From b455c661a0712ee4488300ca4a3390aa6ce6d7de Mon Sep 17 00:00:00 2001
From: Natapat Samutpong <natapat.samutpong@gmail.com>
Date: Sat, 12 Feb 2022 15:04:44 +0700
Subject: [PATCH] feat: funcs ast

---
 example/hello_world.hyc |  7 +++++--
 src/front/lex.rs        |  6 +++++-
 src/front/model.rs      |  4 +++-
 src/front/parser.rs     | 43 ++++++++++++++++++++++++++++++++++++++---
 src/main.rs             | 11 +++++++++--
 5 files changed, 62 insertions(+), 9 deletions(-)

diff --git a/example/hello_world.hyc b/example/hello_world.hyc
index 98e246c..870e631 100644
--- a/example/hello_world.hyc
+++ b/example/hello_world.hyc
@@ -1,2 +1,5 @@
-let foo :: String = "Hello, ";
-let bar :: String = "World!";
\ No newline at end of file
+let foo :: String = "foo";
+let bar :: String = "bar";
+func join :: (a , b) = {
+    let baz :: String = "yay";
+};
\ No newline at end of file
diff --git a/src/front/lex.rs b/src/front/lex.rs
index f0b629b..ed459c7 100644
--- a/src/front/lex.rs
+++ b/src/front/lex.rs
@@ -34,8 +34,11 @@ syntax! { not_operator      , "!", Token::Not }
 syntax! { typehint_punctuation  , "::", Token::Typehint }
 syntax! { lparen_punctuation    , "(",  Token::LParen }
 syntax! { rparen_punctuation    , ")",  Token::RParen }
+syntax! { lbrace_punctuation    , "{",  Token::LBrace }
+syntax! { rbrace_punctuation    , "}",  Token::RBrace }
 syntax! { semicolon_punctuation , ";",  Token::Semicolon }
 syntax! { colon_punctuation     , ":",  Token::Colon }
+syntax! { comma_punctuation     , ",",  Token::Comma }
 
 // Operator & Punctuation
 fn lex_operator_punctuation(input: &Bytes) -> IResult<&Bytes, Token> {
@@ -50,7 +53,8 @@ fn lex_operator_punctuation(input: &Bytes) -> IResult<&Bytes, Token> {
 
         typehint_punctuation,
         lparen_punctuation, rparen_punctuation,
-        semicolon_punctuation, colon_punctuation,
+        lbrace_punctuation, rbrace_punctuation,
+        semicolon_punctuation, colon_punctuation, comma_punctuation,
     ))(input)
 }
 
diff --git a/src/front/model.rs b/src/front/model.rs
index 3103c23..235efb6 100644
--- a/src/front/model.rs
+++ b/src/front/model.rs
@@ -14,7 +14,9 @@ pub enum Token {
     Plus, Minus, Mul, Div, Not,
     Eq, NEq, Lt, Gt, Lte, Gte,
 
-    LParen, RParen, Semicolon, Colon,
+    LParen, RParen,
+    LBrace, RBrace,
+    Semicolon, Colon, Comma,
 
     If, Else, Let, Func,
 }
diff --git a/src/front/parser.rs b/src/front/parser.rs
index 4fc1b72..c761a1d 100644
--- a/src/front/parser.rs
+++ b/src/front/parser.rs
@@ -2,7 +2,7 @@ use nom::{
     bytes::complete::take,
     combinator::{verify, map},
     Err,
-    IResult, sequence::{terminated, tuple}, multi::many0, branch::alt, error::{Error, ErrorKind},
+    IResult, sequence::{terminated, tuple, pair, preceded, delimited}, multi::many0, branch::alt, error::{Error, ErrorKind},
 };
 
 use super::model::{Token, Tokens, Precedence, Infix, Program, Stmt, Expr, Ident, Literal};
@@ -16,9 +16,15 @@ macro_rules! tag_token (
 );
 
 tag_token!(tag_let, Token::Let);
+tag_token!(tag_func, Token::Func);
 tag_token!(tag_assign, Token::Assign);
 tag_token!(tag_typehint, Token::Typehint);
 tag_token!(tag_semicolon, Token::Semicolon);
+tag_token!(tag_lparen, Token::LParen);
+tag_token!(tag_rparen, Token::RParen);
+tag_token!(tag_lbrace, Token::LBrace);
+tag_token!(tag_rbrace, Token::RBrace);
+tag_token!(tag_comma, Token::Comma);
 tag_token!(tag_end_of_file, Token::EndOfFile);
 
 fn infix_operator(token: &Token) -> (Precedence, Option<Infix>) {
@@ -77,7 +83,7 @@ fn parse_ident_expr(input: Tokens) -> IResult<Tokens, Expr> {
     map(parse_ident, Expr::Ident)(input)
 }
 
-fn parse_let(input: Tokens) -> IResult<Tokens, Stmt> {
+fn parse_let_stmt(input: Tokens) -> IResult<Tokens, Stmt> {
     map(
         tuple((
             tag_let,
@@ -92,6 +98,32 @@ fn parse_let(input: Tokens) -> IResult<Tokens, Stmt> {
     )(input)
 }
 
+fn parse_params(input: Tokens) -> IResult<Tokens, Vec<Ident>> {
+    map(
+        pair(parse_ident, many0(preceded(tag_comma, parse_ident))),
+        |(p, ps)| [&vec![p][..], &ps[..]].concat(),
+    )(input)
+}
+
+fn empty_params(input: Tokens) -> IResult<Tokens, Vec<Ident>> { Ok((input, vec![])) }
+
+fn parse_func_stmt(input: Tokens) -> IResult<Tokens, Stmt> {
+    map(
+        tuple((
+            tag_func,
+            parse_ident,
+            tag_typehint,
+            tag_lparen,
+            alt((parse_params, empty_params)),
+            tag_rparen,
+            tag_assign,
+            parse_block_stmt,
+            tag_semicolon,
+        )),
+        |(_, ident, _, _, params, _, _, block, _)| Stmt::Func(ident, params, block),
+    )(input)
+}
+
 fn parse_expr(input: Tokens, precedence: Precedence, left: Expr) -> IResult<Tokens, Expr> {
     let (i1, t1) = take(1usize)(input)?;
 
@@ -123,9 +155,14 @@ fn parse_expr_lowest(input: Tokens) -> IResult<Tokens, Expr> {
     parse_expr_with(input, Precedence::Lowest)
 }
 
+fn parse_block_stmt(input: Tokens) -> IResult<Tokens, Program> {
+    delimited(tag_lbrace, many0(parse_stmt), tag_rbrace)(input)
+}
+
 fn parse_stmt(input: Tokens) -> IResult<Tokens, Stmt> {
     alt((
-        parse_let,
+        parse_let_stmt,
+        parse_func_stmt,
     ))(input)
 }
 
diff --git a/src/main.rs b/src/main.rs
index b88030b..895aaeb 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -16,8 +16,15 @@ fn main() {
             let bytes: Vec<u8> = fs::read(src).unwrap();
             let (_errs_, tokens) = Lexer::lex_tokens(&bytes).unwrap();
             let tokens = Tokens::new(&tokens);
-            let (_errs_, ast) = Parser::parse(tokens).unwrap();
-            println!("{:#?}", ast);
+            let ast = Parser::parse(tokens);
+            match ast {
+                Ok(ast) => {
+                    println!("{:#?}", ast);
+                }
+                Err(err) => {
+                    println!("{:#?}", err);
+                }
+            }
         },
     }
 }
\ No newline at end of file