schala/src/schala_lang/tokenizing.rs
2018-02-23 01:59:53 -08:00

244 lines
6.4 KiB
Rust

use itertools::Itertools;
use std::collections::HashMap;
use std::rc::Rc;
use std::iter::{Enumerate, Peekable};
use std::str::Chars;
#[derive(Debug, PartialEq, Clone)]
pub enum TokenType {
Newline, Semicolon,
LParen, RParen,
LSquareBracket, RSquareBracket,
LAngleBracket, RAngleBracket,
LCurlyBrace, RCurlyBrace,
Pipe,
Comma, Period, Colon, Underscore,
Operator(Rc<String>),
DigitGroup(Rc<String>), HexLiteral(Rc<String>), BinNumberSigil,
StrLiteral(Rc<String>),
Identifier(Rc<String>),
Keyword(Kw),
EOF,
Error(String),
}
use self::TokenType::*;
#[derive(Debug, Clone, Copy, PartialEq)]
pub enum Kw {
If, Else,
Func,
For,
Match,
Var, Const, Let, In,
Return,
Alias, Type, SelfType, SelfIdent,
Trait, Impl,
True, False,
Module
}
lazy_static! {
static ref KEYWORDS: HashMap<&'static str, Kw> =
hashmap! {
"if" => Kw::If,
"else" => Kw::Else,
"fn" => Kw::Func,
"for" => Kw::For,
"match" => Kw::Match,
"var" => Kw::Var,
"const" => Kw::Const,
"let" => Kw::Let,
"in" => Kw::In,
"return" => Kw::Return,
"alias" => Kw::Alias,
"type" => Kw::Type,
"Self" => Kw::SelfType,
"self" => Kw::SelfIdent,
"trait" => Kw::Trait,
"impl" => Kw::Impl,
"true" => Kw::True,
"false" => Kw::False,
"module" => Kw::Module,
};
}
#[derive(Debug)]
pub struct Token {
pub token_type: TokenType,
pub offset: usize,
}
impl Token {
pub fn get_error(&self) -> Option<&String> {
match self.token_type {
TokenType::Error(ref s) => Some(s),
_ => None,
}
}
}
const OPERATOR_CHARS: [char; 19] = ['!', '$', '%', '&', '*', '+', '-', '.', '/', ':', '<', '>', '=', '?', '@', '^', '|', '~', '`'];
fn is_operator(c: &char) -> bool {
OPERATOR_CHARS.iter().any(|x| x == c)
}
type CharIter<'a> = Peekable<Enumerate<Chars<'a>>>;
pub fn tokenize(input: &str) -> Vec<Token> {
let mut tokens: Vec<Token> = Vec::new();
let mut input: CharIter = input.chars().enumerate().peekable();
while let Some((idx, c)) = input.next() {
let cur_tok_type = match c {
'#' => {
if let Some(&(_, '{')) = input.peek() {
} else {
while let Some((_, c)) = input.next() {
if c == '\n' {
break;
}
}
}
continue;
},
c if c.is_whitespace() && c != '\n' => continue,
'\n' => Newline, ';' => Semicolon,
':' => Colon, ',' => Comma,
'(' => LParen, ')' => RParen,
'{' => LCurlyBrace, '}' => RCurlyBrace,
'[' => LSquareBracket, ']' => RSquareBracket,
'"' => handle_quote(&mut input),
c if c.is_digit(10) => handle_digit(c, &mut input),
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
c if is_operator(&c) => handle_operator(c, &mut input),
unknown => Error(format!("Unexpected character: {}", unknown)),
};
tokens.push(Token { token_type: cur_tok_type, offset: idx });
}
tokens
}
fn handle_digit(c: char, input: &mut CharIter) -> TokenType {
if c == '0' && input.peek().map_or(false, |&(_, c)| { c == 'x' }) {
input.next();
let rest: String = input.peeking_take_while(|&(_, ref c)| c.is_digit(16) || *c == '_').map(|(_, c)| { c }).collect();
HexLiteral(Rc::new(rest))
} else if c == '0' && input.peek().map_or(false, |&(_, c)| { c == 'b' }) {
input.next();
BinNumberSigil
} else {
let mut buf = c.to_string();
buf.extend(input.peeking_take_while(|&(_, ref c)| c.is_digit(10)).map(|(_, c)| { c }));
DigitGroup(Rc::new(buf))
}
}
fn handle_quote(input: &mut CharIter) -> TokenType {
let mut buf = String::new();
loop {
match input.next().map(|(_, c)| { c }) {
Some('"') => break,
Some('\\') => {
let next = input.peek().map(|&(_, c)| { c });
if next == Some('n') {
input.next();
buf.push('\n')
} else if next == Some('"') {
input.next();
buf.push('"');
} else if next == Some('t') {
input.next();
buf.push('\t');
}
},
Some(c) => buf.push(c),
None => return TokenType::Error(format!("Unclosed string")),
}
}
TokenType::StrLiteral(Rc::new(buf))
}
fn handle_alphabetic(c: char, input: &mut CharIter) -> TokenType {
let mut buf = String::new();
buf.push(c);
if c == '_' && input.peek().map(|&(_, c)| { !c.is_alphabetic() }).unwrap_or(true) {
return TokenType::Underscore
}
loop {
match input.peek().map(|&(_, c)| { c }) {
Some(c) if c.is_alphanumeric() => {
input.next();
buf.push(c);
},
_ => break,
}
}
match KEYWORDS.get(buf.as_str()) {
Some(kw) => TokenType::Keyword(*kw),
None => TokenType::Identifier(Rc::new(buf)),
}
}
fn handle_operator(c: char, input: &mut CharIter) -> TokenType {
match c {
'<' | '>' | '|' | '.' => {
let ref next = input.peek().map(|&(_, c)| { c });
if !next.map(|n| { is_operator(&n) }).unwrap_or(false) {
return match c {
'<' => LAngleBracket,
'>' => RAngleBracket,
'|' => Pipe,
'.' => Period,
_ => unreachable!(),
}
}
},
_ => (),
};
let mut buf = String::new();
buf.push(c);
loop {
match input.peek().map(|&(_, c)| { c }) {
Some(c) if is_operator(&c) => {
input.next();
buf.push(c);
},
_ => break
}
}
TokenType::Operator(Rc::new(buf))
}
#[cfg(test)]
mod schala_tokenizer_tests {
use super::*;
use super::Kw::*;
macro_rules! digit { ($ident:expr) => { DigitGroup(Rc::new($ident.to_string())) } }
macro_rules! ident { ($ident:expr) => { Identifier(Rc::new($ident.to_string())) } }
macro_rules! op { ($ident:expr) => { Operator(Rc::new($ident.to_string())) } }
#[test]
fn tokens() {
let a = tokenize("let a: A<B> = c ++ d");
let token_types: Vec<TokenType> = a.into_iter().map(move |t| t.token_type).collect();
assert_eq!(token_types, vec![Keyword(Let), ident!("a"), Colon, ident!("A"),
LAngleBracket, ident!("B"), RAngleBracket, op!("="), ident!("c"), op!("++"), ident!("d")]);
}
#[test]
fn underscores() {
let token_types: Vec<TokenType> = tokenize("4_8").into_iter().map(move |t| t.token_type).collect();
assert_eq!(token_types, vec![digit!("4"), Underscore, digit!("8")]);
}
}