1025 lines
29 KiB
Rust
1025 lines
29 KiB
Rust
use itertools::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 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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Return,
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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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"return" => Kw::Return,
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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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pub token_type: TokenType,
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pub 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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const OPERATOR_CHARS: [char; 19] = ['!', '$', '%', '&', '*', '+', '-', '.', '/', ':', '<', '>', '=', '?', '@', '^', '|', '~', '`'];
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fn is_operator(c: &char) -> bool {
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OPERATOR_CHARS.iter().any(|x| x == c)
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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,
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'(' => LParen, ')' => RParen,
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'{' => LCurlyBrace, '}' => RCurlyBrace,
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'[' => LSquareBracket, ']' => RSquareBracket,
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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 if is_operator(&c) => handle_operator(c, &mut input),
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unknown => Error(format!("Unexpected character: {}", unknown)),
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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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match c {
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'<' | '>' | '|' | '.' => {
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let ref next = input.peek().map(|&(_, c)| { c });
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if !next.map(|n| { is_operator(&n) }).unwrap_or(false) {
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return match c {
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'<' => LAngleBracket,
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'>' => RAngleBracket,
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'|' => Pipe,
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'.' => Period,
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_ => unreachable!(),
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}
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}
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},
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_ => (),
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};
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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 is_operator(&c) => {
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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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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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/* for reference, here is the scala EBNF for expressions:
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* see http://scala-lang.org/files/archive/spec/2.12/06-expressions.html
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Expr ::= (Bindings | id | ‘_’) ‘=>’ Expr
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| Expr1
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Expr1 ::= ‘if’ ‘(’ Expr ‘)’ {nl} Expr [[semi] else Expr]
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| ‘while’ ‘(’ Expr ‘)’ {nl} Expr
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| ‘try’ ‘{’ Block ‘}’ [‘catch’ ‘{’ CaseClauses ‘}’]
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[‘finally’ Expr]
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| ‘do’ Expr [semi] ‘while’ ‘(’ Expr ’)’
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| ‘for’ (‘(’ Enumerators ‘)’ | ‘{’ Enumerators ‘}’)
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{nl} [‘yield’] Expr
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| ‘throw’ Expr
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| ‘return’ [Expr]
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| [SimpleExpr ‘.’] id ‘=’ Expr
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| SimpleExpr1 ArgumentExprs ‘=’ Expr
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| PostfixExpr
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| PostfixExpr Ascription
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| PostfixExpr ‘match’ ‘{’ CaseClauses ‘}’
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PrefixExpr ::= [‘-’ | ‘+’ | ‘~’ | ‘!’] SimpleExpr
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*/
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/* Schala EBNF Grammar */
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/* Terminal productions are in 'single quotes' or UPPERCASE if they are a class
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* or not representable in ASCII
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program := (statement delimiter)* EOF
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delimiter := NEWLINE | ';'
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statement := expression | declaration
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declaration := type_alias | type_declaration | func_declaration | binding_declaration
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type_alias := 'alias' IDENTIFIER '=' IDENTIFIER
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type_declaration := 'type' IDENTIFIER '=' type_body
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type_body := variant_specifier ('|' variant_specifier)*
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variant_specifier := '{' member_list '}'
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member_list := (IDENTIFIER type_anno)*
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func_declaration := 'fn' IDENTIFIER '(' param_list ')'
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param_list := (IDENTIFIER type_anno+ ',')*
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binding_declaration: 'var' IDENTIFIER '=' expression
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| 'const' IDENTIFIER '=' expression
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type_anno := ':' type
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type := IDENTIFIER (LAngleBracket type RAngleBracket)*
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expression := precedence_expr type_anno+
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precedence_expr := prefix_expr
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prefix_expr := prefix_op primary
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prefix_op := '+' | '-' | '!' | '~'
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primary := literal | paren_expr | if_expr | match_expr | identifier_expr
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paren_expr := LParen expression RParen
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identifier_expr := call_expr | index_expr | IDENTIFIER
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literal := 'true' | 'false' | number_literal | STR_LITERAL
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if_expr := 'if' expression block else_clause
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else_clause := ε | 'else' block
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match_expr := 'match' expression '{' match_body '}'
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match_body := pattern '=>' expression
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pattern := identifier //TODO NOT DONE
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block := '{' (statement)* '}'
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||
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call_expr := IDENTIFIER '(' expr_list ')' //TODO maybe make this optional? or no, have a bare identifier meant to be used as method taken care of in eval
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index_expr := '[' (expression (',' (expression)* | ε) ']'
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expr_list := expression (',' expression)* | ε
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||
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||
|
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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 = ('0x' | '0b') digits
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float_literal := digits ('.' 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)]
|
||
pub struct ParseError {
|
||
pub msg: String,
|
||
}
|
||
|
||
impl ParseError {
|
||
fn new<T>(msg: &str) -> ParseResult<T> {
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||
Err(ParseError { msg: msg.to_string() })
|
||
}
|
||
}
|
||
|
||
pub type ParseResult<T> = Result<T, ParseError>;
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||
|
||
#[derive(Debug)]
|
||
pub struct ParseRecord {
|
||
production_name: String,
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||
next_token: String,
|
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}
|
||
|
||
struct Parser {
|
||
tokens: TokenIter,
|
||
parse_record: Vec<ParseRecord>,
|
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}
|
||
|
||
impl Parser {
|
||
fn new(input: Vec<Token>) -> Parser {
|
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Parser { tokens: input.into_iter().peekable(), parse_record: vec![] }
|
||
}
|
||
|
||
fn peek(&mut self) -> TokenType {
|
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self.tokens.peek().map(|ref t| { t.token_type.clone() }).unwrap_or(TokenType::EOF)
|
||
}
|
||
|
||
fn next(&mut self) -> TokenType {
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self.tokens.next().map(|ref t| { t.token_type.clone() }).unwrap_or(TokenType::EOF)
|
||
}
|
||
}
|
||
|
||
macro_rules! expect {
|
||
($self:expr, $token_type:pat, $message:expr) => {
|
||
match $self.peek() {
|
||
$token_type => $self.next(),
|
||
_ => return Err(ParseError { msg: $message.to_string() }),
|
||
}
|
||
};
|
||
($self:expr, $token_type:pat if $cond:expr, $message:expr) => {
|
||
match $self.peek() {
|
||
$token_type if $cond => $self.next(),
|
||
_ => return Err(ParseError { msg: $message.to_string() }),
|
||
}
|
||
}
|
||
}
|
||
|
||
#[derive(Debug, PartialEq)]
|
||
pub struct AST(Vec<Statement>);
|
||
|
||
#[derive(Debug, PartialEq)]
|
||
pub enum Statement {
|
||
Expression(Expression),
|
||
Declaration(Declaration),
|
||
}
|
||
|
||
type ParamName = Rc<String>;
|
||
type TypeName = Rc<String>;
|
||
type FormalParamList = Vec<(ParamName, Option<TypeName>)>;
|
||
|
||
#[derive(Debug, PartialEq)]
|
||
pub enum Declaration {
|
||
FuncDecl {
|
||
name: Rc<String>,
|
||
params: FormalParamList,
|
||
},
|
||
TypeDecl(Rc<String>, TypeBody),
|
||
TypeAlias(Rc<String>, Rc<String>),
|
||
Binding {
|
||
name: Rc<String>,
|
||
constant: bool,
|
||
expr: Expression,
|
||
}
|
||
}
|
||
|
||
#[derive(Debug, PartialEq)]
|
||
pub struct TypeBody(Vec<Variant>);
|
||
|
||
#[derive(Debug, PartialEq)]
|
||
pub enum Variant {
|
||
Singleton(Rc<String>),
|
||
//ArgumentConstructor,
|
||
//Record
|
||
}
|
||
|
||
#[derive(Debug, PartialEq)]
|
||
pub enum Expression {
|
||
IntLiteral(u64),
|
||
FloatLiteral(f64),
|
||
StringLiteral(Rc<String>),
|
||
BoolLiteral(bool),
|
||
BinExp(Operation, Box<Expression>, Box<Expression>),
|
||
PrefixExp(Operation, Box<Expression>),
|
||
Variable(Rc<String>),
|
||
Call {
|
||
name: Rc<String>,
|
||
params: Vec<Expression>,
|
||
},
|
||
Index {
|
||
indexee: Box<Expression>,
|
||
indexers: Vec<Expression>,
|
||
},
|
||
IfExpression(Box<Expression>, Vec<Statement>, Option<Vec<Statement>>),
|
||
MatchExpression(Box<Expression>, Vec<MatchArm>)
|
||
}
|
||
|
||
#[derive(Debug, PartialEq)]
|
||
pub struct MatchArm {
|
||
pat: Pattern,
|
||
expr: Expression,
|
||
}
|
||
|
||
#[derive(Debug, PartialEq)]
|
||
pub struct Pattern(Rc<String>);
|
||
|
||
#[derive(Debug, PartialEq)]
|
||
pub struct Operation(Rc<String>);
|
||
|
||
impl Operation {
|
||
fn min_precedence() -> i32 {
|
||
i32::min_value()
|
||
}
|
||
|
||
fn get_precedence(op: &str) -> i32 {
|
||
match op {
|
||
"+" | "-" => 10,
|
||
"*" | "/" | "%" => 20,
|
||
_ => 30,
|
||
}
|
||
}
|
||
|
||
fn is_prefix(op: &str) -> bool {
|
||
match op {
|
||
"+" | "-" | "!" | "~" => true,
|
||
_ => false,
|
||
}
|
||
}
|
||
}
|
||
|
||
macro_rules! parse_method {
|
||
($name:ident(&mut $self:ident) -> $type:ty $body:block) => {
|
||
fn $name(&mut $self) -> $type {
|
||
let next_token = $self.peek();
|
||
let record = ParseRecord {
|
||
production_name: stringify!($name).to_string(),
|
||
next_token: format!("{:?}", next_token),
|
||
};
|
||
$self.parse_record.push(record);
|
||
$body
|
||
}
|
||
};
|
||
}
|
||
|
||
impl Parser {
|
||
parse_method!(program(&mut self) -> ParseResult<AST> {
|
||
let mut statements = Vec::new();
|
||
loop {
|
||
match self.peek() {
|
||
EOF => break,
|
||
Newline | Semicolon => {
|
||
self.next();
|
||
continue;
|
||
},
|
||
_ => statements.push(self.statement()?),
|
||
}
|
||
}
|
||
Ok(AST(statements))
|
||
});
|
||
|
||
parse_method!(statement(&mut self) -> ParseResult<Statement> {
|
||
//TODO handle error recovery here
|
||
match self.peek() {
|
||
Keyword(Alias) => self.type_alias().map(|alias| { Statement::Declaration(alias) }),
|
||
Keyword(Type) => self.type_declaration().map(|decl| { Statement::Declaration(decl) }),
|
||
Keyword(Func)=> self.func_declaration().map(|func| { Statement::Declaration(func) }),
|
||
Keyword(Var) | Keyword(Const) => self.binding_declaration().map(|decl| Statement::Declaration(decl)),
|
||
_ => self.expression().map(|expr| { Statement::Expression(expr) } ),
|
||
}
|
||
});
|
||
|
||
parse_method!(type_alias(&mut self) -> ParseResult<Declaration> {
|
||
expect!(self, Keyword(Alias), "Expected 'alias'");
|
||
let alias = self.identifier()?;
|
||
expect!(self, Operator(ref c) if **c == "=", "Expected '='");
|
||
let original = self.identifier()?;
|
||
Ok(Declaration::TypeAlias(alias, original))
|
||
});
|
||
|
||
parse_method!(type_declaration(&mut self) -> ParseResult<Declaration> {
|
||
expect!(self, Keyword(Type), "Expected 'type'");
|
||
let name = self.identifier()?;
|
||
expect!(self, Operator(ref c) if **c == "=", "Expected '='");
|
||
let body = self.type_body()?;
|
||
Ok(Declaration::TypeDecl(name, body))
|
||
});
|
||
|
||
parse_method!(type_body(&mut self) -> ParseResult<TypeBody> {
|
||
let variant = Variant::Singleton(self.identifier()?);
|
||
Ok(TypeBody(vec!(variant)))
|
||
});
|
||
|
||
parse_method!(func_declaration(&mut self) -> ParseResult<Declaration> {
|
||
expect!(self, Keyword(Func), "Expected 'fn'");
|
||
let name = self.identifier()?;
|
||
expect!(self, LParen, "Expected '('");
|
||
let params = self.param_list()?;
|
||
expect!(self, RParen, "Expected ')'");
|
||
let decl = Declaration::FuncDecl {
|
||
name: name,
|
||
params: params
|
||
};
|
||
Ok(decl)
|
||
});
|
||
|
||
parse_method!(param_list(&mut self) -> ParseResult<FormalParamList> {
|
||
Ok(vec!())
|
||
});
|
||
|
||
parse_method!(binding_declaration(&mut self) -> ParseResult<Declaration> {
|
||
let constant = match self.next() {
|
||
Keyword(Var) => false,
|
||
Keyword(Const) => true,
|
||
_ => return ParseError::new("Expected 'var' or 'const'"),
|
||
};
|
||
let name = self.identifier()?;
|
||
expect!(self, Operator(ref o) if **o == "=", "Expected '='");
|
||
let expr = self.expression()?;
|
||
|
||
Ok(Declaration::Binding { name, constant, expr })
|
||
});
|
||
|
||
parse_method!(expression(&mut self) -> ParseResult<Expression> {
|
||
let expr_body = self.precedence_expr(Operation::min_precedence());
|
||
let type_anno = match self.peek() {
|
||
Colon => {
|
||
self.next();
|
||
Some(self.type_anno()?)
|
||
},
|
||
_ => None
|
||
};
|
||
expr_body
|
||
});
|
||
|
||
parse_method!(type_anno(&mut self) -> ParseResult<()> {
|
||
let type_name = self.identifier()?;
|
||
let param = match self.peek() {
|
||
LAngleBracket => {
|
||
self.next();
|
||
let param = self.type_anno()?;
|
||
expect!(self, RAngleBracket, "Expected '>'");
|
||
Some(param)
|
||
},
|
||
_ => None
|
||
};
|
||
Ok(())
|
||
});
|
||
|
||
// this implements Pratt parsing, see http://journal.stuffwithstuff.com/2011/03/19/pratt-parsers-expression-parsing-made-easy/
|
||
fn precedence_expr(&mut self, precedence: i32) -> ParseResult<Expression> {
|
||
use self::Expression::*;
|
||
|
||
let next_token = self.peek();
|
||
let record = ParseRecord {
|
||
production_name: "precedence_expr".to_string(),
|
||
next_token: format!("{:?}", next_token),
|
||
};
|
||
self.parse_record.push(record);
|
||
|
||
let mut lhs = self.prefix_expr()?;
|
||
loop {
|
||
let new_precedence = match self.peek() {
|
||
Operator(op) => Operation::get_precedence(&*op),
|
||
Period => Operation::get_precedence("."),
|
||
_ => break,
|
||
};
|
||
|
||
if precedence >= new_precedence {
|
||
break;
|
||
}
|
||
let op_str = match self.next() {
|
||
Operator(op) => op,
|
||
Period => Rc::new(".".to_string()),
|
||
_ => unreachable!(),
|
||
};
|
||
let rhs = self.precedence_expr(new_precedence)?;
|
||
let operation = Operation(op_str);
|
||
lhs = BinExp(operation, Box::new(lhs), Box::new(rhs));
|
||
}
|
||
Ok(lhs)
|
||
}
|
||
|
||
parse_method!(prefix_expr(&mut self) -> ParseResult<Expression> {
|
||
match self.peek() {
|
||
Operator(ref op) if Operation::is_prefix(&*op) => {
|
||
let op_str = match self.next() {
|
||
Operator(op) => op,
|
||
_ => unreachable!(),
|
||
};
|
||
let expr = self.primary()?;
|
||
Ok(Expression::PrefixExp(Operation(op_str), Box::new(expr)))
|
||
},
|
||
_ => self.primary()
|
||
}
|
||
});
|
||
|
||
parse_method!(primary(&mut self) -> ParseResult<Expression> {
|
||
match self.peek() {
|
||
LParen => self.paren_expr(),
|
||
Keyword(Kw::If) => self.if_expr(),
|
||
Keyword(Kw::Match) => self.match_expr(),
|
||
Identifier(_) => self.identifier_expr(),
|
||
_ => self.literal(),
|
||
}
|
||
});
|
||
|
||
parse_method!(paren_expr(&mut self) -> ParseResult<Expression> {
|
||
expect!(self, LParen, "Expected '('");
|
||
let expr = self.expression()?;
|
||
expect!(self, RParen, "Expected ')'");
|
||
Ok(expr)
|
||
});
|
||
|
||
parse_method!(identifier_expr(&mut self) -> ParseResult<Expression> {
|
||
let identifier = self.identifier()?;
|
||
match self.peek() {
|
||
LParen => {
|
||
let call_params = self.call_expr()?;
|
||
Ok(Expression::Call {
|
||
name: identifier,
|
||
params: call_params,
|
||
})
|
||
},
|
||
LSquareBracket => {
|
||
let indexers = self.index_expr()?;
|
||
Ok(Expression::Index {
|
||
indexee: Box::new(Expression::Variable(identifier)),
|
||
indexers: indexers,
|
||
})
|
||
}
|
||
_ => Ok(Expression::Variable(identifier))
|
||
}
|
||
});
|
||
|
||
parse_method!(call_expr(&mut self) -> ParseResult<Vec<Expression>> {
|
||
let mut exprs = Vec::new();
|
||
expect!(self, LParen, "Expected '('");
|
||
loop {
|
||
if let RParen = self.peek() {
|
||
break;
|
||
}
|
||
exprs.push(self.expression()?);
|
||
match self.peek() {
|
||
Comma => { self.next(); },
|
||
_ => break,
|
||
}
|
||
}
|
||
expect!(self, RParen, "Expected ')'");
|
||
Ok(exprs)
|
||
});
|
||
|
||
parse_method!(index_expr(&mut self) -> ParseResult<Vec<Expression>> {
|
||
expect!(self, LSquareBracket, "Expected '['");
|
||
let mut exprs = Vec::new();
|
||
loop {
|
||
if let RSquareBracket = self.peek() {
|
||
break;
|
||
}
|
||
exprs.push(self.expression()?);
|
||
match self.peek() {
|
||
Comma => { self.next(); }
|
||
_ => break,
|
||
};
|
||
}
|
||
expect!(self, RSquareBracket, "Expected ']'");
|
||
Ok(exprs)
|
||
});
|
||
|
||
parse_method!(if_expr(&mut self) -> ParseResult<Expression> {
|
||
expect!(self, Keyword(Kw::If), "Expected 'if'");
|
||
let condition = self.expression()?;
|
||
let then_clause = self.block()?;
|
||
let else_clause = self.else_clause()?;
|
||
Ok(Expression::IfExpression(Box::new(condition), then_clause, else_clause))
|
||
});
|
||
|
||
parse_method!(else_clause(&mut self) -> ParseResult<Option<Vec<Statement>>> {
|
||
Ok(if let Keyword(Kw::Else) = self.peek() {
|
||
self.next();
|
||
Some(self.block()?)
|
||
} else {
|
||
None
|
||
})
|
||
});
|
||
|
||
parse_method!(block(&mut self) -> ParseResult<Vec<Statement>> {
|
||
expect!(self, LCurlyBrace, "Expected '{'");
|
||
let mut statements = Vec::new();
|
||
loop {
|
||
match self.peek() {
|
||
EOF | RCurlyBrace => break,
|
||
Newline | Semicolon => {
|
||
self.next();
|
||
continue;
|
||
},
|
||
_ => statements.push(self.statement()?),
|
||
}
|
||
}
|
||
expect!(self, RCurlyBrace, "Expected '}'");
|
||
Ok(statements)
|
||
});
|
||
|
||
parse_method!(match_expr(&mut self) -> ParseResult<Expression> {
|
||
expect!(self, Keyword(Kw::Match), "Expected 'match'");
|
||
let expr = self.expression()?;
|
||
expect!(self, LCurlyBrace, "Expected '{'");
|
||
let body = self.match_body()?;
|
||
expect!(self, RCurlyBrace, "Expected '}'");
|
||
Ok(Expression::MatchExpression(Box::new(expr), body))
|
||
});
|
||
|
||
parse_method!(match_body(&mut self) -> ParseResult<Vec<MatchArm>> {
|
||
let mut arms = Vec::new();
|
||
loop {
|
||
if let RCurlyBrace = self.peek() {
|
||
break;
|
||
}
|
||
let pat = self.pattern()?;
|
||
expect!(self, Operator(ref c) if **c == "=>", "Expected '=>'");
|
||
let expr = self.expression()?;
|
||
arms.push(MatchArm {pat, expr});
|
||
match self.peek() {
|
||
Comma => { self.next(); },
|
||
_ => break
|
||
}
|
||
}
|
||
Ok(arms)
|
||
});
|
||
|
||
parse_method!(pattern(&mut self) -> ParseResult<Pattern> {
|
||
let identifier = self.identifier()?;
|
||
Ok(Pattern(identifier))
|
||
});
|
||
|
||
parse_method!(identifier(&mut self) -> ParseResult<Rc<String>> {
|
||
match self.next() {
|
||
Identifier(s) => Ok(s),
|
||
p => ParseError::new(&format!("Expected an identifier, got {:?}", p)),
|
||
}
|
||
});
|
||
|
||
parse_method!(literal(&mut self) -> ParseResult<Expression> {
|
||
match self.peek() {
|
||
DigitGroup(_) | HexNumberSigil | BinNumberSigil | Period => self.number_literal(),
|
||
Keyword(Kw::True) => { self.next(); Ok(Expression::BoolLiteral(true)) },
|
||
Keyword(Kw::False) => { self.next(); Ok(Expression::BoolLiteral(false)) },
|
||
StrLiteral(s) => {
|
||
self.next();
|
||
Ok(Expression::StringLiteral(s))
|
||
}
|
||
e => ParseError::new(&format!("Expected a literal expression, got {:?}", e)),
|
||
}
|
||
});
|
||
|
||
parse_method!(number_literal(&mut self) -> ParseResult<Expression> {
|
||
match self.peek() {
|
||
HexNumberSigil | BinNumberSigil => self.int_literal(),
|
||
_ => self.float_literal(),
|
||
}
|
||
});
|
||
|
||
parse_method!(int_literal(&mut self) -> ParseResult<Expression> {
|
||
use self::Expression::*;
|
||
match self.next() {
|
||
BinNumberSigil => {
|
||
let digits = self.digits()?;
|
||
let n = parse_binary(digits)?;
|
||
Ok(IntLiteral(n))
|
||
},
|
||
HexNumberSigil => {
|
||
ParseError::new("Not implemented")
|
||
},
|
||
_ => return ParseError::new("Expected '0x' or '0b'"),
|
||
}
|
||
});
|
||
|
||
parse_method!(float_literal(&mut self) -> ParseResult<Expression> {
|
||
use self::Expression::*;
|
||
let mut digits = self.digits()?;
|
||
if let TokenType::Period = self.peek() {
|
||
self.next();
|
||
digits.push_str(".");
|
||
digits.push_str(&self.digits()?);
|
||
match digits.parse::<f64>() {
|
||
Ok(f) => Ok(FloatLiteral(f)),
|
||
Err(e) => ParseError::new(&format!("Float failed to parse with error: {}", e)),
|
||
|
||
}
|
||
} else {
|
||
match digits.parse::<u64>() {
|
||
Ok(d) => Ok(IntLiteral(d)),
|
||
Err(e) => ParseError::new(&format!("Integer failed to parse with error: {}", e)),
|
||
}
|
||
}
|
||
});
|
||
|
||
parse_method!(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>, Vec<String>) {
|
||
let mut parser = Parser::new(input);
|
||
let ast = parser.program();
|
||
|
||
let trace = parser.parse_record.into_iter().map(|r| {
|
||
format!("Production `{}`, token: {:?}", r.production_name, r.next_token)
|
||
}).collect();
|
||
(ast, trace)
|
||
}
|
||
|
||
#[cfg(test)]
|
||
mod parse_tests {
|
||
use super::*;
|
||
use super::Statement::*;
|
||
use super::Declaration::*;
|
||
use super::Expression::*;
|
||
|
||
macro_rules! rc {
|
||
($string:tt) => { Rc::new(stringify!($string).to_string()) }
|
||
}
|
||
|
||
macro_rules! parse_test {
|
||
($string:expr, $correct:expr) => { assert_eq!(parse(tokenize($string)).0.unwrap(), $correct) }
|
||
}
|
||
|
||
macro_rules! binexp {
|
||
($op:expr, $lhs:expr, $rhs:expr) => { BinExp(op!($op), Box::new($lhs), Box::new($rhs)) }
|
||
}
|
||
macro_rules! prefexp {
|
||
($op:expr, $lhs:expr) => { PrefixExp(op!($op), Box::new($lhs)) }
|
||
}
|
||
macro_rules! op {
|
||
($op:expr) => { Operation(Rc::new($op.to_string())) }
|
||
}
|
||
macro_rules! var {
|
||
($var:expr) => { Variable(Rc::new($var.to_string())) }
|
||
}
|
||
|
||
#[test]
|
||
fn parsing_number_literals_and_binexps() {
|
||
parse_test!(".2", AST(vec![Expression(FloatLiteral(0.2))]));
|
||
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!("+", IntLiteral(1), binexp!("*", IntLiteral(2), IntLiteral(3))))
|
||
]));
|
||
|
||
parse_test!("1 * 2 + 3", AST(vec!
|
||
[
|
||
Expression(binexp!("+", binexp!("*", IntLiteral(1), IntLiteral(2)), IntLiteral(3)))
|
||
]));
|
||
|
||
parse_test!("1 && 2", AST(vec![Expression(binexp!("&&", IntLiteral(1), IntLiteral(2)))]));
|
||
|
||
parse_test!("1 + 2 * 3 + 4", AST(vec![Expression(
|
||
binexp!("+",
|
||
binexp!("+", IntLiteral(1),
|
||
binexp!("*", IntLiteral(2), IntLiteral(3))
|
||
),
|
||
IntLiteral(4)
|
||
)
|
||
)]));
|
||
|
||
parse_test!("(1 + 2) * 3", AST(vec!
|
||
[
|
||
Expression(binexp!("*", binexp!("+", IntLiteral(1), IntLiteral(2)), IntLiteral(3)))
|
||
]));
|
||
|
||
parse_test!(".1 + .2", AST(vec![Expression(binexp!("+", FloatLiteral(0.1), FloatLiteral(0.2)))]));
|
||
}
|
||
|
||
#[test]
|
||
fn parsing_identifiers() {
|
||
parse_test!("a", AST(vec![Expression(var!("a"))]));
|
||
parse_test!("a + b", AST(vec![Expression(binexp!("+", var!("a"), var!("b")))]));
|
||
//parse_test!("a[b]", AST(vec![Expression(
|
||
//parse_test!("a[]", <- TODO THIS NEEDS TO FAIL
|
||
//parse_test!(damn()[a] ,<- TODO needs to succeed
|
||
parse_test!("a[b,c]", AST(vec![Expression(Index { indexee: Box::new(var!("a")), indexers: vec![var!("b"), var!("c")]} )]));
|
||
}
|
||
|
||
#[test]
|
||
fn parsing_complicated_operators() {
|
||
parse_test!("a <- b", AST(vec![Expression(binexp!("<-", var!("a"), var!("b")))]));
|
||
parse_test!("a || b", AST(vec![Expression(binexp!("||", var!("a"), var!("b")))]));
|
||
parse_test!("a<>b", AST(vec![Expression(binexp!("<>", var!("a"), var!("b")))]));
|
||
parse_test!("a.b.c.d", AST(vec![Expression(binexp!(".",
|
||
binexp!(".",
|
||
binexp!(".", var!("a"), var!("b")),
|
||
var!("c")),
|
||
var!("d")))]));
|
||
parse_test!("-3", AST(vec![Expression(prefexp!("-", IntLiteral(3)))]));
|
||
parse_test!("-0.2", AST(vec![Expression(prefexp!("-", FloatLiteral(0.2)))]));
|
||
parse_test!("!3", AST(vec![Expression(prefexp!("!", IntLiteral(3)))]));
|
||
parse_test!("a <- -b", AST(vec![Expression(binexp!("<-", var!("a"), prefexp!("-", var!("b"))))]));
|
||
parse_test!("a <--b", AST(vec![Expression(binexp!("<--", var!("a"), var!("b")))]));
|
||
}
|
||
|
||
#[test]
|
||
fn parsing_functions() {
|
||
parse_test!("fn oi()", AST(vec![Declaration(FuncDecl { name: rc!(oi), params: vec![] })]));
|
||
parse_test!("oi()", AST(vec![Expression(Call { name: rc!(oi), params: vec![] })]));
|
||
parse_test!("oi(a, 2 + 2)", AST(vec![Expression(Call
|
||
{ name: rc!(oi),
|
||
params: vec![var!("a"), binexp!("+", IntLiteral(2), IntLiteral(2))]
|
||
})]));
|
||
}
|
||
|
||
#[test]
|
||
fn parsing_bools() {
|
||
parse_test!("false", AST(vec![Expression(BoolLiteral(false))]));
|
||
parse_test!("true", AST(vec![Expression(BoolLiteral(true))]));
|
||
}
|
||
|
||
#[test]
|
||
fn parsing_strings() {
|
||
parse_test!(r#""hello""#, AST(vec![Expression(StringLiteral(rc!(hello)))]));
|
||
}
|
||
|
||
#[test]
|
||
fn parsing_types() {
|
||
parse_test!("type Yolo = Yolo", AST(vec![Declaration(TypeDecl(rc!(Yolo), TypeBody(vec![Variant::Singleton(rc!(Yolo))])))]));
|
||
parse_test!("alias Sex = Drugs", AST(vec![Declaration(TypeAlias(rc!(Sex), rc!(Drugs)))]));
|
||
}
|
||
|
||
#[test]
|
||
fn parsing_bindings() {
|
||
parse_test!("var a = 10", AST(vec![Declaration(Binding { name: rc!(a), constant: false, expr: IntLiteral(10) } )]));
|
||
parse_test!("const a = 2 + 2", AST(vec![Declaration(Binding { name: rc!(a), constant: true, expr: binexp!("+", IntLiteral(2), IntLiteral(2)) }) ]));
|
||
}
|
||
|
||
#[test]
|
||
fn parsing_block_expressions() {
|
||
parse_test!("if a() { b(); c() }", AST(vec![Expression(
|
||
IfExpression(Box::new(Call { name: rc!(a), params: vec![]}),
|
||
vec![Expression(Call { name: rc!(b), params: vec![]}), Expression(Call { name: rc!(c), params: vec![] })],
|
||
None))]));
|
||
parse_test!(r#"
|
||
if true {
|
||
const a = 10
|
||
b
|
||
} else {
|
||
c
|
||
}"#,
|
||
AST(vec![Expression(IfExpression(Box::new(BoolLiteral(true)),
|
||
vec![Declaration(Binding { name: rc!(a), constant: true, expr: IntLiteral(10) }),
|
||
Expression(Variable(rc!(b)))],
|
||
Some(vec![Expression(Variable(rc!(c)))])))])
|
||
);
|
||
}
|
||
}
|