added video explanation (#1)

* added video explanation

.github/ISSUE_TEMPLATE/bug_report.md

@@ -0,0 +1,31 @@
+---
+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

@@ -0,0 +1,23 @@
+---
+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/workflows/ci.yaml

@@ -0,0 +1,36 @@
+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

.gitignore

@@ -1,3 +1,4 @@
 releases
 rpn
 rpn.1
+coverage.out

Makefile

@@ -39,10 +39,6 @@ ifdef HAVE_POD
 	  echo "var manpage = \`" >> $*.go
 	  pod2text $*.pod >> $*.go
 	  echo "\`" >> $*.go
-
-	  echo "var usage = \`" >> $*.go
-	  awk '/SYNOPS/{f=1;next} /DESCR/{f=0} f' $*.pod  | sed 's/^    //' >> $*.go
-	  echo "\`" >> $*.go
 endif
 
 buildlocal:
@@ -59,7 +55,6 @@ clean:
 
 test:
 	go test -v ./...
-	bash t/test.sh
 
 singletest:
 	@echo "Call like this: ''make singletest TEST=TestPrepareColumns MOD=lib"
@@ -77,3 +72,15 @@ buildall:
 
 release: buildall
 	gh release create v$(VERSION) --generate-notes releases/*
+
+show-versions: buildlocal
+	@echo "### rpn version:"
+	@./rpn -v
+
+	@echo
+	@echo "### go module versions:"
+	@go list -m all
+
+	@echo
+	@echo "### go version used for building:"
+	@grep -m 1 go go.mod

README.md

@@ -1,4 +1,8 @@
-## Reverse Polish Notation Calculator for the commandline
+## Programmable command-line calculator using reverse polish notation
+
+[![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) 
 
 This is a small commandline calculator which takes its input in
 [reverse polish notation](https://en.wikipedia.org/wiki/Reverse_Polish_notation)
@@ -65,6 +69,8 @@ DEBUG(012):      push to stack: 200.00
 = 200
 ```
 
+For a very good explanation how reverse polish notation and the stack works [watch this video by Prof. Brailsford](https://youtu.be/7ha78yWRDlE?si=9MCp59jAAG8fXavP)
+
 ## Usage
 
 Basically   you  enter   numbers  followed   by  an   operator  or   a

calc.go

@@ -20,7 +20,6 @@ package main
 import (
 	"errors"
 	"fmt"
-	"math"
 	"os"
 	"regexp"
 	"strconv"
@@ -52,6 +51,8 @@ debug                toggle debug output
 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
 history              display calculation history
 help|?               show this message
 quit|exit|c-d|c-c    exit program
@@ -80,7 +81,7 @@ median               median of all values`
 // 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`
+	Commands  string = `dump reverse debug undebug clear batch shift undo help history manual exit quit swap`
 	Constants string = `Pi Phi Sqrt2 SqrtE SqrtPi SqrtPhi Ln2 Log2E Ln10 Log10E`
 )
 
@@ -192,20 +193,6 @@ func (c *Calc) Eval(line string) {
 			c.stack.Backup()
 			c.stack.Push(num)
 		} else {
-			/*
-				if contains(c.MathFunctions, item) {
-					// go builtin math function, if implemented
-					c.mathfunc(item)
-					continue
-				}
-
-				if contains(c.BatchFunctions, item) {
-					// math functions only supported in batch mode like max or mean
-					c.batchfunc(item)
-					continue
-				}
-			*/
-
 			if contains(c.Constants, item) {
 				// put the constant onto the stack
 				c.stack.Backup()
@@ -271,6 +258,13 @@ func (c *Calc) Eval(line string) {
 			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":
@@ -376,50 +370,6 @@ func (c *Calc) Debug(msg string) {
 	}
 }
 
-// do simple calculations
-func (c *Calc) simple(op byte) {
-	c.stack.Backup()
-
-	for c.stack.Len() > 1 {
-		b := c.stack.Pop()
-		a := c.stack.Pop()
-		var x float64
-
-		c.Debug(fmt.Sprintf("evaluating: %.2f %c %.2f", a, op, b))
-
-		switch op {
-		case '+':
-			x = a + b
-		case '-':
-			x = a - b
-		case 'x':
-			fallthrough // alias for *
-		case '*':
-			x = a * b
-		case '/':
-			if b == 0 {
-				fmt.Println("error: division by null!")
-				return
-			}
-			x = a / b
-		case '^':
-			x = math.Pow(a, b)
-		default:
-			panic("invalid operator!")
-		}
-
-		c.stack.Push(x)
-
-		c.History("%f %c %f = %f", a, op, b, x)
-
-		if !c.batch {
-			break
-		}
-	}
-
-	c.Result()
-}
-
 func (c *Calc) luafunc(funcname string) {
 	// called from calc loop
 	var x float64

calc_test.go

@@ -0,0 +1,141 @@
+/*
+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 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)
+			}
+		})
+	}
+}

main.go

@@ -30,7 +30,7 @@ import (
 	lua "github.com/yuin/gopher-lua"
 )
 
-const VERSION string = "2.0.1"
+const VERSION string = "2.0.2"
 
 const Usage string = `This is rpn, a reverse polish notation calculator cli.
 

rpn.go

@@ -222,17 +222,3 @@ AUTHORS
     Thomas von Dein tom AT vondein DOT org
 
 `
-var usage = `
-
-Usage: rpn [-bdvh] [<operator>]
-
-Options:
-  -b, --batchmode   enable batch mode
-  -d, --debug       enable debug mode
-  -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 +
-
-`

rpn.pod

@@ -116,7 +116,9 @@ You can use B<dump> to display the stack. If debugging
 is enabled (C<-d> switch or B<debug> toggle command), then the backup
 stack is also being displayed.
 
-The stack can be reversed using the B<reverse> command.
+The  stack can  be  reversed using  the  B<reverse> command.  However,
+sometimes only  the last two  values are in  the wrong order.  Use the
+B<swap> command to exchange them.
 
 You can use the B<shift> command to remove the last number from the
 stack.

stack.go

@@ -115,6 +115,26 @@ func (s *Stack) Shift(num ...int) {
 	}
 }
 
+func (s *Stack) Swap() {
+	s.mutex.Lock()
+	defer s.mutex.Unlock()
+
+	if s.linklist.Len() < 2 {
+		return
+	}
+
+	a := s.linklist.Back()
+	s.linklist.Remove(a)
+
+	b := s.linklist.Back()
+	s.linklist.Remove(b)
+
+	s.Debug(fmt.Sprintf("swapping %.2f with %.2f", b.Value, a.Value))
+
+	s.linklist.PushBack(a.Value)
+	s.linklist.PushBack(b.Value)
+}
+
 // Return the last num items from the stack w/o modifying it.
 func (s *Stack) Last(num ...int) []float64 {
 	items := []float64{}

stack_test.go

@@ -0,0 +1,190 @@
+/*
+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 (
+	"testing"
+)
+
+func TestPush(t *testing.T) {
+	t.Run("push", func(t *testing.T) {
+		s := NewStack()
+		s.Push(5)
+
+		if s.linklist.Back().Value != 5.0 {
+			t.Errorf("push failed:\n+++  got: %f\n--- want: %f",
+				s.linklist.Back().Value, 5.0)
+		}
+	})
+}
+
+func TestPop(t *testing.T) {
+	t.Run("pop", func(t *testing.T) {
+		s := NewStack()
+		s.Push(5)
+		got := s.Pop()
+
+		if got != 5.0 {
+			t.Errorf("pop failed:\n+++  got: %f\n--- want: %f",
+				got, 5.0)
+		}
+
+		if s.Len() != 0 {
+			t.Errorf("stack not empty after pop()")
+		}
+	})
+}
+
+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()
+
+		if s.Len() != 2 {
+			t.Errorf("stack len not correct after pop:\n+++  got: %d\n--- want: %d",
+				s.Len(), 2)
+		}
+	})
+}
+
+func TestShift(t *testing.T) {
+	t.Run("shift", func(t *testing.T) {
+		s := NewStack()
+		s.Shift()
+
+		if s.Len() != 0 {
+			t.Errorf("stack not empty after shift()")
+		}
+	})
+}
+
+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()
+
+		if s.Len() != 0 {
+			t.Errorf("stack not empty after clear()")
+		}
+	})
+}
+
+func TestLast(t *testing.T) {
+	t.Run("last", func(t *testing.T) {
+		s := NewStack()
+		s.Push(5)
+		got := s.Last()
+
+		if len(got) != 1 {
+			t.Errorf("last failed:\n+++  got: %d elements\n--- want: %d elements",
+				len(got), 1)
+		}
+
+		if got[0] != 5.0 {
+			t.Errorf("last failed:\n+++  got: %f\n--- want: %f",
+				got, 5.0)
+		}
+
+		if s.Len() != 1 {
+			t.Errorf("stack modified after last()")
+		}
+	})
+}
+
+func TestAll(t *testing.T) {
+	t.Run("all", func(t *testing.T) {
+		s := NewStack()
+		list := []float64{2, 4, 6, 8}
+
+		for _, item := range list {
+			s.Push(item)
+		}
+
+		got := s.All()
+
+		if len(got) != len(list) {
+			t.Errorf("all failed:\n+++  got: %d elements\n--- want: %d elements",
+				len(got), len(list))
+		}
+
+		for i := 1; i < len(list); i++ {
+			if got[i] != list[i] {
+				t.Errorf("all failed (element %d):\n+++  got: %f\n--- want: %f",
+					i, got[i], list[i])
+			}
+		}
+
+		if s.Len() != len(list) {
+			t.Errorf("stack modified after last()")
+		}
+	})
+}
+
+func TestBackupRestore(t *testing.T) {
+	t.Run("shift", func(t *testing.T) {
+		s := NewStack()
+		s.Push(5)
+		s.Backup()
+		s.Clear()
+		s.Restore()
+
+		if s.Len() != 1 {
+			t.Errorf("stack not correctly restored()")
+		}
+
+		a := s.Pop()
+		if a != 5.0 {
+			t.Errorf("stack not identical to old revision:\n+++  got: %f\n--- want: %f",
+				a, 5.0)
+		}
+	})
+}
+
+func TestReverse(t *testing.T) {
+	t.Run("reverse", func(t *testing.T) {
+		s := NewStack()
+		list := []float64{2, 4, 6}
+		reverse := []float64{6, 4, 2}
+
+		for _, item := range list {
+			s.Push(item)
+		}
+
+		s.Reverse()
+
+		got := s.All()
+
+		if len(got) != len(list) {
+			t.Errorf("all failed:\n+++  got: %d elements\n--- want: %d elements",
+				len(got), len(list))
+		}
+
+		for i := 1; i < len(reverse); i++ {
+			if got[i] != reverse[i] {
+				t.Errorf("reverse failed (element %d):\n+++  got: %f\n--- want: %f",
+					i, got[i], list[i])
+			}
+		}
+	})
+}

util_test.go

@@ -0,0 +1,32 @@
+/*
+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 (
+	"testing"
+)
+
+func TestContains(t *testing.T) {
+	list := []string{"a", "b", "c"}
+
+	t.Run("contains", func(t *testing.T) {
+		if !contains(list, "a") {
+			t.Errorf("a in [a,b,c] not found")
+		}
+	})
+}