refactored dir layout

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)
+	}
+}