edit: color and complete external command names

edit/attr.go

@@ -43,6 +43,7 @@ var styleForSep = map[byte]string{
 
 // Styles for semantic coloring.
 var (
-	styleForBadCommand  = ";31;3"
+	styleForGoodCommand = ";32"
+	styleForBadCommand  = ";31"
 	styleForBadVariable = ";31;3"
 )

edit/colorists.go

@@ -5,19 +5,34 @@ import (
 	"github.com/elves/elvish/parse"
 )
 
-type colorist func(parse.Node, *eval.Evaler) string
+type colorist func(parse.Node, *Editor) string
 
 var colorists = []colorist{
 	colorFormHead,
 	colorVariable,
 }
 
-func colorFormHead(n parse.Node, ev *eval.Evaler) string {
+func colorFormHead(n parse.Node, ed *Editor) string {
 	// BUG doesn't work when the form head is compound
-	return ""
+	n, head := formHead(n)
+	if n == nil {
+		return ""
+	}
+	if goodFormHead(head, ed) {
+		return styleForGoodCommand
+	}
+	return styleForBadCommand
 }
 
-func colorVariable(n parse.Node, ev *eval.Evaler) string {
+func goodFormHead(head string, ed *Editor) bool {
+	if eval.DontSearch(head) {
+		return eval.IsExecutable(head)
+	} else {
+		return ed.evaler.HasVariable("fn-"+head) || ed.isExternal[head]
+	}
+}
+
+func colorVariable(n parse.Node, ed *Editor) string {
 	pn, ok := n.(*parse.Primary)
 	if !ok {
 		return ""
@@ -25,7 +40,7 @@ func colorVariable(n parse.Node, ev *eval.Evaler) string {
 	if pn.Type != parse.Variable || len(pn.Value) == 0 {
 		return ""
 	}
-	has := ev.HasVariable(pn.Value[1:])
+	has := ed.evaler.HasVariable(pn.Value[1:])
 	if has {
 		return ""
 	}

edit/completers.go

@@ -33,6 +33,13 @@ func complFormHead(n parse.Node, ed *Editor) ([]*candidate, int) {
 				tokenPart{head, false}, tokenPart{s[len(head):], true}))
 		}
 	}
+	// XXX reduplication
+	for s := range ed.isExternal {
+		if strings.HasPrefix(s, head) {
+			cands = append(cands, newCandidate(
+				tokenPart{head, false}, tokenPart{s[len(head):], true}))
+		}
+	}
 	return cands, n.Begin()
 }
 

edit/editor.go

@@ -37,6 +37,7 @@ type editorState struct {
 	completionLines       int
 	navigation            *navigation
 	history               history
+	isExternal            map[string]bool
 }
 
 type history struct {
@@ -180,7 +181,7 @@ func (ed *Editor) refresh() error {
 		ed.tokens, _ = tokenize(ed.line)
 		for i, t := range ed.tokens {
 			for _, colorist := range colorists {
-				ed.tokens[i].MoreStyle += colorist(t.Node, ed.evaler)
+				ed.tokens[i].MoreStyle += colorist(t.Node, ed)
 			}
 		}
 	}
@@ -380,6 +381,8 @@ func (ed *Editor) finishReadLine(lr *LineRead) {
 // other signals.
 func (ed *Editor) ReadLine(prompt, rprompt func() string) (lr LineRead) {
 	ed.editorState = editorState{}
+	go ed.updateIsExternal()
+
 	ed.writer.oldBuf.cells = nil
 	ones := ed.reader.Chan()
 

edit/isexternal.go

@@ -0,0 +1,14 @@
+package edit
+
+func (ed *Editor) updateIsExternal() {
+	names := make(chan string, 32)
+	go func() {
+		ed.evaler.AllExecutables(names)
+		close(names)
+	}()
+	isExternal := make(map[string]bool)
+	for name := range names {
+		isExternal[name] = true
+	}
+	ed.isExternal = isExternal
+}