) R {
-				return NewR(math.Log10(arg[0]), nil)
-			},
-			1),
-
-		"log1p": NewFuncall(
-			func(arg Numbers) R {
-				return NewR(math.Log1p(arg[0]), nil)
-			},
-			1),
-
-		"log2": NewFuncall(
-			func(arg Numbers) R {
-				return NewR(math.Log2(arg[0]), nil)
-			},
-			1),
-
-		"logb": NewFuncall(
-			func(arg Numbers) R {
-				return NewR(math.Logb(arg[0]), nil)
-			},
-			1),
-
-		"pow": NewFuncall(
-			func(arg Numbers) R {
-				return NewR(math.Pow(arg[0], arg[1]), nil)
-			},
-			2),
-
-		"round": NewFuncall(
-			func(arg Numbers) R {
-				return NewR(math.Round(arg[0]), nil)
-			},
-			1),
-
-		"roundtoeven": NewFuncall(
-			func(arg Numbers) R {
-				return NewR(math.RoundToEven(arg[0]), nil)
-			},
-			1),
-
-		"sin": NewFuncall(
-			func(arg Numbers) R {
-				return NewR(math.Sin(arg[0]), nil)
-			},
-			1),
-
-		"sinh": NewFuncall(
-			func(arg Numbers) R {
-				return NewR(math.Sinh(arg[0]), nil)
-			},
-			1),
-
-		"tan": NewFuncall(
-			func(arg Numbers) R {
-				return NewR(math.Tan(arg[0]), nil)
-			},
-			1),
-
-		"tanh": NewFuncall(
-			func(arg Numbers) R {
-				return NewR(math.Tanh(arg[0]), nil)
-			},
-			1),
-
-		"trunc": NewFuncall(
-			func(arg Numbers) R {
-				return NewR(math.Trunc(arg[0]), nil)
-			},
-			1),
-
-		"y0": NewFuncall(
-			func(arg Numbers) R {
-				return NewR(math.Y0(arg[0]), nil)
-			},
-			1),
-
-		"y1": NewFuncall(
-			func(arg Numbers) R {
-				return NewR(math.Y1(arg[0]), nil)
-			},
-			1),
-
-		"copysign": NewFuncall(
-			func(arg Numbers) R {
-				return NewR(math.Copysign(arg[0], arg[1]), nil)
-			},
-			2),
-
-		"dim": NewFuncall(
-			func(arg Numbers) R {
-				return NewR(math.Dim(arg[0], arg[1]), nil)
-			},
-			2),
-
-		"hypot": NewFuncall(
-			func(arg Numbers) R {
-				return NewR(math.Hypot(arg[0], arg[1]), nil)
-			},
-			2),
-	}
-
-	// aliases
-	f["*"] = f["x"]
-	f["remainder"] = f["mod"]
-
-	return f
-}
-
-func DefineBatchFunctions() Funcalls {
-	f := map[string]*Funcall{
-		"median": NewFuncall(
-			func(args Numbers) R {
-				middle := len(args) / 2
-				return NewR(args[middle], nil)
-			},
-			-1),
-
-		"mean": NewFuncall(
-			func(args Numbers) R {
-				var sum float64
-				for _, item := range args {
-					sum += item
-				}
-				return NewR(sum/float64(len(args)), nil)
-			},
-			-1),
-
-		"min": NewFuncall(
-			func(args Numbers) R {
-				var min float64
-				min, args = args[0], args[1:]
-				for _, item := range args {
-					if item < min {
-						min = item
-					}
-				}
-				return NewR(min, nil)
-			},
-			-1),
-
-		"max": NewFuncall(
-			func(args Numbers) R {
-				var max float64
-				max, args = args[0], args[1:]
-				for _, item := range args {
-					if item > max {
-						max = item
-					}
-				}
-				return NewR(max, nil)
-			},
-			-1),
-
-		"sum": NewFuncall(
-			func(args Numbers) R {
-				var sum float64
-				for _, item := range args {
-					sum += item
-				}
-				return NewR(sum, nil)
-			},
-			-1),
-	}
-
-	// aliases
-	f["+"] = f["sum"]
-	f["avg"] = f["mean"]
-
-	return f
-}

go.mod

@@ -1,10 +1,34 @@
 module rpn
 
-go 1.20
+go 1.24.5
 
 require (
-	github.com/chzyer/readline v1.5.1 // indirect
-	github.com/spf13/pflag v1.0.5 // indirect
-	github.com/yuin/gopher-lua v1.1.0 // indirect
-	golang.org/x/sys v0.0.0-20220310020820-b874c991c1a5 // indirect
+	github.com/charmbracelet/bubbles v0.21.0
+	github.com/charmbracelet/bubbletea v1.3.10
+	github.com/charmbracelet/lipgloss v1.1.0
+	github.com/chzyer/readline v1.5.1
+	github.com/rogpeppe/go-internal v1.14.1
+	github.com/spf13/pflag v1.0.10
+	github.com/yuin/gopher-lua v1.1.1
+)
+
+require (
+	github.com/aymanbagabas/go-osc52/v2 v2.0.1 // indirect
+	github.com/charmbracelet/colorprofile v0.2.3-0.20250311203215-f60798e515dc // indirect
+	github.com/charmbracelet/x/ansi v0.10.1 // indirect
+	github.com/charmbracelet/x/cellbuf v0.0.13-0.20250311204145-2c3ea96c31dd // indirect
+	github.com/charmbracelet/x/term v0.2.1 // indirect
+	github.com/erikgeiser/coninput v0.0.0-20211004153227-1c3628e74d0f // indirect
+	github.com/lucasb-eyer/go-colorful v1.2.0 // indirect
+	github.com/mattn/go-isatty v0.0.20 // indirect
+	github.com/mattn/go-localereader v0.0.1 // indirect
+	github.com/mattn/go-runewidth v0.0.16 // indirect
+	github.com/muesli/ansi v0.0.0-20230316100256-276c6243b2f6 // indirect
+	github.com/muesli/cancelreader v0.2.2 // indirect
+	github.com/muesli/termenv v0.16.0 // indirect
+	github.com/rivo/uniseg v0.4.7 // indirect
+	github.com/xo/terminfo v0.0.0-20220910002029-abceb7e1c41e // indirect
+	golang.org/x/sys v0.36.0 // indirect
+	golang.org/x/text v0.3.8 // indirect
+	golang.org/x/tools v0.26.0 // indirect
 )

go.sum

@@ -1,10 +1,60 @@
+github.com/aymanbagabas/go-osc52/v2 v2.0.1 h1:HwpRHbFMcZLEVr42D4p7XBqjyuxQH5SMiErDT4WkJ2k=
+github.com/aymanbagabas/go-osc52/v2 v2.0.1/go.mod h1:uYgXzlJ7ZpABp8OJ+exZzJJhRNQ2ASbcXHWsFqH8hp8=
+github.com/charmbracelet/bubbles v0.21.0 h1:9TdC97SdRVg/1aaXNVWfFH3nnLAwOXr8Fn6u6mfQdFs=
+github.com/charmbracelet/bubbles v0.21.0/go.mod h1:HF+v6QUR4HkEpz62dx7ym2xc71/KBHg+zKwJtMw+qtg=
+github.com/charmbracelet/bubbletea v1.3.10 h1:otUDHWMMzQSB0Pkc87rm691KZ3SWa4KUlvF9nRvCICw=
+github.com/charmbracelet/bubbletea v1.3.10/go.mod h1:ORQfo0fk8U+po9VaNvnV95UPWA1BitP1E0N6xJPlHr4=
+github.com/charmbracelet/colorprofile v0.2.3-0.20250311203215-f60798e515dc h1:4pZI35227imm7yK2bGPcfpFEmuY1gc2YSTShr4iJBfs=
+github.com/charmbracelet/colorprofile v0.2.3-0.20250311203215-f60798e515dc/go.mod h1:X4/0JoqgTIPSFcRA/P6INZzIuyqdFY5rm8tb41s9okk=
+github.com/charmbracelet/lipgloss v1.1.0 h1:vYXsiLHVkK7fp74RkV7b2kq9+zDLoEU4MZoFqR/noCY=
+github.com/charmbracelet/lipgloss v1.1.0/go.mod h1:/6Q8FR2o+kj8rz4Dq0zQc3vYf7X+B0binUUBwA0aL30=
+github.com/charmbracelet/x/ansi v0.10.1 h1:rL3Koar5XvX0pHGfovN03f5cxLbCF2YvLeyz7D2jVDQ=
+github.com/charmbracelet/x/ansi v0.10.1/go.mod h1:3RQDQ6lDnROptfpWuUVIUG64bD2g2BgntdxH0Ya5TeE=
+github.com/charmbracelet/x/cellbuf v0.0.13-0.20250311204145-2c3ea96c31dd h1:vy0GVL4jeHEwG5YOXDmi86oYw2yuYUGqz6a8sLwg0X8=
+github.com/charmbracelet/x/cellbuf v0.0.13-0.20250311204145-2c3ea96c31dd/go.mod h1:xe0nKWGd3eJgtqZRaN9RjMtK7xUYchjzPr7q6kcvCCs=
+github.com/charmbracelet/x/term v0.2.1 h1:AQeHeLZ1OqSXhrAWpYUtZyX1T3zVxfpZuEQMIQaGIAQ=
+github.com/charmbracelet/x/term v0.2.1/go.mod h1:oQ4enTYFV7QN4m0i9mzHrViD7TQKvNEEkHUMCmsxdUg=
+github.com/chzyer/logex v1.2.1 h1:XHDu3E6q+gdHgsdTPH6ImJMIp436vR6MPtH8gP05QzM=
 github.com/chzyer/logex v1.2.1/go.mod h1:JLbx6lG2kDbNRFnfkgvh4eRJRPX1QCoOIWomwysCBrQ=
 github.com/chzyer/readline v1.5.1 h1:upd/6fQk4src78LMRzh5vItIt361/o4uq553V8B5sGI=
 github.com/chzyer/readline v1.5.1/go.mod h1:Eh+b79XXUwfKfcPLepksvw2tcLE/Ct21YObkaSkeBlk=
+github.com/chzyer/test v1.0.0 h1:p3BQDXSxOhOG0P9z6/hGnII4LGiEPOYBhs8asl/fC04=
 github.com/chzyer/test v1.0.0/go.mod h1:2JlltgoNkt4TW/z9V/IzDdFaMTM2JPIi26O1pF38GC8=
-github.com/spf13/pflag v1.0.5 h1:iy+VFUOCP1a+8yFto/drg2CJ5u0yRoB7fZw3DKv/JXA=
-github.com/spf13/pflag v1.0.5/go.mod h1:McXfInJRrz4CZXVZOBLb0bTZqETkiAhM9Iw0y3An2Bg=
-github.com/yuin/gopher-lua v1.1.0 h1:BojcDhfyDWgU2f2TOzYK/g5p2gxMrku8oupLDqlnSqE=
-github.com/yuin/gopher-lua v1.1.0/go.mod h1:GBR0iDaNXjAgGg9zfCvksxSRnQx76gclCIb7kdAd1Pw=
-golang.org/x/sys v0.0.0-20220310020820-b874c991c1a5 h1:y/woIyUBFbpQGKS0u1aHF/40WUDnek3fPOyD08H5Vng=
+github.com/erikgeiser/coninput v0.0.0-20211004153227-1c3628e74d0f h1:Y/CXytFA4m6baUTXGLOoWe4PQhGxaX0KpnayAqC48p4=
+github.com/erikgeiser/coninput v0.0.0-20211004153227-1c3628e74d0f/go.mod h1:vw97MGsxSvLiUE2X8qFplwetxpGLQrlU1Q9AUEIzCaM=
+github.com/lucasb-eyer/go-colorful v1.2.0 h1:1nnpGOrhyZZuNyfu1QjKiUICQ74+3FNCN69Aj6K7nkY=
+github.com/lucasb-eyer/go-colorful v1.2.0/go.mod h1:R4dSotOR9KMtayYi1e77YzuveK+i7ruzyGqttikkLy0=
+github.com/mattn/go-isatty v0.0.20 h1:xfD0iDuEKnDkl03q4limB+vH+GxLEtL/jb4xVJSWWEY=
+github.com/mattn/go-isatty v0.0.20/go.mod h1:W+V8PltTTMOvKvAeJH7IuucS94S2C6jfK/D7dTCTo3Y=
+github.com/mattn/go-localereader v0.0.1 h1:ygSAOl7ZXTx4RdPYinUpg6W99U8jWvWi9Ye2JC/oIi4=
+github.com/mattn/go-localereader v0.0.1/go.mod h1:8fBrzywKY7BI3czFoHkuzRoWE9C+EiG4R1k4Cjx5p88=
+github.com/mattn/go-runewidth v0.0.16 h1:E5ScNMtiwvlvB5paMFdw9p4kSQzbXFikJ5SQO6TULQc=
+github.com/mattn/go-runewidth v0.0.16/go.mod h1:Jdepj2loyihRzMpdS35Xk/zdY8IAYHsh153qUoGf23w=
+github.com/muesli/ansi v0.0.0-20230316100256-276c6243b2f6 h1:ZK8zHtRHOkbHy6Mmr5D264iyp3TiX5OmNcI5cIARiQI=
+github.com/muesli/ansi v0.0.0-20230316100256-276c6243b2f6/go.mod h1:CJlz5H+gyd6CUWT45Oy4q24RdLyn7Md9Vj2/ldJBSIo=
+github.com/muesli/cancelreader v0.2.2 h1:3I4Kt4BQjOR54NavqnDogx/MIoWBFa0StPA8ELUXHmA=
+github.com/muesli/cancelreader v0.2.2/go.mod h1:3XuTXfFS2VjM+HTLZY9Ak0l6eUKfijIfMUZ4EgX0QYo=
+github.com/muesli/termenv v0.16.0 h1:S5AlUN9dENB57rsbnkPyfdGuWIlkmzJjbFf0Tf5FWUc=
+github.com/muesli/termenv v0.16.0/go.mod h1:ZRfOIKPFDYQoDFF4Olj7/QJbW60Ol/kL1pU3VfY/Cnk=
+github.com/rivo/uniseg v0.2.0/go.mod h1:J6wj4VEh+S6ZtnVlnTBMWIodfgj8LQOQFoIToxlJtxc=
+github.com/rivo/uniseg v0.4.7 h1:WUdvkW8uEhrYfLC4ZzdpI2ztxP1I582+49Oc5Mq64VQ=
+github.com/rivo/uniseg v0.4.7/go.mod h1:FN3SvrM+Zdj16jyLfmOkMNblXMcoc8DfTHruCPUcx88=
+github.com/rogpeppe/go-internal v1.14.1 h1:UQB4HGPB6osV0SQTLymcB4TgvyWu6ZyliaW0tI/otEQ=
+github.com/rogpeppe/go-internal v1.14.1/go.mod h1:MaRKkUm5W0goXpeCfT7UZI6fk/L7L7so1lCWt35ZSgc=
+github.com/spf13/pflag v1.0.10 h1:4EBh2KAYBwaONj6b2Ye1GiHfwjqyROoF4RwYO+vPwFk=
+github.com/spf13/pflag v1.0.10/go.mod h1:McXfInJRrz4CZXVZOBLb0bTZqETkiAhM9Iw0y3An2Bg=
+github.com/xo/terminfo v0.0.0-20220910002029-abceb7e1c41e h1:JVG44RsyaB9T2KIHavMF/ppJZNG9ZpyihvCd0w101no=
+github.com/xo/terminfo v0.0.0-20220910002029-abceb7e1c41e/go.mod h1:RbqR21r5mrJuqunuUZ/Dhy/avygyECGrLceyNeo4LiM=
+github.com/yuin/gopher-lua v1.1.1 h1:kYKnWBjvbNP4XLT3+bPEwAXJx262OhaHDWDVOPjL46M=
+github.com/yuin/gopher-lua v1.1.1/go.mod h1:GBR0iDaNXjAgGg9zfCvksxSRnQx76gclCIb7kdAd1Pw=
+golang.org/x/exp v0.0.0-20220909182711-5c715a9e8561 h1:MDc5xs78ZrZr3HMQugiXOAkSZtfTpbJLDr/lwfgO53E=
+golang.org/x/exp v0.0.0-20220909182711-5c715a9e8561/go.mod h1:cyybsKvd6eL0RnXn6p/Grxp8F5bW7iYuBgsNCOHpMYE=
+golang.org/x/sys v0.0.0-20210809222454-d867a43fc93e/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
 golang.org/x/sys v0.0.0-20220310020820-b874c991c1a5/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
+golang.org/x/sys v0.6.0/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
+golang.org/x/sys v0.36.0 h1:KVRy2GtZBrk1cBYA7MKu5bEZFxQk4NIDV6RLVcC8o0k=
+golang.org/x/sys v0.36.0/go.mod h1:OgkHotnGiDImocRcuBABYBEXf8A9a87e/uXjp9XT3ks=
+golang.org/x/text v0.3.8 h1:nAL+RVCQ9uMn3vJZbV+MRnydTJFPf8qqY42YiA6MrqY=
+golang.org/x/text v0.3.8/go.mod h1:E6s5w1FMmriuDzIBO73fBruAKo1PCIq6d2Q6DHfQ8WQ=
+golang.org/x/tools v0.26.0 h1:v/60pFQmzmT9ExmjDv2gGIfi3OqfKoEP6I5+umXlbnQ=
+golang.org/x/tools v0.26.0/go.mod h1:TPVVj70c7JJ3WCazhD8OdXcZg/og+b9+tH/KxylGwH0=

main.go

@@ -1,5 +1,5 @@
 /*
-Copyright © 2023 Thomas von Dein
+Copyright © 2023-2024 Thomas von Dein
 
 This program is free software: you can redistribute it and/or modify
 it under the terms of the GNU General Public License as published by
@@ -18,159 +18,10 @@ along with this program. If not, see <http://www.gnu.org/licenses/>.
 package main
 
 import (
-	"bytes"
-	"fmt"
-	"log"
 	"os"
-	"os/exec"
-	"strings"
-
-	"github.com/chzyer/readline"
-	flag "github.com/spf13/pflag"
-	lua "github.com/yuin/gopher-lua"
+	"rpn/cmd"
 )
 
-const VERSION string = "2.0.5"
-
-const Usage string = `This is rpn, a reverse polish notation calculator cli.
-
-Usage: rpn [-bdvh] [<operator>]
-
-Options:
-  -b, --batchmode     enable batch mode
-  -d, --debug         enable debug mode
-  -s, --stack         show last 5 items of the stack (off by default)
-  -i  --intermediate  print intermediate results
-  -m, --manual        show manual
-  -v, --version       show version
-  -h, --help          show help
-
-When <operator>  is given, batch  mode ist automatically  enabled. Use
-this only when working with stdin. E.g.: echo "2 3 4 5" | rpn +
-
-Copyright (c) 2023 T.v.Dein`
-
 func main() {
-	calc := NewCalc()
-
-	showversion := false
-	showhelp := false
-	showmanual := false
-	enabledebug := false
-	configfile := ""
-
-	flag.BoolVarP(&calc.batch, "batchmode", "b", false, "batch mode")
-	flag.BoolVarP(&calc.showstack, "show-stack", "s", false, "show stack")
-	flag.BoolVarP(&calc.intermediate, "showin-termediate", "i", false,
-		"show intermediate results")
-	flag.BoolVarP(&enabledebug, "debug", "d", false, "debug mode")
-	flag.BoolVarP(&showversion, "version", "v", false, "show version")
-	flag.BoolVarP(&showhelp, "help", "h", false, "show usage")
-	flag.BoolVarP(&showmanual, "manual", "m", false, "show manual")
-	flag.StringVarP(&configfile, "config", "c",
-		os.Getenv("HOME")+"/.rpn.lua", "config file (lua format)")
-
-	flag.Parse()
-
-	if showversion {
-		fmt.Printf("This is rpn version %s\n", VERSION)
-		return
-	}
-
-	if showhelp {
-		fmt.Println(Usage)
-		return
-	}
-
-	if enabledebug {
-		calc.ToggleDebug()
-	}
-
-	if showmanual {
-		man()
-		os.Exit(0)
-	}
-
-	// the lua state object is global, instanciate it early
-	L = lua.NewState(lua.Options{SkipOpenLibs: true})
-	defer L.Close()
-
-	// our config file is interpreted  as lua code, only functions can
-	// be defined, init() will be called by InitLua().
-	if _, err := os.Stat(configfile); err == nil {
-		I := InitLua(configfile, enabledebug)
-		calc.SetInt(I)
-	}
-
-	if len(flag.Args()) > 1 {
-		// commandline calc operation, no readline etc needed
-		// called like rpn 2 2 +
-		calc.stdin = true
-		calc.Eval(strings.Join(flag.Args(), " "))
-		return
-	}
-
-	// interactive mode, need readline
-	rl, err := readline.NewEx(&readline.Config{
-		Prompt:            calc.Prompt(),
-		HistoryFile:       os.Getenv("HOME") + "/.rpn-history",
-		HistoryLimit:      500,
-		AutoComplete:      calc.completer,
-		InterruptPrompt:   "^C",
-		EOFPrompt:         "exit",
-		HistorySearchFold: true,
-	})
-
-	if err != nil {
-		panic(err)
-	}
-	defer rl.Close()
-	rl.CaptureExitSignal()
-
-	if inputIsStdin() {
-		// commands are  coming on stdin, however we  will still enter
-		// the same loop since readline just reads fine from stdin
-		calc.ToggleStdin()
-	}
-
-	for {
-		// primary program repl
-		line, err := rl.Readline()
-		if err != nil {
-			break
-		}
-
-		calc.Eval(line)
-		rl.SetPrompt(calc.Prompt())
-	}
-
-	if len(flag.Args()) > 0 {
-		// called like this:
-		// echo 1 2 3 4 | rpn +
-		// batch mode enabled automatically
-		calc.batch = true
-		calc.Eval(flag.Args()[0])
-	}
-}
-
-func inputIsStdin() bool {
-	stat, _ := os.Stdin.Stat()
-	return (stat.Mode() & os.ModeCharDevice) == 0
-}
-
-func man() {
-	man := exec.Command("less", "-")
-
-	var b bytes.Buffer
-	b.Write([]byte(manpage))
-
-	man.Stdout = os.Stdout
-	man.Stdin = &b
-	man.Stderr = os.Stderr
-
-	err := man.Run()
-
-	if err != nil {
-		log.Fatal(err)
-	}
+	os.Exit(cmd.Main())
 }

main_test.go

@@ -0,0 +1,19 @@
+package main
+
+import (
+	"testing"
+
+	"github.com/rogpeppe/go-internal/testscript"
+)
+
+func TestMain(m *testing.M) {
+	testscript.Main(m, map[string]func(){
+		"rpn": main,
+	})
+}
+
+func TestRpn(t *testing.T) {
+	testscript.Run(t, testscript.Params{
+		Dir: "t",
+	})
+}

mkrel.sh

@@ -1,65 +0,0 @@
-#!/bin/bash
-
-# Copyright © 2023 Thomas von Dein
-
-# This program is free software: you can redistribute it and/or modify
-# it under the terms of the GNU General Public License as published by
-# the Free Software Foundation, either version 3 of the License, or
-# (at your option) any later version.
-
-# This program is distributed in the hope that it will be useful,
-# but WITHOUT ANY WARRANTY; without even the implied warranty of
-# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-# GNU General Public License for more details.
-
-# You should have received a copy of the GNU General Public License
-# along with this program. If not, see <http://www.gnu.org/licenses/>.
-
-
-# get list with: go tool dist list
-DIST="darwin/amd64
-freebsd/amd64
-linux/amd64
-netbsd/amd64
-openbsd/amd64
-windows/amd64"
-
-tool="$1"
-version="$2"
-
-if test -z "$version"; then
-  echo "Usage: $0 <tool name> <release version>"
-  exit 1
-fi
-
-rm -rf releases
-mkdir -p releases
-
-
-for D in $DIST; do
-    os=${D/\/*/}
-    arch=${D/*\//}
-    binfile="releases/${tool}-${os}-${arch}-${version}"
-    tardir="${tool}-${os}-${arch}-${version}"
-    tarfile="releases/${tool}-${os}-${arch}-${version}.tar.gz"
-    set -x
-    GOOS=${os} GOARCH=${arch} go build -tags osusergo,netgo -ldflags "-extldflags=-static" -o ${binfile}
-    mkdir -p ${tardir}
-    cp ${binfile} README.md LICENSE ${tardir}/
-    echo 'tool = rpn
-PREFIX = /usr/local
-UID    = root
-GID    = 0
-
-install:
-	install -d -o $(UID) -g $(GID) $(PREFIX)/bin
-	install -d -o $(UID) -g $(GID) $(PREFIX)/man/man1
-	install -o $(UID) -g $(GID) -m 555 $(tool)  $(PREFIX)/sbin/
-	install -o $(UID) -g $(GID) -m 444 $(tool).1 $(PREFIX)/man/man1/' > ${tardir}/Makefile
-    tar cpzf ${tarfile} ${tardir}
-    sha256sum ${binfile} | cut -d' ' -f1 > ${binfile}.sha256
-    sha256sum ${tarfile} | cut -d' ' -f1 > ${tarfile}.sha256
-    rm -rf ${tardir}
-    set +x
-done
-

rpn.pod

@@ -7,13 +7,15 @@ rpn - Programmable command-line calculator using reverse polish notation
     Usage: rpn [-bdvh] [<operator>]
     
     Options:
-      -b, --batchmode     enable batch mode
-      -d, --debug         enable debug mode
-      -s, --stack         show last 5 items of the stack (off by default)
-      -i  --intermediate  print intermediate results
-      -m, --manual        show manual
-      -v, --version       show version
-      -h, --help          show help
+      -b, --batchmode       enable batch mode
+      -d, --debug           enable debug mode
+      -s, --stack           show last 5 items of the stack (off by default)
+      -i  --intermediate    print intermediate results
+      -m, --manual          show manual
+      -c, --config <file>   load <file> containing LUA code
+      -p, --precision <int> floating point number precision (default 2)
+      -v, --version         show version
+      -h, --help            show help
     
     When <operator>  is given, batch  mode ist automatically  enabled. Use
     this only when working with stdin. E.g.: echo "2 3 4 5" | rpn +
@@ -109,6 +111,10 @@ Example of batch mode usage:
 If the first parameter to rpn is a math operator or function, batch
 mode is enabled automatically, see last example.
 
+You can enter integers, floating  point numbers (positive or negative)
+or hex  numbers (prefixed with 0x).  Time values in hh::mm  format are
+possible as well.
+
 =head2 STACK MANIPULATION
 
 There are lots of stack manipulation commands provided. The most
@@ -131,15 +137,23 @@ stack.
 Basic operators:
 
     +                    add
-    -                    substract
+    -                    subtract
     /                    divide
     x                    multiply (alias: *)
     ^                    power
 
+Bitwise operators:
+
+    and                  bitwise and
+    or                   bitwise or
+    xor                  bitwise xor
+    <                    left shift
+    >                    right shift
+
 Percent functions:
 
     %                    percent
-    %-                   substract percent
+    %-                   subtract percent
     %+                   add percent
 
 Batch functions:
@@ -157,18 +171,40 @@ Math functions:
     log10 log1p log2 logb pow round roundtoeven sin sinh tan tanh trunc y0
     y1 copysign dim hypot
 
-Commands:
+Conversion functions:
+
+    cm-to-inch          yards-to-meters         bytes-to-kilobytes
+    inch-to-cm          meters-to-yards         bytes-to-megabytes
+    gallons-to-liters   miles-to-kilometers     bytes-to-gigabytes
+    liters-to-gallons   kilometers-to-miles     bytes-to-terabytes
+
+Configuration Commands:
+
+    [no]batch            toggle batch mode (nobatch turns it off)
+    [no]debug            toggle debug output (nodebug turns it off)
+    [no]showstack        show the last 5 items of the stack (noshowtack turns it off)
+
+Show commands:
 
-    batch                toggle batch mode
-    debug                toggle debug output
     dump                 display the stack contents
+    hex                  show last stack item in hex form (converted to int)
+    history              display calculation history
+    vars                 show list of variables
+
+Stack manipulation commands:
+
     clear                clear the whole stack
     shift                remove the last element of the stack
     reverse              reverse the stack elements
     swap                 exchange the last two stack elements
-    show                 show the last 5 items of the stack
-    history              display calculation history
+    dup                  duplicate last stack item
+    undo                 undo last operation
+    edit                 edit the stack interactively using vi or $EDITOR
+
+Other commands:
+
     help|?               show this message
+    manual               show manual
     quit|exit|c-d|c-c    exit program
 
 
@@ -179,6 +215,17 @@ Register variables:
 
 Refer to https://pkg.go.dev/math for details about those functions.
 
+There are also a number of shortcuts for some commands available:
+
+    d    debug
+    b    batch
+    s    showstack
+    h    history
+    p    dump (aka print)
+    v    vars
+    c    clear
+    u    undo
+
 =head1 INTERACTIVE REPL
 
 While you can use rpn in the command-line, the best experience you'll
@@ -273,8 +320,13 @@ function name
 
 =item *
 
-number of arguments expected (1,2 or -1 allowed), -1 means batch
-mode.
+number of arguments expected (see below)
+
+Number of expected arguments can be:
+
+    - 0: expect 1 argument but do NOT modify the stack
+    - 1-n: do a singular calculation
+    - -1: batch mode work with all numbers on the stack 
 
 =item *
 
@@ -289,6 +341,16 @@ B<Please note, that io, networking and system stuff is not allowed
 though. So you can't open files, execute other programs or open a
 connection to the outside!>
 
+=head1 CONFIGURATION
+
+B<rpn> can be configured via command line flags (see usage
+above). Most of the flags are also available as interactive commands,
+such as C<--batch> has the same effect as the B<batch> command.
+
+The floating point number  precision option C<-p, --precision> however
+is not available as interactive command,  it MUST be configured on the
+command line, if needed. The default precision is 2.
+
 =head1 GETTING HELP
 
 In interactive mode you can enter the B<help> command (or B<?>) to get
@@ -305,13 +367,13 @@ tarball, there will also be a manual page you can read using C<man rpn>.
 
 In order to report a bug, unexpected behavior, feature requests
 or to submit a patch, please open an issue on github:
-L<https://github.com/TLINDEN/rpnc/issues>.
+L<https://codeberg.org/scip/rpnc/issues>.
 
 =head1 LICENSE
 
 This software is licensed under the GNU GENERAL PUBLIC LICENSE version 3.
 
-Copyright (c) 2023 by Thomas von Dein
+Copyright (c) 2023-2024 by Thomas von Dein
 
 This software uses the following GO modules:
 

t/cmdline-command.txtar

@@ -0,0 +1,2 @@
+exec rpn 1 2 dump
+stdout 'Stack revision 2 .0x'

t/cmdline-invalidcommand.txtar

@@ -0,0 +1,2 @@
+! exec rpn 1 2 dumb
+stdout 'unknown command or operator'

t/cmdline-precision.txtar

@@ -0,0 +1,2 @@
+exec rpn -p 4 2 3 /
+stdout '0.6667\n'

t/cmdline-short-stack.txtar

@@ -0,0 +1,2 @@
+! exec rpn 4 +
+stdout 'stack doesn''t provide enough arguments'

t/cmdlinecalc-debug.txtar

@@ -0,0 +1,2 @@
+exec rpn -d 44 55 *
+stdout 'push to stack: 2420.00\n'

t/cmdlinecalc-divzero.txtar

@@ -0,0 +1,2 @@
+! exec rpn 100 50 50 - /
+stdout 'division by null'

t/cmdlinecalc-lua.txtar

@@ -0,0 +1,16 @@
+exec rpn -d -c test.lua 3 5 lower
+stdout '3\n'
+
+-- test.lua --
+function lower(a,b)
+    if a < b then
+        return a
+    else
+        return b
+    end
+end
+
+function init()
+    -- expects 2 args
+    register("lower", 2, "lower")
+end

t/cmdlinecalc-time.txtar

@@ -0,0 +1,2 @@
+exec rpn 09:55 4:15 -
+stdout '5.67\n'

t/cmdlinecalc.txtar

@@ -0,0 +1,2 @@
+exec rpn 44 55 *
+stdout '2420\n'

t/getusage.txtar

@@ -0,0 +1,2 @@
+exec rpn -h
+stdout 'This is rpn'

t/getversion.txtar

@@ -0,0 +1,2 @@
+exec rpn -v
+stdout 'This is rpn version'

t/stdin-batch-cmd.txtar

@@ -0,0 +1,4 @@
+exec echo 1 2 3 4 5 batch median
+stdin stdout
+exec rpn
+[unix] stdout '3\n'

t/stdin-batch.txtar

@@ -0,0 +1,4 @@
+exec echo 1 2 3 4 5
+stdin stdout
+[unix] exec rpn median
+[unix] stdout '3\n'

t/stdin-calc.txtar

@@ -0,0 +1,4 @@
+exec echo 10 10 +
+stdin stdout
+exec rpn
+[unix] stdout '20\n'

t/stdin-use-vars.txtar

@@ -0,0 +1,13 @@
+stdin input.txt
+exec rpn
+[unix] stdout '28\n'
+
+-- input.txt --
+10
+10
++
+>SUM
+clear
+8
+<SUM
++

t/stdint-explicit-batch.txtar

@@ -0,0 +1,4 @@
+exec echo 1 2 3 4 5 median
+stdin stdout
+exec rpn -b
+[unix] stdout '3\n'

t/test.lua

@@ -0,0 +1,13 @@
+-- simple function, return the lower number of the two operands
+function lower(a,b)
+    if a < b then
+        return a
+    else
+        return b
+    end
+end
+
+function init()
+    -- expects 2 args
+    register("lower", 2, "lower")
+end  

test.lua

@@ -1,17 +0,0 @@
-function add(a,b)
-  return a + b
-end
-
-function test(a)
-  return a
-end  
-
-function parallelresistance(a,b)
-  return 1.0 / (a * b)
-end
-
-function init()
-  register("add", 2, "addition")
-  register("test", 1, "test")
-  register("parallelresistance", 2, "parallel resistance")
-end