some AST generation (let, ident, etc.)

also no more formal commit message because im lazy

example/hello_world.hyc

@@ -1,3 +1,2 @@
-let msg :: String = "Hello, World";
-func add2 :: (a: Int, b: Int) -> Int = a + b;
-func main :: () = puts (msg);
+let foo :: String = "Hello, ";
+let bar :: String = "World!";

src/front/mod.rs

@@ -1,4 +1,5 @@
 pub mod model;
 pub mod helper;
 
-pub mod lex;
+pub mod lex;
+pub mod parser;

src/front/model.rs

@@ -1,3 +1,7 @@
+use std::iter::Enumerate;
+
+use nom::{InputTake, Needed, InputIter, InputLength};
+
 #[derive(Clone, Debug, PartialEq)]
 pub enum Token {
     Illegal, EndOfFile,
@@ -26,4 +30,125 @@ impl<'a> Tokens<'a> {
     pub fn new(tokens: &'a [Token]) -> Self {
         Tokens { tokens, start: 0, end: tokens.len(), }
     }
+}
+
+impl<'a> InputTake for Tokens<'a> {
+    #[inline]
+    fn take(&self, count: usize) -> Self {
+        Tokens {
+            tokens: &self.tokens[0..count],
+            start: 0,
+            end: count,
+        }
+    }
+
+    #[inline]
+    fn take_split(&self, count: usize) -> (Self, Self) {
+        let (prefix, suffix) = self.tokens.split_at(count);
+        let first = Tokens {
+            tokens: prefix,
+            start: 0,
+            end: prefix.len(),
+        };
+        let second = Tokens {
+            tokens: suffix,
+            start: 0,
+            end: suffix.len(),
+        };
+        (second, first)
+    }
+}
+
+impl<'a> InputLength for Tokens<'a> {
+    #[inline]
+    fn input_len(&self) -> usize {
+        self.tokens.len()
+    }
+}
+
+impl<'a> InputIter for Tokens<'a> {
+    type Item = &'a Token;
+    type Iter = Enumerate<::std::slice::Iter<'a, Token>>;
+    type IterElem = ::std::slice::Iter<'a, Token>;
+
+    #[inline]
+    fn iter_indices(&self) -> Enumerate<::std::slice::Iter<'a, Token>> {
+        self.tokens.iter().enumerate()
+    }
+
+    #[inline]
+    fn iter_elements(&self) -> ::std::slice::Iter<'a, Token> {
+        self.tokens.iter()
+    }
+
+    #[inline]
+    fn position<P>(&self, predicate: P) -> Option<usize>
+    where P: Fn(Self::Item) -> bool {
+        self.tokens.iter().position(predicate)
+    }
+
+    #[inline]
+    fn slice_index(&self, count: usize) -> Result<usize, Needed> {
+        if self.tokens.len() >= count { Ok(count) }
+        else { Err(Needed::Unknown) }
+    }
+}
+
+pub type Program = Vec<Stmt>;
+
+#[derive(Clone, Debug, PartialEq)]
+pub enum Stmt {
+    Let(Ident, Ident, Expr),
+    Func(Ident, Vec<Ident>, Vec<Stmt>),
+}
+
+#[derive(Clone, Debug, PartialEq)]
+pub enum Expr {
+    Ident(Ident), Literal(Literal),
+    Array(Vec<Expr>),
+    Prefix(Prefix, Box<Expr>),
+    Infix(Infix, Box<Expr>, Box<Expr>),
+    If {
+        cond: Box<Expr>,
+        then: Program,
+        else_: Option<Program>,
+    },
+    Func {
+        name: Ident,
+        args: Vec<Ident>,
+        body: Program,
+    },
+    Call {
+        func: Box<Expr>,
+        args: Vec<Expr>,
+    },
+}
+
+#[derive(Clone, Debug, PartialEq)]
+pub enum Literal {
+    Int(i64), Bool(bool), String(String),
+}
+
+#[derive(Clone, Debug, PartialEq)]
+pub struct Ident(pub String);
+
+#[derive(Clone, Debug, PartialEq)]
+pub enum Prefix {
+    Not,
+}
+
+#[derive(Clone, Debug, PartialEq)]
+pub enum Infix {
+    Plus, Minus, Mul, Div,
+    Eq, NEq, Lt, Gt, Lte, Gte,
+}
+
+#[derive(Clone, Debug, PartialEq, PartialOrd)]
+pub enum Precedence {
+    Lowest,
+    Equals,
+    LessGreater,
+    Sum,
+    Product,
+    Call,
 }

src/front/parser.rs

@@ -0,0 +1,142 @@
+use nom::{
+    bytes::complete::take,
+    combinator::{verify, map},
+    Err,
+    IResult, sequence::{terminated, tuple}, multi::many0, branch::alt, error::{Error, ErrorKind},
+};
+
+use super::model::{Token, Tokens, Precedence, Infix, Program, Stmt, Expr, Ident, Literal};
+
+macro_rules! tag_token (
+    ($func_name:ident, $tag: expr) => (
+        fn $func_name(tokens: Tokens) -> IResult<Tokens, Tokens> {
+            verify(take(1usize), |t: &Tokens| t.tokens[0] == $tag)(tokens)
+        }
+    )
+);
+
+tag_token!(tag_let, Token::Let);
+tag_token!(tag_assign, Token::Assign);
+tag_token!(tag_typehint, Token::Typehint);
+tag_token!(tag_semicolon, Token::Semicolon);
+tag_token!(tag_end_of_file, Token::EndOfFile);
+
+fn infix_operator(token: &Token) -> (Precedence, Option<Infix>) {
+    match *token {
+        Token::Eq => (Precedence::Equals, Some(Infix::Eq)),
+        Token::NEq => (Precedence::Equals, Some(Infix::NEq)),
+        Token::Lt => (Precedence::LessGreater, Some(Infix::Lt)),
+        Token::Gt => (Precedence::LessGreater, Some(Infix::Gt)),
+        Token::Lte => (Precedence::LessGreater, Some(Infix::Lte)),
+        Token::Gte => (Precedence::LessGreater, Some(Infix::Gte)),
+        Token::Plus => (Precedence::Sum, Some(Infix::Plus)),
+        Token::Minus => (Precedence::Sum, Some(Infix::Minus)),
+        Token::Mul => (Precedence::Product, Some(Infix::Mul)),
+        Token::Div => (Precedence::Product, Some(Infix::Div)),
+        Token::LParen => (Precedence::Call, None),
+        _ => (Precedence::Lowest, None),
+    }
+}
+
+fn parse_literal(input: Tokens) -> IResult<Tokens, Literal> {
+    let (i1, t1) = take(1usize)(input)?;
+    if t1.tokens.is_empty() { Err(Err::Error(Error::new(input, ErrorKind::Tag))) }
+    else {
+        match t1.tokens[0].clone() {
+            Token::Int(i) => Ok((i1, Literal::Int(i))),
+            Token::String(s) => Ok((i1, Literal::String(s))),
+            Token::Bool(b) => Ok((i1, Literal::Bool(b))),
+            _ => Err(Err::Error(Error::new(input, ErrorKind::Tag))),
+        }
+    }
+}
+
+fn parse_literal_expr(input: Tokens) -> IResult<Tokens, Expr> {
+    map(parse_literal, Expr::Literal)(input)
+}
+
+fn parse_atom_expr(input: Tokens) -> IResult<Tokens, Expr> {
+    alt((
+        parse_literal_expr,
+        parse_ident_expr,
+    ))(input)
+}
+ 
+fn parse_ident(input: Tokens) -> IResult<Tokens, Ident> {
+    let (i1, t1) = take(1usize)(input)?;
+    if t1.tokens.is_empty() { Err(Err::Error(Error::new(input, ErrorKind::Tag))) }
+    else {
+        match t1.tokens[0].clone() {
+            Token::Identifier(name) => Ok((i1, Ident(name))),
+            _ => Err(Err::Error(Error::new(input, ErrorKind::Tag))),
+        }
+    }
+}
+
+fn parse_ident_expr(input: Tokens) -> IResult<Tokens, Expr> {
+    map(parse_ident, Expr::Ident)(input)
+}
+
+fn parse_let(input: Tokens) -> IResult<Tokens, Stmt> {
+    map(
+        tuple((
+            tag_let,
+            parse_ident,
+            tag_typehint,
+            parse_ident,
+            tag_assign,
+            parse_expr_lowest,
+            tag_semicolon,
+        )),
+        |(_, ident, _, typehint, _, expr, _)| Stmt::Let(ident, typehint, expr),
+    )(input)
+}
+
+fn parse_expr(input: Tokens, precedence: Precedence, left: Expr) -> IResult<Tokens, Expr> {
+    let (i1, t1) = take(1usize)(input)?;
+
+    if t1.tokens.is_empty() { Ok((i1, left)) }
+    else {
+        let p = infix_operator(&t1.tokens[0]);
+        match p {
+            (Precedence::Call, _) if precedence < Precedence::Call => {
+                // let (i2, left2) = parse_call_expr(input, left)?;
+                // parse_expr(i2, precedence, left2)
+                todo!()
+            },
+            (ref peek, _) if precedence < *peek => {
+                // let (i2, left2) = parse_infix_expr(input, left)?;
+                // parse_expr(i2, precedence, left2)
+                todo!()
+            },
+            _ => Ok((input, left)),
+        }
+    }
+}
+
+fn parse_expr_with(input: Tokens, precedence: Precedence) -> IResult<Tokens, Expr> {
+    let (i1, left) = parse_atom_expr(input)?;
+    parse_expr(i1, precedence, left)
+}
+
+fn parse_expr_lowest(input: Tokens) -> IResult<Tokens, Expr> {
+    parse_expr_with(input, Precedence::Lowest)
+}
+
+fn parse_stmt(input: Tokens) -> IResult<Tokens, Stmt> {
+    alt((
+        parse_let,
+    ))(input)
+}
+
+fn parse_program(input: Tokens) -> IResult<Tokens, Program> {
+    terminated(many0(parse_stmt), tag_end_of_file)(input)
+}
+
+pub struct Parser;
+
+impl Parser {
+    pub fn parse(tokens: Tokens) -> IResult<Tokens, Program> {
+        parse_program(tokens)
+    }
+}

src/main.rs

@@ -7,15 +7,17 @@ pub mod args;
 use args::{Args, Options};
 
 pub mod front;
-use front::lex::Lexer;
+use front::{lex::Lexer, parser::Parser, model::Tokens};
 
 fn main() {
     let args = Args::parse();
     match args.options {
         Options::Compile { input: src, ast: _print_ast } => {
             let bytes: Vec<u8> = fs::read(src).unwrap();
-            let tokens = Lexer::lex_tokens(&bytes);
-            println!("{:?}", tokens);
+            let (_errs_, tokens) = Lexer::lex_tokens(&bytes).unwrap();
+            let tokens = Tokens::new(&tokens);
+            let (_errs_, ast) = Parser::parse(tokens).unwrap();
+            println!("{:#?}", ast);
         },
     }
 }