added fuzzy testing

* added commandline and stdin tests using testscript

---------

Co-authored-by: Thomas von Dein <tom@vondein.org>

Makefile

@@ -51,14 +51,17 @@ 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)
 
 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

calc.go

@@ -121,20 +121,28 @@ func (c *Calc) GetCompleteCustomFuncalls() func(string) []string {
 		}
 
 		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
 	}
@@ -214,12 +222,12 @@ func (c *Calc) Prompt() string {
 }
 
 // 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)
@@ -231,100 +239,8 @@ 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 {
-			// try hex
-			var i int
-			_, err := fmt.Sscanf(item, "0x%x", &i)
-			if err == nil {
-				c.stack.Backup()
-				c.stack.Push(float64(i))
-				continue
-			}
-
-			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.EvalLuaFunction(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
-			}
-
-			// internal commands
-			if _, ok := c.Commands[item]; ok {
-				c.Commands[item].Func(c)
-				continue
-			}
-
-			if _, ok := c.ShowCommands[item]; ok {
-				c.ShowCommands[item].Func(c)
-				continue
-			}
-
-			if _, ok := c.StackCommands[item]; ok {
-				c.StackCommands[item].Func(c)
-				continue
-			}
-
-			if _, ok := c.SettingsCommands[item]; ok {
-				c.SettingsCommands[item].Func(c)
-				continue
-			}
-
-			switch item {
-			case "?":
-				fallthrough
-			case "help":
-				c.PrintHelp()
-
-			default:
-				fmt.Println("unknown command or operator!")
-			}
+		if err := c.EvalItem(item); err != nil {
+			return err
 		}
 	}
 
@@ -337,6 +253,106 @@ func (c *Calc) Eval(line string) {
 		last := c.stack.Last(5)
 		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)
+	} else {
+		// 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())
+			} else {
+				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())
+			} else {
+				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 "?":
+			fallthrough
+		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
@@ -349,7 +365,7 @@ 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
@@ -499,7 +515,7 @@ 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])
@@ -512,8 +528,10 @@ 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)
 

calc_test.go

@@ -19,6 +19,8 @@ package main
 
 import (
 	"fmt"
+	"strconv"
+	"strings"
 	"testing"
 
 	lua "github.com/yuin/gopher-lua"
@@ -75,7 +77,9 @@ func TestCommentsAndWhitespace(t *testing.T) {
 
 		t.Run(testname, func(t *testing.T) {
 			for _, line := range tt.cmd {
-				calc.Eval(line)
+				if err := calc.Eval(line); err != nil {
+					t.Errorf(err.Error())
+				}
 			}
 			got := calc.stack.Last()
 
@@ -288,7 +292,9 @@ func TestCalc(t *testing.T) {
 
 		t.Run(testname, func(t *testing.T) {
 			calc.batch = tt.batch
-			calc.Eval(tt.cmd)
+			if err := calc.Eval(tt.cmd); err != nil {
+				t.Errorf(err.Error())
+			}
 			got := calc.Result()
 			calc.stack.Clear()
 			if got != tt.exp {
@@ -350,3 +356,60 @@ func TestCalcLua(t *testing.T) {
 		})
 	}
 }
+
+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",
+	}
+
+	for _, item := range legal {
+		f.Add(item)
+	}
+
+	calc := NewCalc()
+	var i int
+
+	f.Fuzz(func(t *testing.T, line string) {
+		t.Logf("Stack:\n%v\n", calc.stack.All())
+		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", &i)
+				// 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 {
+							t.Errorf("Fuzzy input accepted: <%s>", line)
+						}
+					}
+				}
+			}
+		}
+	})
+}

command.go

@@ -18,8 +18,12 @@ along with this program. If not, see <http://www.gnu.org/licenses/>.
 package main
 
 import (
+	"bufio"
 	"fmt"
 	"os"
+	"os/exec"
+	"strconv"
+	"strings"
 )
 
 type CommandFunction func(*Calc)
@@ -184,6 +188,102 @@ func (c *Calc) SetCommands() {
 				}
 			},
 		),
+
+		"edit": NewCommand(
+			"edit the stack interactively",
+			func(c *Calc) {
+				if c.stack.Len() == 0 {
+					fmt.Println("empty stack")
+					return
+				}
+
+				c.stack.Backup()
+
+				// put the stack contents into a tmp file
+				tmp, err := os.CreateTemp("", "stack")
+				if err != nil {
+					fmt.Println(err)
+					return
+				}
+				defer os.Remove(tmp.Name())
+
+				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 c.stack.All() {
+					_, err = fmt.Fprintf(tmp, "%f\n", item)
+					if err != nil {
+						fmt.Println(err)
+						return
+					}
+				}
+
+				tmp.Close()
+
+				// 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 modified.Close()
+
+				// reset the stack
+				c.stack.Clear()
+
+				// and put the new contents (if legit) back onto the stack
+				scanner := bufio.NewScanner(modified)
+				for scanner.Scan() {
+					line := strings.TrimSpace(c.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
+					}
+
+					c.stack.Push(num)
+				}
+
+				if err := scanner.Err(); err != nil {
+					fmt.Println("Error reading from file:", err)
+				}
+			},
+		),
 	}
 
 	// general commands
@@ -205,6 +305,15 @@ func (c *Calc) SetCommands() {
 
 	// aliases
 	c.Commands["quit"] = c.Commands["exit"]
-	c.SettingsCommands["undebug"] = c.SettingsCommands["nodebug"]
-	c.SettingsCommands["show"] = c.SettingsCommands["showstack"]
+
+	c.SettingsCommands["d"] = c.SettingsCommands["debug"]
+	c.SettingsCommands["b"] = c.SettingsCommands["batch"]
+	c.SettingsCommands["s"] = 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"]
 }

funcs.go

@@ -457,12 +457,20 @@ func DefineFunctions() Funcalls {
 
 		"<": NewFuncall(
 			func(arg Numbers) R {
+				// Shift by negative number provibited, so check it.
+				// Note that we check agains uint64 overflow as well here
+				if arg[1] < 0 || uint64(arg[1]) > math.MaxInt64 {
+					return NewR(0, errors.New("negative shift amount"))
+				}
 				return NewR(float64(int(arg[0])<<int(arg[1])), nil)
 			},
 			2),
 
 		">": NewFuncall(
 			func(arg Numbers) R {
+				if arg[1] < 0 || uint64(arg[1]) > math.MaxInt64 {
+					return NewR(0, errors.New("negative shift amount"))
+				}
 				return NewR(float64(int(arg[0])>>int(arg[1])), nil)
 			},
 			2),

go.mod

@@ -4,7 +4,9 @@ go 1.20
 
 require (
 	github.com/chzyer/readline v1.5.1 // indirect
+	github.com/rogpeppe/go-internal v1.11.0 // 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
+	golang.org/x/sys v0.0.0-20220722155257-8c9f86f7a55f // indirect
+	golang.org/x/tools v0.1.12 // indirect
 )

go.sum

@@ -2,9 +2,15 @@ github.com/chzyer/logex v1.2.1/go.mod h1:JLbx6lG2kDbNRFnfkgvh4eRJRPX1QCoOIWomwys
 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/go.mod h1:2JlltgoNkt4TW/z9V/IzDdFaMTM2JPIi26O1pF38GC8=
+github.com/rogpeppe/go-internal v1.11.0 h1:cWPaGQEPrBb5/AsnsZesgZZ9yb1OQ+GOISoDNXVBh4M=
+github.com/rogpeppe/go-internal v1.11.0/go.mod h1:ddIwULY96R17DhadqLgMfk9H9tvdUzkipdSkR5nkCZA=
 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=
 golang.org/x/sys v0.0.0-20220310020820-b874c991c1a5/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
+golang.org/x/sys v0.0.0-20220722155257-8c9f86f7a55f h1:v4INt8xihDGvnrfjMDVXGxw9wrfxYyCjk0KbXjhR55s=
+golang.org/x/sys v0.0.0-20220722155257-8c9f86f7a55f/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
+golang.org/x/tools v0.1.12 h1:VveCTK38A2rkS8ZqFY25HIDFscX5X9OoEhJd3quQmXU=
+golang.org/x/tools v0.1.12/go.mod h1:hNGJHUnrk76NpqgfD5Aqm5Crs+Hm0VOH/i9J2+nxYbc=

main.go

@@ -30,7 +30,7 @@ import (
 	lua "github.com/yuin/gopher-lua"
 )
 
-const VERSION string = "2.0.10"
+const VERSION string = "2.0.13"
 
 const Usage string = `This is rpn, a reverse polish notation calculator cli.
 
@@ -42,6 +42,7 @@ Options:
   -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
   -v, --version       show version
   -h, --help          show help
 
@@ -51,6 +52,10 @@ this only when working with stdin. E.g.: echo "2 3 4 5" | rpn +
 Copyright (c) 2023 T.v.Dein`
 
 func main() {
+	os.Exit(Main())
+}
+
+func Main() int {
 	calc := NewCalc()
 
 	showversion := false
@@ -74,12 +79,12 @@ func main() {
 
 	if showversion {
 		fmt.Printf("This is rpn version %s\n", VERSION)
-		return
+		return 0
 	}
 
 	if showhelp {
 		fmt.Println(Usage)
-		return
+		return 0
 	}
 
 	if enabledebug {
@@ -88,7 +93,7 @@ func main() {
 
 	if showmanual {
 		man()
-		os.Exit(0)
+		return 0
 	}
 
 	// the lua state object is global, instanciate it early
@@ -101,14 +106,25 @@ func main() {
 		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
-		calc.Eval(strings.Join(flag.Args(), " "))
-		return
+		if err := calc.Eval(strings.Join(flag.Args(), " ")); err != nil {
+			fmt.Println(err)
+			return 1
+		}
+
+		return 0
 	}
 
 	// interactive mode, need readline
@@ -141,7 +157,10 @@ func main() {
 			break
 		}
 
-		calc.Eval(line)
+		err = calc.Eval(line)
+		if err != nil {
+			fmt.Println(err)
+		}
 		rl.SetPrompt(calc.Prompt())
 	}
 
@@ -150,10 +169,15 @@ func main() {
 		// echo 1 2 3 4 | rpn +
 		// batch mode enabled automatically
 		calc.batch = true
-		calc.Eval(flag.Args()[0])
+		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

main_test.go

@@ -0,0 +1,20 @@
+package main
+
+import (
+	"os"
+	"testing"
+
+	"github.com/rogpeppe/go-internal/testscript"
+)
+
+func TestMain(m *testing.M) {
+	os.Exit(testscript.RunMain(m, map[string]func() int{
+		"testrpn": Main,
+	}))
+}
+
+func TestRpn(t *testing.T) {
+	testscript.Run(t, testscript.Params{
+		Dir: "t",
+	})
+}

rpn.go

@@ -178,16 +178,27 @@ DESCRIPTION
         [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: 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
+    Show commands:
 
-    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 dup duplicate last stack item undo
-    undo last operation
+        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
 
-    Other commands: help|? show this message manual show manual
+    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
+        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:
@@ -197,6 +208,17 @@ 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"

rpn.pod

@@ -186,20 +186,24 @@ Configuration Commands:
     [no]showstack        show the last 5 items of the stack (noshowtack turns it off)
 
 Show commands:
+
     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
     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
@@ -212,6 +216,17 @@ 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

t/cmdline-command.txtar

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

t/cmdline-invalidcommand.txtar

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

t/cmdline-short-stack.txtar

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

t/cmdlinecalc-debug.txtar

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

t/cmdlinecalc-divzero.txtar

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

t/cmdlinecalc-lua.txtar

@@ -0,0 +1,16 @@
+exec testrpn -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.txtar

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

t/getman.txtar

@@ -0,0 +1,2 @@
+exec testrpn -m
+stdout 'This software is licensed under the GNU GENERAL PUBLIC LICENSE'

t/getusage.txtar

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

t/getversion.txtar

@@ -0,0 +1,2 @@
+exec testrpn -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 testrpn
+[unix] stdout '3\n'

t/stdin-batch.txtar

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

t/stdin-calc.txtar

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

t/stdin-help.txtar

@@ -0,0 +1,6 @@
+stdin input.txt
+exec testrpn
+[unix] stdout 'Available configuration commands'
+
+-- input.txt --
+?

t/stdin-use-vars.txtar

@@ -0,0 +1,13 @@
+stdin input.txt
+exec testrpn
+[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 testrpn -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  

util.go

@@ -23,16 +23,24 @@ 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
+}
+
 func const2num(name string) float64 {
 	switch name {
 	case "Pi":
@@ -63,3 +71,7 @@ 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)
+}