mirror of
https://github.com/typst/typst
synced 2025-05-14 04:56:26 +08:00
482 lines
17 KiB
Rust
482 lines
17 KiB
Rust
//! Tokenization.
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use std::fmt::{self, Debug, Formatter};
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use super::{is_newline, Scanner};
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use crate::length::Length;
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use crate::syntax::token::*;
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use crate::syntax::{is_ident, Pos};
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use TokenMode::*;
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/// An iterator over the tokens of a string of source code.
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#[derive(Clone)]
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pub struct Tokens<'s> {
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s: Scanner<'s>,
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mode: TokenMode,
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}
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/// Whether to tokenize in header mode which yields expression, comma and
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/// similar tokens or in body mode which yields text and star, underscore,
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/// backtick tokens.
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#[derive(Debug, Copy, Clone, Eq, PartialEq)]
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pub enum TokenMode {
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Header,
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Body,
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}
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impl<'s> Tokens<'s> {
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/// Create a new token iterator with the given mode.
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pub fn new(src: &'s str, mode: TokenMode) -> Self {
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Self { s: Scanner::new(src), mode }
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}
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/// Get the current token mode.
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pub fn mode(&self) -> TokenMode {
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self.mode
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}
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/// Change the token mode.
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pub fn set_mode(&mut self, mode: TokenMode) {
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self.mode = mode;
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}
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/// The position in the string at which the last token ends and next token
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/// will start.
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pub fn pos(&self) -> Pos {
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self.s.index().into()
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}
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/// Jump to a position in the source string.
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pub fn jump(&mut self, pos: Pos) {
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self.s.jump(pos.to_usize());
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}
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/// The underlying scanner.
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pub fn scanner(&self) -> &Scanner<'s> {
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&self.s
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}
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}
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impl<'s> Iterator for Tokens<'s> {
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type Item = Token<'s>;
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/// Parse the next token in the source code.
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fn next(&mut self) -> Option<Self::Item> {
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let start = self.s.index();
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Some(match self.s.eat()? {
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// Whitespace with fast path for just a single space.
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' ' if !self.s.check(|c| c.is_whitespace()) => Token::Space(0),
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c if c.is_whitespace() => {
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self.s.jump(start);
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self.read_whitespace()
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}
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// Comments.
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'/' if self.s.eat_if('/') => self.read_line_comment(),
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'/' if self.s.eat_if('*') => self.read_block_comment(),
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'*' if self.s.eat_if('/') => Token::Invalid("*/"),
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// Functions.
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'[' => Token::LeftBracket,
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']' => Token::RightBracket,
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'{' => Token::LeftBrace,
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'}' => Token::RightBrace,
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// Syntactic elements in body text.
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'*' if self.mode == Body => Token::Star,
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'_' if self.mode == Body => Token::Underscore,
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'#' if self.mode == Body => Token::Hashtag,
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'~' if self.mode == Body => Token::NonBreakingSpace,
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'`' if self.mode == Body => self.read_raw(),
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'\\' if self.mode == Body => self.read_escaped(),
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// Syntactic elements in headers.
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'(' if self.mode == Header => Token::LeftParen,
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')' if self.mode == Header => Token::RightParen,
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':' if self.mode == Header => Token::Colon,
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',' if self.mode == Header => Token::Comma,
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'=' if self.mode == Header => Token::Equals,
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'>' if self.mode == Header && self.s.eat_if('>') => Token::Chain,
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'+' if self.mode == Header => Token::Plus,
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'-' if self.mode == Header => Token::Hyphen,
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'*' if self.mode == Header => Token::Star,
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'/' if self.mode == Header => Token::Slash,
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// Expressions in headers.
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'#' if self.mode == Header => self.read_hex(),
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'"' if self.mode == Header => self.read_string(),
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// Expressions or just plain text.
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_ => self.read_text_or_expr(start),
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})
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}
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}
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impl<'s> Tokens<'s> {
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fn read_whitespace(&mut self) -> Token<'s> {
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// Count the number of newlines.
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let mut newlines = 0;
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while let Some(c) = self.s.eat_merging_crlf() {
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if !c.is_whitespace() {
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self.s.uneat();
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break;
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}
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if is_newline(c) {
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newlines += 1;
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}
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}
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Token::Space(newlines)
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}
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fn read_line_comment(&mut self) -> Token<'s> {
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Token::LineComment(self.s.eat_until(is_newline))
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}
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fn read_block_comment(&mut self) -> Token<'s> {
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let start = self.s.index();
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let mut state = '_';
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let mut depth = 1;
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// Find the first `*/` that does not correspond to a nested `/*`.
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while let Some(c) = self.s.eat() {
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state = match (state, c) {
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('*', '/') => {
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depth -= 1;
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if depth == 0 {
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break;
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}
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'_'
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}
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('/', '*') => {
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depth += 1;
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'_'
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}
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_ => c,
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}
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}
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let terminated = depth == 0;
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let end = self.s.index() - if terminated { 2 } else { 0 };
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Token::BlockComment(self.s.get(start .. end))
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}
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fn read_raw(&mut self) -> Token<'s> {
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let mut backticks = 1;
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while self.s.eat_if('`') {
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backticks += 1;
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}
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let start = self.s.index();
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let mut found = 0;
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while found < backticks {
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match self.s.eat() {
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Some('`') => found += 1,
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Some(_) => found = 0,
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None => break,
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}
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}
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let terminated = found == backticks;
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let end = self.s.index() - if terminated { found } else { 0 };
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Token::Raw(TokenRaw {
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text: self.s.get(start .. end),
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backticks,
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terminated,
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})
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}
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fn read_escaped(&mut self) -> Token<'s> {
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if let Some(c) = self.s.peek() {
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match c {
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'[' | ']' | '\\' | '/' | '*' | '_' | '`' | '"' | '#' | '~' => {
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let start = self.s.index();
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self.s.eat_assert(c);
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Token::Text(&self.s.eaten_from(start))
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}
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'u' if self.s.peek_nth(1) == Some('{') => {
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self.s.eat_assert('u');
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self.s.eat_assert('{');
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Token::UnicodeEscape(TokenUnicodeEscape {
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sequence: self.s.eat_while(|c| c.is_ascii_hexdigit()),
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terminated: self.s.eat_if('}'),
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})
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}
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c if c.is_whitespace() => Token::Backslash,
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_ => Token::Text("\\"),
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}
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} else {
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Token::Backslash
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}
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}
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fn read_hex(&mut self) -> Token<'s> {
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// This parses more than the permissable 0-9, a-f, A-F character ranges
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// to provide nicer error messages later.
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Token::Hex(self.s.eat_while(|c| c.is_ascii_alphanumeric()))
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}
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fn read_string(&mut self) -> Token<'s> {
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let mut escaped = false;
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Token::Str(TokenStr {
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string: self.s.eat_until(|c| {
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if c == '"' && !escaped {
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true
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} else {
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escaped = c == '\\' && !escaped;
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false
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}
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}),
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terminated: self.s.eat_if('"'),
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})
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}
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fn read_text_or_expr(&mut self, start: usize) -> Token<'s> {
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let body = self.mode == Body;
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let header = self.mode == Header;
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let mut last_was_e = false;
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self.s.eat_until(|c| {
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let end = match c {
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c if c.is_whitespace() => true,
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'[' | ']' | '{' | '}' | '*' | '/' | '#' => true,
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'_' | '`' | '~' | '\\' if body => true,
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'(' | ')' | ':' | ',' | '=' | '"' if header => true,
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'+' | '-' if header && !last_was_e => true,
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_ => false,
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};
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last_was_e = c == 'e' || c == 'E';
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end
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});
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let read = self.s.eaten_from(start);
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if self.mode == Header {
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parse_expr(read)
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} else {
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Token::Text(read)
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}
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}
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}
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impl Debug for Tokens<'_> {
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fn fmt(&self, f: &mut Formatter) -> fmt::Result {
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write!(f, "Tokens({}|{})", self.s.eaten(), self.s.rest())
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}
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}
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fn parse_expr(text: &str) -> Token<'_> {
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if let Ok(b) = text.parse::<bool>() {
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Token::Bool(b)
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} else if let Ok(int) = text.parse::<i64>() {
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Token::Int(int)
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} else if let Ok(num) = text.parse::<f64>() {
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Token::Float(num)
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} else if let Some(percent) = parse_percent(text) {
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Token::Percent(percent)
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} else if let Ok(length) = text.parse::<Length>() {
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Token::Length(length)
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} else if is_ident(text) {
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Token::Ident(text)
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} else {
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Token::Invalid(text)
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}
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}
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fn parse_percent(text: &str) -> Option<f64> {
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text.strip_suffix('%').and_then(|num| num.parse::<f64>().ok())
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}
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#[cfg(test)]
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#[allow(non_snake_case)]
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mod tests {
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use super::*;
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use crate::length::Length;
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use crate::parse::tests::check;
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use Token::{
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BlockComment as BC, Bool, Chain, Float, Hex, Hyphen as Min, Ident as Id, Int,
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LeftBrace as LB, LeftBracket as L, LeftParen as LP, Length as Len,
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LineComment as LC, NonBreakingSpace as Nbsp, Percent, Plus, RightBrace as RB,
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RightBracket as R, RightParen as RP, Slash, Space as S, Star, Text as T, *,
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};
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fn Str(string: &str, terminated: bool) -> Token {
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Token::Str(TokenStr { string, terminated })
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}
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fn Raw(text: &str, backticks: usize, terminated: bool) -> Token {
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Token::Raw(TokenRaw { text, backticks, terminated })
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}
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fn UE(sequence: &str, terminated: bool) -> Token {
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Token::UnicodeEscape(TokenUnicodeEscape { sequence, terminated })
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}
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macro_rules! t {
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($mode:expr, $src:expr => $($token:expr),*) => {
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let exp = vec![$($token),*];
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let found = Tokens::new($src, $mode).collect::<Vec<_>>();
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check($src, exp, found, false);
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}
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}
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#[test]
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fn tokenize_whitespace() {
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t!(Body, "" => );
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t!(Body, " " => S(0));
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t!(Body, " " => S(0));
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t!(Body, "\t" => S(0));
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t!(Body, " \t" => S(0));
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t!(Body, "\n" => S(1));
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t!(Body, "\n " => S(1));
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t!(Body, " \n" => S(1));
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t!(Body, " \n " => S(1));
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t!(Body, "\r\n" => S(1));
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t!(Body, " \n\t \n " => S(2));
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t!(Body, "\n\r" => S(2));
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t!(Body, " \r\r\n \x0D" => S(3));
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t!(Body, "a~b" => T("a"), Nbsp, T("b"));
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}
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#[test]
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fn tokenize_comments() {
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t!(Body, "a // bc\n " => T("a"), S(0), LC(" bc"), S(1));
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t!(Body, "a //a//b\n " => T("a"), S(0), LC("a//b"), S(1));
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t!(Body, "a //a//b\r\n" => T("a"), S(0), LC("a//b"), S(1));
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t!(Body, "a //a//b\n\nhello" => T("a"), S(0), LC("a//b"), S(2), T("hello"));
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t!(Body, "/**/" => BC(""));
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t!(Body, "_/*_/*a*/*/" => Underscore, BC("_/*a*/"));
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t!(Body, "/*/*/" => BC("/*/"));
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t!(Body, "abc*/" => T("abc"), Invalid("*/"));
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t!(Body, "/***/" => BC("*"));
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t!(Body, "/**\\****/*/*/" => BC("*\\***"), Invalid("*/"), Invalid("*/"));
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t!(Body, "/*abc" => BC("abc"));
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t!(Body, "/*/*abc*/" => BC("/*abc*/"));
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}
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#[test]
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fn tokenize_body_tokens() {
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t!(Body, "a_*" => T("a"), Underscore, Star);
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t!(Body, "a***" => T("a"), Star, Star, Star);
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t!(Body, "[func]*bold*" => L, T("func"), R, Star, T("bold"), Star);
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t!(Body, "hi_you_ there" => T("hi"), Underscore, T("you"), Underscore, S(0), T("there"));
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t!(Body, "# hi" => Hashtag, S(0), T("hi"));
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t!(Body, "ab# hi" => T("ab"), Hashtag, S(0), T("hi"));
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t!(Body, "#{}" => Hashtag, LB, RB);
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t!(Body, "{text}" => LB, Text("text"), RB);
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t!(Header, "_`" => Invalid("_`"));
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}
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#[test]
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fn test_tokenize_raw() {
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// Basics.
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t!(Body, "a`raw`" => T("a"), Raw("raw", 1, true));
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t!(Body, "`[func]`" => Raw("[func]", 1, true));
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t!(Body, "`]" => Raw("]", 1, false));
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t!(Body, r"`\`` " => Raw(r"\", 1, true), Raw(" ", 1, false));
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// Language tag.
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t!(Body, "``` hi```" => Raw(" hi", 3, true));
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t!(Body, "```rust hi```" => Raw("rust hi", 3, true));
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t!(Body, r"``` hi\````" => Raw(r" hi\", 3, true), Raw("", 1, false));
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t!(Body, "``` not `y`e`t finished```" => Raw(" not `y`e`t finished", 3, true));
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t!(Body, "```js \r\n document.write(\"go\")`"
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=> Raw("js \r\n document.write(\"go\")`", 3, false));
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// More backticks.
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t!(Body, "`````` ``````hi" => Raw(" ", 6, true), T("hi"));
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t!(Body, "````\n```js\nalert()\n```\n````" => Raw("\n```js\nalert()\n```\n", 4, true));
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}
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#[test]
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fn tokenize_escaped_symbols() {
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t!(Body, r"\\" => T(r"\"));
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t!(Body, r"\[" => T("["));
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t!(Body, r"\]" => T("]"));
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t!(Body, r"\*" => T("*"));
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t!(Body, r"\_" => T("_"));
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t!(Body, r"\`" => T("`"));
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t!(Body, r"\/" => T("/"));
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t!(Body, r"\u{2603}" => UE("2603", true));
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t!(Body, r"\u{26A4" => UE("26A4", false));
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t!(Body, r#"\""# => T("\""));
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}
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#[test]
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fn tokenize_unescapable_symbols() {
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t!(Body, r"\a" => T("\\"), T("a"));
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t!(Body, r"\:" => T(r"\"), T(":"));
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t!(Body, r"\=" => T(r"\"), T("="));
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t!(Body, r"\u{2GA4" => UE("2", false), T("GA4"));
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t!(Body, r"\u{ " => UE("", false), Space(0));
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t!(Body, r"\u" => T("\\"), T("u"));
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t!(Header, r"\\\\" => Invalid(r"\\\\"));
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t!(Header, r"\a" => Invalid(r"\a"));
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t!(Header, r"\:" => Invalid(r"\"), Colon);
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t!(Header, r"\=" => Invalid(r"\"), Equals);
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t!(Header, r"\," => Invalid(r"\"), Comma);
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}
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#[test]
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fn tokenize_header_tokens() {
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t!(Header, "__main__" => Id("__main__"));
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t!(Header, "_func_box" => Id("_func_box"));
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t!(Header, ">main" => Invalid(">main"));
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t!(Header, "🌓, 🌍," => Invalid("🌓"), Comma, S(0), Invalid("🌍"), Comma);
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t!(Header, "{abc}" => LB, Id("abc"), RB);
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t!(Header, "(1,2)" => LP, Int(1), Comma, Int(2), RP);
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t!(Header, "12_pt, 12pt" => Invalid("12_pt"), Comma, S(0), Len(Length::pt(12.0)));
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t!(Header, "f: arg >> g" => Id("f"), Colon, S(0), Id("arg"), S(0), Chain, S(0), Id("g"));
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t!(Header, "=3.15" => Equals, Float(3.15));
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t!(Header, "arg, _b, _1" => Id("arg"), Comma, S(0), Id("_b"), Comma, S(0), Id("_1"));
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t!(Header, "a:b" => Id("a"), Colon, Id("b"));
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t!(Header, "(){}:=," => LP, RP, LB, RB, Colon, Equals, Comma);
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t!(Body, "c=d, " => T("c=d,"), S(0));
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t!(Body, "a: b" => T("a:"), S(0), T("b"));
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t!(Header, "a: true, x=1" => Id("a"), Colon, S(0), Bool(true), Comma, S(0),
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Id("x"), Equals, Int(1));
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}
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#[test]
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fn tokenize_numeric_values() {
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t!(Header, "12.3e5" => Float(12.3e5));
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t!(Header, "120%" => Percent(120.0));
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t!(Header, "12e4%" => Percent(120000.0));
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t!(Header, "1e5in" => Len(Length::inches(100000.0)));
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t!(Header, "2.3cm" => Len(Length::cm(2.3)));
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t!(Header, "02.4mm" => Len(Length::mm(2.4)));
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t!(Header, "2.4.cm" => Invalid("2.4.cm"));
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t!(Header, "#6ae6dd" => Hex("6ae6dd"));
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t!(Header, "#8A083c" => Hex("8A083c"));
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}
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#[test]
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fn tokenize_strings() {
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t!(Body, "a \"hi\" string" => T("a"), S(0), T("\"hi\""), S(0), T("string"));
|
|
t!(Header, "\"hello" => Str("hello", false));
|
|
t!(Header, "\"hello world\"" => Str("hello world", true));
|
|
t!(Header, "\"hello\nworld\"" => Str("hello\nworld", true));
|
|
t!(Header, r#"1"hello\nworld"false"# => Int(1), Str("hello\\nworld", true), Bool(false));
|
|
t!(Header, r#""a\"bc""# => Str(r#"a\"bc"#, true));
|
|
t!(Header, r#""a\\"bc""# => Str(r#"a\\"#, true), Id("bc"), Str("", false));
|
|
t!(Header, r#""a\tbc"# => Str("a\\tbc", false));
|
|
t!(Header, "\"🌎\"" => Str("🌎", true));
|
|
}
|
|
|
|
#[test]
|
|
fn tokenize_math() {
|
|
t!(Header, "12e-3in" => Len(Length::inches(12e-3)));
|
|
t!(Header, "-1" => Min, Int(1));
|
|
t!(Header, "--1" => Min, Min, Int(1));
|
|
t!(Header, "- 1" => Min, S(0), Int(1));
|
|
t!(Header, "6.1cm + 4pt,a=1*2" => Len(Length::cm(6.1)), S(0), Plus, S(0), Len(Length::pt(4.0)),
|
|
Comma, Id("a"), Equals, Int(1), Star, Int(2));
|
|
t!(Header, "(5 - 1) / 2.1" => LP, Int(5), S(0), Min, S(0), Int(1), RP,
|
|
S(0), Slash, S(0), Float(2.1));
|
|
}
|
|
}
|