More sensible parsing of command leaders.

parse/parse.go

@@ -181,14 +181,14 @@ func (fn *Form) parse(ps *parser) {
 		parseSpaces(fn, ps)
 	}
 	leader, starter := findLeader(ps)
-	if leader != "" {
+	if leader != "" && starter {
 		// Parse Control.
-		if starter {
-			fn.setControl(parseControl(ps, leader))
-		} else {
+		fn.setControl(parseControl(ps, leader))
+		parseSpaces(fn, ps)
+	} else {
+		if leader != "" {
 			ps.error(fmt.Errorf("bogus command leader %q ignored", leader))
 		}
-	} else {
 		// Parse head.
 		if len(fn.Assignments) > 0 && !startsCompound(ps.peek()) {
 			// Assignment-only form.

parse/parser.go

@@ -42,9 +42,9 @@ func (ps *parser) hasPrefix(prefix string) bool {
 	return strings.HasPrefix(ps.src[ps.pos:], prefix)
 }
 
-// findWord look aheads a series of runes in [a-z] followed by ' ', '\t' or
-// '\n'. If the lookahead fails, it returns an empty string. It is useful for
-// looking for command leaders.
+// findWord looks ahead for [a-z]* that is also a valid compound. If the
+// lookahead fails, it returns an empty string. It is useful for looking for
+// command leaders.
 func (ps *parser) findPossibleLeader() string {
 	rest := ps.src[ps.pos:]
 	i := strings.IndexFunc(rest, func(r rune) bool {
@@ -54,12 +54,11 @@ func (ps *parser) findPossibleLeader() string {
 		// The whole rest is just one possible leader.
 		return rest
 	}
-	switch rest[i] {
-	case ' ', '\t', '\n':
-		return rest[:i]
-	default:
+	r, _ := utf8.DecodeRuneInString(rest[i:])
+	if startsPrimary(r) {
 		return ""
 	}
+	return rest[:i]
 }
 
 func (ps *parser) next() rune {