implement command line completion of command names

Author: itchyny

README.md

@@ -53,7 +53,7 @@ This binary editor is influenced by the Vim editor.
   - `:quit`, `ZQ`, `:qall`, `:write`,
     `:wq`, `ZZ`, `:xit`, `:xall`, `:cquit`
 - Window operations
-  - `:wincmd [nolhkjtbpKJHL]`, `<C-w>[nolhkjtbpKJHL]`
+  - `:wincmd [nohjkltbpHJKL]`, `<C-w>[nohjkltbpHJKL]`
 - Cursor motions
   - `h`, `j`, `k`, `l`, `w`, `b`, `^`, `0`, `$`,
     `<C-[fb]>`, `<C-[du]>`, `<C-[ey]>`, `<C-[np]>`,

cmdline/cmdline.go

@@ -205,7 +205,7 @@ func (c *Cmdline) execute() (finish bool) {
 	defer c.saveHistory()
 	switch c.typ {
 	case ':':
-		cmd, r, bang, _, arg, err := parse(string(c.cmdline))
+		cmd, r, bang, _, _, arg, err := parse(string(c.cmdline))
 		if err != nil {
 			c.eventCh <- event.Event{Type: event.Error, Error: err}
 		} else if cmd.name != "" {

cmdline/command.go

@@ -4,33 +4,54 @@ import "github.com/itchyny/bed/event"
 
 type command struct {
 	name      string
+	fullname  string
 	eventType event.Type
+	rangeType rangeType
+}
+
+type rangeType int
+
+const (
+	rangeNone rangeType = 1 << iota
+	rangeCount
+	rangeBoth
+)
+
+func (rt rangeType) allows(r *event.Range) bool {
+	switch {
+	case r == nil:
+		return rt&rangeNone != 0
+	case r.To == nil:
+		return rt&rangeCount != 0
+	default:
+		return rt&rangeBoth != 0
+	}
 }
 
 var commands = []command{
-	{"e[dit]", event.Edit},
-	{"ene[w]", event.Enew},
-	{"new", event.New},
-	{"vne[w]", event.Vnew},
-	{"on[ly]", event.Only},
-	{"winc[md]", event.Wincmd},
-
-	{"go[to]", event.CursorGoto},
-	{"%", event.CursorGoto},
-
-	{"u[ndo]", event.Undo},
-	{"red[o]", event.Redo},
-
-	{"pw[d]", event.Pwd},
-	{"cd", event.Chdir},
-	{"chd[ir]", event.Chdir},
-	{"exi[t]", event.Quit},
-	{"q[uit]", event.Quit},
-	{"qa[ll]", event.QuitAll},
-	{"quita[ll]", event.QuitAll},
-	{"cq[uit]", event.QuitErr},
-	{"w[rite]", event.Write},
-	{"wq", event.WriteQuit},
-	{"x[it]", event.WriteQuit},
-	{"xa[ll]", event.WriteQuit},
+	{"e[dit]", "edit", event.Edit, rangeNone},
+	{"ene[w]", "enew", event.Enew, rangeNone},
+	{"new", "new", event.New, rangeNone},
+	{"vne[w]", "vnew", event.Vnew, rangeNone},
+	{"on[ly]", "only", event.Only, rangeNone},
+	{"winc[md]", "wincmd", event.Wincmd, rangeNone},
+
+	{"go[to]", "goto", event.CursorGoto, rangeCount},
+	{"%", "%", event.CursorGoto, rangeCount},
+
+	{"u[ndo]", "undo", event.Undo, rangeNone},
+	{"red[o]", "redo", event.Redo, rangeNone},
+
+	{"pw[d]", "pwd", event.Pwd, rangeNone},
+	{"cd", "cd", event.Chdir, rangeNone},
+	{"chd[ir]", "chdir", event.Chdir, rangeNone},
+	{"exi[t]", "exit", event.Quit, rangeNone},
+	{"q[uit]", "quit", event.Quit, rangeNone},
+	{"qa[ll]", "qall", event.QuitAll, rangeNone},
+	{"quita[ll]", "quitall", event.QuitAll, rangeNone},
+	{"cq[uit]", "cquit", event.QuitErr, rangeNone},
+	{"w[rite]", "write", event.Write, rangeNone | rangeBoth},
+	{"wq", "wq", event.WriteQuit, rangeNone | rangeBoth},
+	{"x[it]", "xit", event.WriteQuit, rangeNone | rangeBoth},
+	{"xa[ll]", "xall", event.WriteQuit, rangeNone | rangeBoth},
 }

cmdline/completor.go

@@ -5,13 +5,16 @@ import (
 	"path/filepath"
 	"slices"
 	"strings"
+	"unicode"
+	"unicode/utf8"
 
 	"github.com/itchyny/bed/event"
 )
 
 type completor struct {
 	fs      fs
 	env     env
+	command bool
 	target  string
 	arg     string
 	results []string
@@ -22,24 +25,24 @@ func newCompletor(fs fs, env env) *completor {
 	return &completor{fs: fs, env: env}
 }
 
-func (c *completor) clear() {
-	c.target = ""
-	c.arg = ""
-	c.results = nil
-	c.index = 0
-}
-
 func (c *completor) complete(cmdline string, forward bool) string {
-	cmd, _, _, prefix, arg, _ := parse(cmdline)
+	cmd, r, _, name, prefix, arg, _ := parse(cmdline)
+	if name == "" || c.command ||
+		!hasSuffixFunc(prefix, unicode.IsSpace) && cmd.fullname != name {
+		cmdline = c.completeCommand(cmdline, name, prefix, r, forward)
+		if c.results != nil {
+			return cmdline
+		}
+		prefix = cmdline
+	}
 	switch cmd.eventType {
 	case event.Edit, event.New, event.Vnew, event.Write:
-		return c.completeFilepaths(cmdline, prefix, arg, forward, false)
+		return c.completeFilepath(cmdline, prefix, arg, forward, false)
 	case event.Chdir:
-		return c.completeFilepaths(cmdline, prefix, arg, forward, true)
+		return c.completeFilepath(cmdline, prefix, arg, forward, true)
 	case event.Wincmd:
 		return c.completeWincmd(cmdline, prefix, arg, forward)
 	default:
-		c.clear()
 		return cmdline
 	}
 }
@@ -53,35 +56,45 @@ func (c *completor) completeNext(prefix string, forward bool) string {
 	if c.index < 0 {
 		return c.target
 	}
+	if len(c.results) == 1 {
+		defer c.clear()
+	}
 	return prefix + c.arg + c.results[c.index]
 }
 
-func (c *completor) completeFilepaths(
-	cmdline, prefix, arg string, forward, dirOnly bool,
+func (c *completor) completeCommand(
+	cmdline, name, prefix string, r *event.Range, forward bool,
 ) string {
-	if !strings.HasSuffix(prefix, " ") {
-		prefix += " "
+	prefix = prefix[:len(prefix)-len(name)]
+	if c.results == nil {
+		c.command, c.target, c.index = true, cmdline, -1
+		c.arg, c.results = "", c.listCommandNames(name, r)
 	}
-	if len(c.results) > 0 {
-		return c.completeNext(prefix, forward)
+	return c.completeNext(prefix, forward)
+}
+
+func (*completor) listCommandNames(name string, r *event.Range) []string {
+	var targets []string
+	for _, cmd := range commands {
+		if strings.HasPrefix(cmd.fullname, name) && cmd.rangeType.allows(r) {
+			targets = append(targets, cmd.fullname)
+		}
 	}
-	c.target = cmdline
-	c.index = 0
-	c.arg, c.results = c.listFileNames(arg, dirOnly)
-	if len(c.results) == 1 {
-		cmdline := prefix + c.arg + c.results[0]
-		c.results = nil
-		return cmdline
+	slices.Sort(targets)
+	return targets
+}
+
+func (c *completor) completeFilepath(
+	cmdline, prefix, arg string, forward, dirOnly bool,
+) string {
+	if !hasSuffixFunc(prefix, unicode.IsSpace) {
+		prefix += " "
 	}
-	if len(c.results) > 1 {
-		if forward {
-			c.index = 0
-			return prefix + c.arg + c.results[0]
-		}
-		c.index = len(c.results) - 1
-		return prefix + c.arg + c.results[len(c.results)-1]
+	if c.results == nil {
+		c.command, c.target, c.index = false, cmdline, -1
+		c.arg, c.results = c.listFileNames(arg, dirOnly)
 	}
-	return cmdline
+	return c.completeNext(prefix, forward)
 }
 
 const separator = string(filepath.Separator)
@@ -224,17 +237,25 @@ func (c *completor) expandPath(path string) (string, func(string) string) {
 }
 
 func (c *completor) completeWincmd(cmdline, prefix, arg string, forward bool) string {
-	if !strings.HasSuffix(prefix, " ") {
+	if !hasSuffixFunc(prefix, unicode.IsSpace) {
 		prefix += " "
 	}
-	if len(c.results) > 0 {
-		return c.completeNext(prefix, forward)
-	}
-	if len(arg) > 0 {
-		return cmdline
+	if c.results == nil {
+		if len(arg) > 0 {
+			return cmdline
+		}
+		c.command, c.target, c.arg, c.index = false, cmdline, "", -1
+		c.results = strings.Split("nohjkltbpHJKL", "")
 	}
-	c.target = cmdline
-	c.results = []string{"n", "h", "l", "k", "j", "H", "L", "K", "J", "t", "b", "p"}
-	c.index = -1
-	return cmdline
+	return c.completeNext(prefix, forward)
+}
+
+func (c *completor) clear() {
+	c.command, c.target, c.arg = false, "", ""
+	c.results, c.index = nil, 0
+}
+
+func hasSuffixFunc(s string, f func(rune) bool) bool {
+	r, _ := utf8.DecodeLastRuneInString(s)
+	return f(r)
 }