use generics for contains() and add generic exists()

fix pod formatting (fixes #24)

calc.go

@@ -62,6 +62,8 @@ 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
@@ -119,20 +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
 	}
@@ -235,6 +245,15 @@ func (c *Calc) Eval(line string) {
 			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()
@@ -242,7 +261,7 @@ func (c *Calc) Eval(line string) {
 				continue
 			}
 
-			if _, ok := c.Funcalls[item]; ok {
+			if exists(c.Funcalls, item) {
 				if err := c.DoFuncall(item); err != nil {
 					fmt.Println(err)
 				} else {
@@ -251,8 +270,12 @@ func (c *Calc) Eval(line string) {
 				continue
 			}
 
-			if c.batch {
+			if exists(c.BatchFuncalls, item) {
-				if _, ok := c.BatchFuncalls[item]; ok {
+				if !c.batch {
+					fmt.Println("only supported in batch mode")
+					continue
+				}
+
 				if err := c.DoFuncall(item); err != nil {
 					fmt.Println(err)
 				} else {
@@ -260,12 +283,6 @@ func (c *Calc) Eval(line string) {
 				}
 				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
@@ -285,22 +302,22 @@ func (c *Calc) Eval(line string) {
 			}
 
 			// internal commands
-			if _, ok := c.Commands[item]; ok {
+			if exists(c.Commands, item) {
 				c.Commands[item].Func(c)
 				continue
 			}
 
-			if _, ok := c.ShowCommands[item]; ok {
+			if exists(c.ShowCommands, item) {
 				c.ShowCommands[item].Func(c)
 				continue
 			}
 
-			if _, ok := c.StackCommands[item]; ok {
+			if exists(c.StackCommands, item) {
 				c.StackCommands[item].Func(c)
 				continue
 			}
 
-			if _, ok := c.SettingsCommands[item]; ok {
+			if exists(c.SettingsCommands, item) {
 				c.SettingsCommands[item].Func(c)
 				continue
 			}
@@ -488,7 +505,7 @@ 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])

calc_test.go

@@ -241,6 +241,45 @@ func TestCalc(t *testing.T) {
 			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 _, tt := range tests {

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)
@@ -117,6 +121,15 @@ func (c *Calc) SetCommands() {
 				}
 			},
 		),
+
+		"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]))
+				}
+			},
+		),
 	}
 
 	c.StackCommands = Commands{
@@ -175,6 +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
@@ -196,6 +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

@@ -387,6 +387,85 @@ func DefineFunctions() Funcalls {
 				return NewR(math.Hypot(arg[0], arg[1]), nil)
 			},
 			2),
+
+		// converters of all kinds
+		"cm-to-inch": NewFuncall(
+			func(arg Numbers) R {
+				return NewR(arg[0]/2.54, nil)
+			},
+			1),
+
+		"inch-to-cm": NewFuncall(
+			func(arg Numbers) R {
+				return NewR(arg[0]*2.54, nil)
+			},
+			1),
+
+		"gallons-to-liters": NewFuncall(
+			func(arg Numbers) R {
+				return NewR(arg[0]*3.785, nil)
+			},
+			1),
+
+		"liters-to-gallons": NewFuncall(
+			func(arg Numbers) R {
+				return NewR(arg[0]/3.785, nil)
+			},
+			1),
+
+		"yards-to-meters": NewFuncall(
+			func(arg Numbers) R {
+				return NewR(arg[0]*91.44, nil)
+			},
+			1),
+
+		"meters-to-yards": NewFuncall(
+			func(arg Numbers) R {
+				return NewR(arg[0]/91.44, nil)
+			},
+			1),
+
+		"miles-to-kilometers": NewFuncall(
+			func(arg Numbers) R {
+				return NewR(arg[0]*1.609, nil)
+			},
+			1),
+
+		"kilometers-to-miles": NewFuncall(
+			func(arg Numbers) R {
+				return NewR(arg[0]/1.609, nil)
+			},
+			1),
+
+		"or": NewFuncall(
+			func(arg Numbers) R {
+				return NewR(float64(int(arg[0])|int(arg[1])), nil)
+			},
+			2),
+
+		"and": NewFuncall(
+			func(arg Numbers) R {
+				return NewR(float64(int(arg[0])&int(arg[1])), nil)
+			},
+			2),
+
+		"xor": NewFuncall(
+			func(arg Numbers) R {
+				return NewR(float64(int(arg[0])^int(arg[1])), nil)
+			},
+			2),
+
+		"<": NewFuncall(
+			func(arg Numbers) R {
+				return NewR(float64(int(arg[0])<<int(arg[1])), nil)
+			},
+			2),
+
+		">": NewFuncall(
+			func(arg Numbers) R {
+				return NewR(float64(int(arg[0])>>int(arg[1])), nil)
+			},
+			2),
 	}
 
 	// aliases

main.go

@@ -30,7 +30,7 @@ import (
 	lua "github.com/yuin/gopher-lua"
 )
 
-const VERSION string = "2.0.9"
+const VERSION string = "2.0.11"
 
 const Usage string = `This is rpn, a reverse polish notation calculator cli.
 

rpn.go

@@ -105,6 +105,9 @@ 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).
+
   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
@@ -129,6 +132,14 @@ DESCRIPTION
         x                    multiply (alias: *)
         ^                    power
 
+    Bitwise operators:
+
+        and                  bitwise and
+        or                   bitwise or
+        xor                  bitwise xor
+        <                    left shift
+        >                    right shift
+
     Percent functions:
 
         %                    percent
@@ -150,19 +161,44 @@ DESCRIPTION
         log10 log1p log2 logb pow round roundtoeven sin sinh tan tanh trunc y0
         y1 copysign dim hypot
 
-    Commands:
+    Conversion functions:
+
+        cm-to-inch
+        inch-to-cm
+        gallons-to-liters
+        liters-to-gallons
+        yards-to-meters
+        meters-to-yards
+        miles-to-kilometers
+        kilometers-to-miles
+
+    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:
+
         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
-        history              display calculation history
+        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:
@@ -172,6 +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

@@ -109,6 +109,9 @@ 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).
+
 =head2 STACK MANIPULATION
 
 There are lots of stack manipulation commands provided. The most
@@ -136,6 +139,14 @@ Basic operators:
     x                    multiply (alias: *)
     ^                    power
 
+Bitwise operators:
+
+    and                  bitwise and
+    or                   bitwise or
+    xor                  bitwise xor
+    <                    left shift
+    >                    right shift
+
 Percent functions:
 
     %                    percent
@@ -157,19 +168,44 @@ 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
+    inch-to-cm
+    gallons-to-liters
+    liters-to-gallons
+    yards-to-meters
+    meters-to-yards
+    miles-to-kilometers
+    kilometers-to-miles
+
+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:
+
     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
-    history              display calculation history
+    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
 
 
@@ -180,6 +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

util.go

@@ -23,16 +23,24 @@ import (
 	"strings"
 )
 
-// find an item in a list
+// find an item in a list, generic variant
-func contains(s []string, e string) bool {
+func contains[E comparable](s []E, v E) bool {
-	for _, a := range s {
+	for _, vs := range s {
-		if a == e {
+		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":