schala/schala-lang/language/src/tokenizing.rs
2021-10-19 16:45:04 -07:00

372 lines
10 KiB
Rust

use itertools::Itertools;
use std::{iter::{Iterator, Peekable}, convert::TryFrom, rc::Rc, fmt};
use std::convert::TryInto;
/// A location in a particular source file. Note that the
/// sizes of the internal unsigned integer types limit
/// the size of a source file to 2^32 lines of
/// at most 2^16 characters, which should be plenty big.
#[derive(Debug, Clone, Copy, PartialEq, Default)]
pub struct Location {
pub(crate) line_num: u32,
pub(crate) char_num: u16,
}
impl fmt::Display for Location {
fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
write!(f, "{}:{}", self.line_num, self.char_num)
}
}
#[derive(Debug, PartialEq, Clone)]
pub enum TokenKind {
Newline, Semicolon,
LParen, RParen,
LSquareBracket, RSquareBracket,
LAngleBracket, RAngleBracket,
LCurlyBrace, RCurlyBrace,
Pipe, Backslash,
Comma, Period, Colon, Underscore,
Slash, Equals,
Operator(Rc<String>),
DigitGroup(Rc<String>), HexLiteral(Rc<String>), BinNumberSigil,
StrLiteral {
s: Rc<String>,
prefix: Option<Rc<String>>
},
Identifier(Rc<String>),
Keyword(Kw),
EOF,
Error(String),
}
use self::TokenKind::*;
impl fmt::Display for TokenKind {
fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
match self {
&Operator(ref s) => write!(f, "Operator({})", **s),
&DigitGroup(ref s) => write!(f, "DigitGroup({})", s),
&HexLiteral(ref s) => write!(f, "HexLiteral({})", s),
&StrLiteral {ref s, .. } => write!(f, "StrLiteral({})", s),
&Identifier(ref s) => write!(f, "Identifier({})", s),
&Error(ref s) => write!(f, "Error({})", s),
other => write!(f, "{:?}", other),
}
}
}
#[derive(Debug, Clone, Copy, PartialEq)]
pub enum Kw {
If, Then, Else,
Is,
Func,
For, While,
Const, Let, In,
Mut,
Return,
Alias, Type, SelfType, SelfIdent,
Interface, Impl,
True, False,
Module, Import
}
impl TryFrom<&str> for Kw {
type Error = ();
fn try_from(value: &str) -> Result<Self, Self::Error> {
Ok(match value {
"if" => Kw::If,
"then" => Kw::Then,
"else" => Kw::Else,
"is" => Kw::Is,
"fn" => Kw::Func,
"for" => Kw::For,
"while" => Kw::While,
"const" => Kw::Const,
"let" => Kw::Let,
"in" => Kw::In,
"mut" => Kw::Mut,
"return" => Kw::Return,
"alias" => Kw::Alias,
"type" => Kw::Type,
"Self" => Kw::SelfType,
"self" => Kw::SelfIdent,
"interface" => Kw::Interface,
"impl" => Kw::Impl,
"true" => Kw::True,
"false" => Kw::False,
"module" => Kw::Module,
"import" => Kw::Import,
_ => return Err(()),
})
}
}
#[derive(Debug, Clone, PartialEq)]
pub struct Token {
pub kind: TokenKind,
pub(crate) location: Location,
}
impl Token {
pub fn to_string_with_metadata(&self) -> String {
format!("{}({})", self.kind, self.location)
}
pub fn get_kind(&self) -> TokenKind {
self.kind.clone()
}
}
const OPERATOR_CHARS: [char; 18] = ['!', '$', '%', '&', '*', '+', '-', '.', ':', '<', '>', '=', '?', '@', '^', '|', '~', '`'];
fn is_operator(c: &char) -> bool {
OPERATOR_CHARS.iter().any(|x| x == c)
}
type CharData = (usize, usize, char);
pub fn tokenize(input: &str) -> Vec<Token> {
let mut tokens: Vec<Token> = Vec::new();
let mut input = Iterator::intersperse(input.lines().enumerate(), (0, "\n"))
.flat_map(|(line_idx, ref line)| {
line.chars().enumerate().map(move |(ch_idx, ch)| (line_idx, ch_idx, ch))
})
.peekable();
while let Some((line_num, char_num, c)) = input.next() {
let cur_tok_kind = match c {
'/' => match input.peek().map(|t| t.2) {
Some('/') => {
while let Some((_, _, c)) = input.next() {
if c == '\n' {
break;
}
}
continue;
},
Some('*') => {
input.next();
let mut comment_level = 1;
while let Some((_, _, c)) = input.next() {
if c == '*' && input.peek().map(|t| t.2) == Some('/') {
input.next();
comment_level -= 1;
} else if c == '/' && input.peek().map(|t| t.2) == Some('*') {
input.next();
comment_level += 1;
}
if comment_level == 0 {
break;
}
}
if comment_level != 0 {
Error("Unclosed comment".to_string())
} else {
continue;
}
},
_ => Slash
},
c if c.is_whitespace() && c != '\n' => continue,
'\n' => Newline, ';' => Semicolon,
':' => Colon, ',' => Comma,
'(' => LParen, ')' => RParen,
'{' => LCurlyBrace, '}' => RCurlyBrace,
'[' => LSquareBracket, ']' => RSquareBracket,
'"' => handle_quote(&mut input, None),
'\\' => Backslash,
c if c.is_digit(10) => handle_digit(c, &mut input),
c if c.is_alphabetic() || c == '_' => handle_alphabetic(c, &mut input),
c if is_operator(&c) => handle_operator(c, &mut input),
unknown => Error(format!("Unexpected character: {}", unknown)),
};
let location = Location { line_num: line_num.try_into().unwrap(), char_num: char_num.try_into().unwrap() };
tokens.push(Token { kind: cur_tok_kind, location });
}
tokens
}
fn handle_digit(c: char, input: &mut Peekable<impl Iterator<Item=CharData>>) -> TokenKind {
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 Peekable<impl Iterator<Item=CharData>>, quote_prefix: Option<&str>) -> TokenKind {
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 TokenKind::Error("Unclosed string".to_string()),
}
}
TokenKind::StrLiteral { s: Rc::new(buf), prefix: quote_prefix.map(|s| Rc::new(s.to_string())) }
}
fn handle_alphabetic(c: char, input: &mut Peekable<impl Iterator<Item=CharData>>) -> TokenKind {
let mut buf = String::new();
buf.push(c);
if c == '_' && input.peek().map(|&(_, _, c)| { !c.is_alphabetic() }).unwrap_or(true) {
return TokenKind::Underscore
}
loop {
match input.peek().map(|&(_, _, c)| { c }) {
Some(c) if c == '"' => {
input.next();
return handle_quote(input, Some(&buf));
},
Some(c) if c.is_alphanumeric() || c == '_' => {
input.next();
buf.push(c);
},
_ => break,
}
}
match Kw::try_from(buf.as_str()) {
Ok(kw) => TokenKind::Keyword(kw),
Err(()) => TokenKind::Identifier(Rc::new(buf)),
}
}
fn handle_operator(c: char, input: &mut Peekable<impl Iterator<Item=CharData>>) -> TokenKind {
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,
'=' => Equals,
_ => unreachable!(),
}
}
},
_ => (),
};
let mut buf = String::new();
if c == '`' {
loop {
match input.peek().map(|&(_, _, c)| { c }) {
Some(c) if c.is_alphabetic() || c == '_' => {
input.next();
buf.push(c);
},
Some('`') => {
input.next();
break;
},
_ => break
}
}
} else {
buf.push(c);
loop {
match input.peek().map(|&(_, _, c)| { c }) {
Some(c) if is_operator(&c) => {
input.next();
buf.push(c);
},
_ => break
}
}
}
TokenKind::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())) } }
fn token_kinds(input: &str) -> Vec<TokenKind> {
tokenize(input).into_iter().map(move |tok| tok.kind).collect()
}
#[test]
fn tokens() {
let output = token_kinds("let a: A<B> = c ++ d");
assert_eq!(output, vec![Keyword(Let), ident!("a"), Colon, ident!("A"),
LAngleBracket, ident!("B"), RAngleBracket, Equals, ident!("c"), op!("++"), ident!("d")]);
}
#[test]
fn underscores() {
let output = token_kinds("4_8");
assert_eq!(output, vec![digit!("4"), Underscore, digit!("8")]);
let output = token_kinds("aba_yo");
assert_eq!(output, vec![ident!("aba_yo")]);
}
#[test]
fn comments() {
let output = token_kinds("1 + /* hella /* bro */ */ 2");
assert_eq!(output, vec![digit!("1"), op!("+"), digit!("2")]);
let output = token_kinds("1 + /* hella /* bro */ 2");
assert_eq!(output, vec![digit!("1"), op!("+"), Error("Unclosed comment".to_string())]);
//TODO not sure if I want this behavior
let output = token_kinds("1 + /* hella */ bro */ 2");
assert_eq!(output, vec![digit!("1"), op!("+"), Identifier(Rc::new("bro".to_string())), Operator(Rc::new("*".to_string())), Slash, DigitGroup(Rc::new("2".to_string()))]);
}
#[test]
fn backtick_operators() {
let output = token_kinds("1 `plus` 2");
assert_eq!(output, vec![digit!("1"), op!("plus"), digit!("2")]);
}
#[test]
fn string_literals() {
let output = token_kinds(r#""some string""#);
assert_eq!(output, vec![StrLiteral { s: Rc::new("some string".to_string()), prefix: None }]);
let output = token_kinds(r#"b"some bytestring""#);
assert_eq!(output, vec![StrLiteral { s: Rc::new("some bytestring".to_string()), prefix: Some(Rc::new("b".to_string())) }]);
let output = token_kinds(r#""Do \n \" escapes work\t""#);
assert_eq!(output, vec![StrLiteral { s: Rc::new("Do \n \" escapes work\t".to_string()), prefix: None }]);
}
}