return statement

example/hello_world.hyc

@@ -1,4 +1,5 @@
 func join :: (a, b) = {
     let result :: String = from(a, b);
+    return result;
 };
 let foo :: String = join("f", "oo");

src/front/lex.rs

@@ -94,6 +94,7 @@ fn lex_reserved_identifier(input: &Bytes) -> IResult<&Bytes, Token> {
                 "else" => Token::Else,
                 "let" => Token::Let,
                 "func" => Token::Func,
+                "return" => Token::Return,
                 "true" => Token::Bool(true),
                 "false" => Token::Bool(false),
                 _ => Token::Identifier(syntax.to_string()),

src/front/model.rs

@@ -18,7 +18,7 @@ pub enum Token {
     LBrace, RBrace,
     Semicolon, Colon, Comma,
 
-    If, Else, Let, Func,
+    If, Else, Let, Func, Return,
 }
 
 /// Token struct with position information.
@@ -103,6 +103,7 @@ pub enum Stmt {
     Let(Ident, Ident, Expr),
     Func(Ident, Vec<Ident>, Vec<Stmt>),
     Call(Ident, Vec<Expr>),
+    Return(Expr),
 }
 
 #[derive(Clone, Debug, PartialEq)]

src/front/parser.rs

@@ -21,6 +21,8 @@ macro_rules! tag_token (
 
 tag_token!(tag_let, Token::Let);
 tag_token!(tag_func, Token::Func);
+tag_token!(tag_return, Token::Return);
+
 tag_token!(tag_assign, Token::Assign);
 tag_token!(tag_typehint, Token::Typehint);
 tag_token!(tag_semicolon, Token::Semicolon);
@@ -148,6 +150,17 @@ fn parse_expr_lowest(input: Tokens) -> IResult<Tokens, Expr> {
     parse_expr_with(input, Precedence::Lowest)
 }
 
+fn parse_return_stmt(input: Tokens) -> IResult<Tokens, Stmt> {
+    map(
+        delimited(
+            tag_return,
+            parse_expr_lowest,
+            tag_semicolon,
+        ),
+        Stmt::Return,
+    )(input)
+}
+
 fn parse_call_stmt(input: Tokens) -> IResult<Tokens, Stmt> {
     map(
         tuple((
@@ -202,6 +215,7 @@ fn parse_stmt(input: Tokens) -> IResult<Tokens, Stmt> {
         parse_let_stmt,
         parse_func_stmt,
         parse_call_stmt,
+        parse_return_stmt,
     ))(input)
 }