607 lines
16 KiB
Rust
607 lines
16 KiB
Rust
extern crate itertools;
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use std::collections::HashMap;
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use std::rc::Rc;
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use std::iter::{Enumerate, Peekable};
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use self::itertools::Itertools;
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use std::vec::IntoIter;
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use std::str::Chars;
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#[derive(Debug, PartialEq, Clone)]
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pub enum TokenType {
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Newline, Semicolon,
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LParen, RParen,
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LSquareBracket, RSquareBracket,
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LAngleBracket, RAngleBracket,
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LCurlyBrace, RCurlyBrace,
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Pipe,
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Comma, Period, Colon, Underscore,
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Operator(Rc<String>),
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DigitGroup(Rc<String>), HexNumberSigil, BinNumberSigil,
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StrLiteral(Rc<String>),
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Identifier(Rc<String>),
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Keyword(Kw),
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EOF,
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Error(String),
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}
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use self::TokenType::*;
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#[derive(Debug, Clone, Copy, PartialEq)]
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pub enum Kw {
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If, Else,
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Func,
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For,
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Match,
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Var, Const, Let, In,
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Alias, Type, SelfType, SelfIdent,
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Trait, Impl,
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True, False
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}
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use self::Kw::*;
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lazy_static! {
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static ref KEYWORDS: HashMap<&'static str, Kw> =
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hashmap! {
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"if" => Kw::If,
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"else" => Kw::Else,
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"fn" => Kw::Func,
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"for" => Kw::For,
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"match" => Kw::Match,
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"var" => Kw::Var,
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"const" => Kw::Const,
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"let" => Kw::Let,
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"in" => Kw::In,
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"alias" => Kw::Alias,
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"type" => Kw::Type,
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"Self" => Kw::SelfType,
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"self" => Kw::SelfIdent,
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"trait" => Kw::Trait,
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"impl" => Kw::Impl,
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"true" => Kw::True,
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"false" => Kw::False,
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};
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}
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#[derive(Debug)]
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pub struct Token {
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token_type: TokenType,
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offset: usize,
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}
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impl Token {
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pub fn get_error(&self) -> Option<&String> {
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match self.token_type {
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TokenType::Error(ref s) => Some(s),
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_ => None,
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}
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}
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}
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fn is_digit(c: &char) -> bool {
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c.is_digit(10)
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}
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type CharIter<'a> = Peekable<Enumerate<Chars<'a>>>;
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pub fn tokenize(input: &str) -> Vec<Token> {
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let mut tokens: Vec<Token> = Vec::new();
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let mut input: CharIter = input.chars().enumerate().peekable();
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while let Some((idx, c)) = input.next() {
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let cur_tok_type = match c {
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'#' => {
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if let Some(&(_, '{')) = input.peek() {
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} else {
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while let Some((_, c)) = input.next() {
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if c == '\n' {
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break;
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}
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}
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}
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continue;
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},
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c if c.is_whitespace() && c != '\n' => continue,
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'\n' => Newline, ';' => Semicolon,
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':' => Colon, ',' => Comma, '.' => Period,
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'(' => LParen, ')' => RParen,
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'{' => LCurlyBrace, '}' => RCurlyBrace,
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'<' => LAngleBracket, '>' => RAngleBracket,
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'[' => LSquareBracket, ']' => RSquareBracket,
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'|' => Pipe,
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'"' => handle_quote(&mut input),
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c if is_digit(&c) => handle_digit(c, &mut input),
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c if c.is_alphabetic() || c == '_' => handle_alphabetic(c, &mut input), //TODO I'll probably have to rewrite this if I care about types being uppercase, also type parameterization
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c => handle_operator(c, &mut input),
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};
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tokens.push(Token { token_type: cur_tok_type, offset: idx });
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}
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tokens
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}
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fn handle_digit(c: char, input: &mut CharIter) -> TokenType {
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if c == '0' && input.peek().map_or(false, |&(_, c)| { c == 'x' }) {
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input.next();
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HexNumberSigil
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} else if c == '0' && input.peek().map_or(false, |&(_, c)| { c == 'b' }) {
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input.next();
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BinNumberSigil
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} else {
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let mut buf = c.to_string();
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buf.extend(input.peeking_take_while(|&(_, ref c)| is_digit(c)).map(|(_, c)| { c }));
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DigitGroup(Rc::new(buf))
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}
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}
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fn handle_quote(input: &mut CharIter) -> TokenType {
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let mut buf = String::new();
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loop {
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match input.next().map(|(_, c)| { c }) {
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Some('"') => break,
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Some('\\') => {
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let next = input.peek().map(|&(_, c)| { c });
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if next == Some('n') {
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input.next();
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buf.push('\n')
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} else if next == Some('"') {
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input.next();
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buf.push('"');
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} else if next == Some('t') {
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input.next();
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buf.push('\t');
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}
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},
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Some(c) => buf.push(c),
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None => return TokenType::Error(format!("Unclosed string")),
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}
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}
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TokenType::StrLiteral(Rc::new(buf))
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}
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fn handle_alphabetic(c: char, input: &mut CharIter) -> TokenType {
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let mut buf = String::new();
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buf.push(c);
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if c == '_' && input.peek().map(|&(_, c)| { !c.is_alphabetic() }).unwrap_or(true) {
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return TokenType::Underscore
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}
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loop {
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match input.peek().map(|&(_, c)| { c }) {
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Some(c) if c.is_alphanumeric() => {
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input.next();
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buf.push(c);
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},
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_ => break,
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}
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}
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match KEYWORDS.get(buf.as_str()) {
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Some(kw) => TokenType::Keyword(kw.clone()),
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None => TokenType::Identifier(Rc::new(buf)),
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}
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}
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fn handle_operator(c: char, input: &mut CharIter) -> TokenType {
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let mut buf = String::new();
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buf.push(c);
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loop {
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match input.peek().map(|&(_, c)| { c }) {
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Some(c) if !c.is_alphabetic() && !c.is_whitespace() => {
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input.next();
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buf.push(c);
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},
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_ => break
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}
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}
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TokenType::Operator(Rc::new(buf))
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}
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#[cfg(test)]
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mod schala_tokenizer_tests {
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use super::*;
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use super::TokenType::*;
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use super::Kw::*;
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macro_rules! digit { ($ident:expr) => { DigitGroup(Rc::new($ident.to_string())) } }
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macro_rules! ident { ($ident:expr) => { Identifier(Rc::new($ident.to_string())) } }
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macro_rules! op { ($ident:expr) => { Operator(Rc::new($ident.to_string())) } }
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#[test]
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fn tokens() {
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let a = tokenize("let a: A<B> = c ++ d");
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let token_types: Vec<TokenType> = a.into_iter().map(move |t| t.token_type).collect();
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assert_eq!(token_types, vec![Keyword(Let), ident!("a"), Colon, ident!("A"),
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LAngleBracket, ident!("B"), RAngleBracket, op!("="), ident!("c"), op!("++"), ident!("d")]);
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}
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#[test]
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fn underscores() {
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let token_types: Vec<TokenType> = tokenize("4_8").into_iter().map(move |t| t.token_type).collect();
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assert_eq!(token_types, vec![digit!("4"), Underscore, digit!("8")]);
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}
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}
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/*
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Schala (PROVISIONAL!!) EBNF grammar
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'' = literal, all other symbols are nonterminals
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program := (statement delimiter ?)*
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delimiter := 'Newline' | ';'
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statement := declaration | expression
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declaration := module | function | type_decl
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type_decl := 'type' type_format
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type_format := 'alias' '=' type | type_constructor
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type_constructor := capital_ident '=' type_rhs
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type_rhs := struct_decl | type_variant ('|' type_variant)*
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struct_decl := 'struct' '{' (ident ':' type)* '}'
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type_variant := capital_ident | tuple_type | capital_ident struct_decl
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tuple_type := // something like Variant(a,b)
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type := // something like Type[A[b]]
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ascription := expression (':' type)+
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function := 'fn' prototype '{' (statement)* '}'
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prototype := identifier '(' identlist ')'
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identlist := identifier (',' identifier)* | ε
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declaration := FN prototype LCurlyBrace (statement)* RCurlyBrace
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prototype := identifier LParen identlist RParen
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identlist := Ident (Comma Ident)* | ε
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exprlist := Expression (Comma Expression)* | ε
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itemlist := Ident COLON Expression (Comma Ident COLON Expression)* | ε
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expression := postop_expression (op postop_expression)*
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postop_expression := primary_expression postop
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primary_expression := number_expr | String | identifier_expr | paren_expr | conditional_expr | while_expr | lambda_expr | list_expr | struct_expr
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number_expr := (PLUS | MINUS ) number_expr | Number
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identifier_expr := call_expression | Variable
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list_expr := LSquareBracket exprlist RSquareBracket
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struct_expr := LCurlyBrace itemlist RCurlyBrace
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call_expression := Identifier LParen exprlist RParen
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while_expr := WHILE primary_expression LCurlyBrace (expression delimiter)* RCurlyBrace
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paren_expr := LParen expression RParen
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conditional_expr := IF expression LCurlyBrace (expression delimiter)* RCurlyBrace (LCurlyBrace (expresion delimiter)* RCurlyBrace)?
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lambda_expr := FN LParen identlist RParen LCurlyBrace (expression delimiter)* RCurlyBrace
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lambda_call := | LParen exprlist RParen
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postop := ε | LParen exprlist RParen | LBracket expression RBracket
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op := '+', '-', etc.
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*/
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/* Schala EBNF Grammar */
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/*
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program := (statement delimiter)* EOF
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delimiter := NEWLINE | SEMICOLON
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statement := expression | declaration
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declaration := type_declaration | func_declaration
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type_declaration := TYPE identifier
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func_declaration := FN identifier LParen param_list RParen
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param_list := (identifier type_anno+ Comma)*
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type_anno := Colon type
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expression := precedence_expr
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precedence_expr := primary
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primary := literal
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literal := TRUE | FALSE | number_literal | str_literal
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identifier := IDENTIFIER
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// a float_literal can still be assigned to an int in type-checking
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number_literal := int_literal | float_literal
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int_literal = (HEX_SIGIL | BIN_SIGIL) digits
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float_literal := digits (PERIOD digits)
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digits := (digit_group underscore)+
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*/
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type TokenIter = Peekable<IntoIter<Token>>;
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#[derive(Debug)]
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pub struct ParseError {
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pub msg: String,
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}
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impl ParseError {
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fn new<T>(msg: &str) -> ParseResult<T> {
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Err(ParseError { msg: msg.to_string() })
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}
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}
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pub type ParseResult<T> = Result<T, ParseError>;
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struct Parser {
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tokens: TokenIter,
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}
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impl Parser {
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fn new(input: Vec<Token>) -> Parser {
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Parser { tokens: input.into_iter().peekable() }
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}
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fn peek(&mut self) -> TokenType {
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self.tokens.peek().map(|ref t| { t.token_type.clone() }).unwrap_or(TokenType::EOF)
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}
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fn next(&mut self) -> TokenType {
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self.tokens.next().map(|ref t| { t.token_type.clone() }).unwrap_or(TokenType::EOF)
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}
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}
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macro_rules! expect {
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($self:expr, $token_type:pat, $message:expr) => {
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match $self.peek() {
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$token_type => $self.next(),
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_ => return Err(ParseError { msg: $message.to_string() }),
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}
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}
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}
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#[derive(Debug, PartialEq)]
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pub struct AST(Vec<Statement>);
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#[derive(Debug, PartialEq)]
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pub enum Statement {
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Expression(Expression),
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Declaration(Declaration),
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}
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#[derive(Debug, PartialEq)]
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pub enum Declaration {
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FuncDecl,
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TypeDecl(Rc<String>, TypeBody)
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}
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#[derive(Debug, PartialEq)]
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pub enum TypeBody {
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TypeBody
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}
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#[derive(Debug, PartialEq)]
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pub enum Expression {
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IntLiteral(u64),
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FloatLiteral(f64),
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BinExp(Operation, Box<Expression>, Box<Expression>)
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}
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#[derive(Debug, PartialEq)]
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pub struct Operation {
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op: Rc<String>
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}
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impl Operation {
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fn min_precedence() -> i32 {
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i32::min_value()
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}
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fn get_precedence(op: Rc<String>) -> i32 {
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let c: char = op.chars().next().unwrap();
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match c {
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'+' | '-' => 10,
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'*' | '/' | '%' => 20,
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_ => 30,
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}
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}
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}
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impl Parser {
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fn program(&mut self) -> ParseResult<AST> {
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let mut statements = Vec::new();
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loop {
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match self.peek() {
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EOF => break,
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Newline | Semicolon => {
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self.next();
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continue;
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},
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_ => statements.push(self.statement()?),
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}
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}
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Ok(AST(statements))
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}
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fn statement(&mut self) -> ParseResult<Statement> {
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//TODO handle error recovery here
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match self.peek() {
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Keyword(Type) => self.type_declaration().map(|decl| { Statement::Declaration(decl) }),
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Keyword(Func)=> self.func_declaration().map(|func| { Statement::Declaration(func) }),
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_ => self.expression().map(|expr| { Statement::Expression(expr) } ),
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}
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}
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fn type_declaration(&mut self) -> ParseResult<Declaration> {
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expect!(self, Keyword(Type), "Expected 'type'");
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let name = self.identifier()?;
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Ok(Declaration::TypeDecl(name, TypeBody::TypeBody))
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}
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fn func_declaration(&mut self) -> ParseResult<Declaration> {
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expect!(self, Keyword(Func), "Expected 'fn'");
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let name = self.identifier()?;
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expect!(self, LParen, "Expected '('");
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let params = self.param_list();
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expect!(self, RParen, "Expected ')'");
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Ok(Declaration::FuncDecl)
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}
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fn param_list(&mut self) -> ParseResult<Vec<Rc<String>>> {
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Ok(vec!())
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}
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fn expression(&mut self) -> ParseResult<Expression> {
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self.precedence_expr(Operation::min_precedence())
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}
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// this implements Pratt parsing, see http://journal.stuffwithstuff.com/2011/03/19/pratt-parsers-expression-parsing-made-easy/
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fn precedence_expr(&mut self, precedence: i32) -> ParseResult<Expression> {
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use self::Expression::*;
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//TODO clean this up
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let mut lhs = self.primary()?;
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loop {
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let op_str = match self.peek() {
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Operator(op) => op,
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_ => break,
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};
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println!("Opstr: {}", op_str);
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let new_precedence = Operation::get_precedence(op_str);
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println!("new {} and old {} precedence", new_precedence, precedence);
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if precedence >= new_precedence {
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break;
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}
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let op_str = match self.next() {
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Operator(op) => op,
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_ => unreachable!(),
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};
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let rhs = self.precedence_expr(new_precedence)?;
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let operation = Operation { op: op_str };
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lhs = BinExp(operation, Box::new(lhs), Box::new(rhs));
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}
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Ok(lhs)
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}
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fn primary(&mut self) -> ParseResult<Expression> {
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self.literal()
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}
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fn identifier(&mut self) -> ParseResult<Rc<String>> {
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match self.next() {
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Identifier(s) => Ok(s),
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p => ParseError::new(&format!("Expected an identifier, got {:?}", p)),
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}
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}
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fn literal(&mut self) -> ParseResult<Expression> {
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match self.peek() {
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DigitGroup(_) | HexNumberSigil | BinNumberSigil | Period => self.number_literal(),
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t => panic!("trying to parse {:?}", t),
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}
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}
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fn number_literal(&mut self) -> ParseResult<Expression> {
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match self.peek() {
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HexNumberSigil | BinNumberSigil => self.int_literal(),
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_ => self.float_literal(),
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}
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}
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fn int_literal(&mut self) -> ParseResult<Expression> {
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use self::Expression::*;
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match self.next() {
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BinNumberSigil => {
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let digits = self.digits()?;
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let n = parse_binary(digits)?;
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Ok(IntLiteral(n))
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},
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HexNumberSigil => {
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unimplemented!()
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},
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_ => return ParseError::new("Expected '0x' or '0b'"),
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}
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}
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fn float_literal(&mut self) -> ParseResult<Expression> {
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use self::Expression::*;
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let mut digits = self.digits()?;
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if let TokenType::Period = self.peek() {
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self.next();
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digits.push_str(".");
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digits.push_str(&self.digits()?);
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match digits.parse::<f64>() {
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Ok(f) => Ok(FloatLiteral(f)),
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Err(e) => unimplemented!("Float didn't parse with error: {}", e),
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}
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} else {
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match digits.parse::<u64>() {
|
|
Ok(d) => Ok(IntLiteral(d)),
|
|
Err(e) => unimplemented!("Need to handle numbers that don't parse to a Rust u64 {}", e),
|
|
}
|
|
}
|
|
}
|
|
|
|
fn digits(&mut self) -> ParseResult<String> {
|
|
let mut ds = String::new();
|
|
loop {
|
|
match self.peek() {
|
|
Underscore => { self.next(); continue; },
|
|
DigitGroup(ref s) => { self.next(); ds.push_str(s)},
|
|
_ => break,
|
|
}
|
|
}
|
|
Ok(ds)
|
|
}
|
|
}
|
|
|
|
fn parse_binary(digits: String) -> ParseResult<u64> {
|
|
let mut result: u64 = 0;
|
|
let mut multiplier = 1;
|
|
for d in digits.chars().rev() {
|
|
match d {
|
|
'1' => result += multiplier,
|
|
'0' => (),
|
|
_ => return ParseError::new("Encountered a character not '1' or '0 while parsing a binary literal"),
|
|
}
|
|
multiplier *= 2;
|
|
}
|
|
Ok(result)
|
|
}
|
|
|
|
pub fn parse(input: Vec<Token>) -> Result<AST, ParseError> {
|
|
let mut parser = Parser::new(input);
|
|
parser.program()
|
|
}
|
|
|
|
#[cfg(test)]
|
|
mod parse_tests {
|
|
use super::*;
|
|
use super::Statement::*;
|
|
use super::Expression::*;
|
|
use super::ParseError;
|
|
|
|
macro_rules! parse_test {
|
|
($string:expr, $correct:expr) => { assert_eq!(parse(tokenize($string)).unwrap(), $correct) }
|
|
}
|
|
macro_rules! binexp {
|
|
($op:expr, $lhs:expr, $rhs:expr) => { BinExp($op, Box::new($lhs), Box::new($rhs)) }
|
|
}
|
|
macro_rules! op {
|
|
($op:expr) => { Operation { op: Rc::new($op.to_string()) } }
|
|
}
|
|
|
|
#[test]
|
|
fn test_parsing() {
|
|
parse_test!("8.1", AST(vec![Expression(FloatLiteral(8.1))]));
|
|
parse_test!("0b010", AST(vec![Expression(IntLiteral(2))]));
|
|
parse_test!("3; 4; 4.3", AST(
|
|
vec![Expression(IntLiteral(3)), Expression(IntLiteral(4)),
|
|
Expression(FloatLiteral(4.3))]));
|
|
|
|
parse_test!("1 + 2 * 3", AST(vec!
|
|
[
|
|
Expression(binexp!(op!("+"), IntLiteral(1), binexp!(op!("*"), IntLiteral(2), IntLiteral(3))))
|
|
]));
|
|
|
|
parse_test!("1 * 2 + 3", AST(vec!
|
|
[
|
|
Expression(binexp!(op!("+"), binexp!(op!("*"), IntLiteral(1), IntLiteral(2)), IntLiteral(3)))
|
|
]));
|
|
|
|
parse_test!("1 && 2", AST(vec![Expression(binexp!(op!("&&"), IntLiteral(1), IntLiteral(2)))]));
|
|
|
|
|
|
}
|
|
}
|