edit: terminate completion early if current token has no node

edit/attr.go

@@ -1,5 +1,6 @@
 package edit
 
+// Styles for UI.
 var (
 	attrForPrompt            = ""
 	attrForRprompt           = "7"
@@ -11,6 +12,12 @@ var (
 	attrForSelectedFile      = ";7"
 )
 
+// Styles for semantic coloring.
+var (
+	styleForBadCommand  = "31;3"
+	styleForBadVariable = "31;3"
+)
+
 var attrForType = map[TokenType]string{
 	ParserError:  "31;3",
 	Bareword:     "",

edit/completion.go

@@ -59,6 +59,9 @@ func (c *completion) next(cycle bool) {
 func startCompletion(ed *Editor, k Key) *leReturn {
 	token := tokenAtDot(ed)
 	node := token.Node
+	if node == nil {
+		return nil
+	}
 
 	c := &completion{
 		start: node.Begin(),

edit/editor.go

@@ -178,6 +178,11 @@ func (ed *Editor) refresh() error {
 	if ed.mode != modeCompletion {
 		// XXX Ignore error
 		ed.tokens, _ = tokenize(ed.line)
+		for _, t := range ed.tokens {
+			for _, colorist := range colorists {
+				t.MoreStyle += colorist(t.Node, ed.evaler)
+			}
+		}
 	}
 	return ed.writer.refresh(&ed.editorState)
 }