parse return statements

Author: 54L1M

ast/ast.go

@@ -50,3 +50,13 @@ func (ls *VarStatement) statementNode() {}
 func (ls *VarStatement) TokenLiteral() string {
 	return ls.Token.Literal
 }
+
+type ReturnStatement struct {
+	Token       token.Token
+	ReturnValue Expression
+}
+
+func (rs *ReturnStatement) statementNode() {}
+func (rs *ReturnStatement) TokenLiteral() string {
+	return rs.Token.Literal
+}

parser/parser.go

@@ -45,6 +45,8 @@ func (p *Parser) parseStatement() ast.Statement {
 	switch p.curToken.Type {
 	case token.VAR:
 		return p.parseVarStatement()
+	case token.RETURN:
+		return p.parseReturnStatement()
 	default:
 		return nil
 
@@ -73,3 +75,17 @@ func (p *Parser) parseVarStatement() *ast.VarStatement {
 
 	return stmt
 }
+
+// parse return statement
+func (p *Parser) parseReturnStatement() *ast.ReturnStatement {
+	stmt := &ast.ReturnStatement{Token: p.curToken}
+
+	p.nextToken()
+
+	//TODO:  We're skipping the expressions until we encounter a semicolon
+
+	for !p.curTokenIs(token.SEMICOLON) {
+		p.nextToken()
+	}
+	return stmt
+}

parser/parser_test.go

@@ -7,7 +7,7 @@ import (
 	"github.com/54L1m/mil-lang/lexer"
 )
 
-func TestLetStatement(t *testing.T) {
+func TestVarStatement(t *testing.T) {
 	input := `
 	var x = 5;
 	var y = 10;
@@ -42,6 +42,37 @@ func TestLetStatement(t *testing.T) {
 	}
 }
 
+func TestReturnStatement(t *testing.T) {
+	input := `
+		return 5;
+		return 10;
+		return 993322;
+	`
+	l := lexer.New(input)
+	p := New(l)
+
+	program := p.ParseProgram()
+	checkParseErrors(t, p)
+
+	if len(program.Statements) != 3 {
+		t.Fatalf("program.Statements does not contain 3 statements. got=%d",
+			len(program.Statements))
+	}
+
+	for _, stmt := range program.Statements {
+		returnStmt, ok := stmt.(*ast.ReturnStatement)
+		if !ok {
+			t.Errorf("stmt not *ast.ReturnStatement. got=%T", stmt)
+			continue
+		}
+		if returnStmt.TokenLiteral() != "return" {
+			t.Errorf("returnStmt.TokenLiteral not 'return', got %q",
+				returnStmt.TokenLiteral())
+		}
+	}
+
+}
+
 func testVarStatement(t *testing.T, s ast.Statement, name string) bool {
 	if s.TokenLiteral() != "var" {
 		t.Errorf("s.TokenLiteral not 'var'. got=%q", s.TokenLiteral())