parser/expression.go

@@ -65,8 +65,8 @@ func (this *Parser) parseExpressionRootIdent () (entity.Expression, error) {
 		return this.parseDeclarationCore(pos, name)
 	} else {
 		switch name {
-		case "true", "false": // TODO
-		case "nil":           // TODO
+		case "true", "false": return this.parseLiteralBoolean ()
+		case "nil":           return this.parseLiteralNil()
 		case "if":            // TODO
 		case "loop":          // TODO
 		default:              return this.parseVariable()
@@ -150,3 +150,24 @@ func (this *Parser) parseLiteralString () (*entity.LiteralString, error) {
 		ValueUTF8: this.value(),
 	}, nil
 }
+
+func (this *Parser) parseLiteralBoolean () (*entity.LiteralBoolean, error) {
+	err := this.expectValueDesc("Boolean", lexer.Ident, "true", "false")
+	if err != nil { return nil, err }
+	defer this.next()
+	
+	return &entity.LiteralBoolean {
+		Position: this.pos(),
+		Value:    this.value() == "true",
+	}, nil
+}
+
+func (this *Parser) parseLiteralNil () (*entity.LiteralNil, error) {
+	err := this.expectValueDesc("Boolean", lexer.Ident, "nil")
+	if err != nil { return nil, err }
+	defer this.next()
+	
+	return &entity.LiteralNil {
+		Position: this.pos(),
+	}, nil
+}