78 lines
2.6 KiB
Rust
78 lines
2.6 KiB
Rust
use logos::Logos;
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#[rustfmt::skip]
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#[derive(Logos, Debug, PartialEq, Eq, Clone, strum::Display)]
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pub enum Token {
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#[strum(serialize = "+") ] #[token("+") ] Plus,
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#[strum(serialize = "-") ] #[token("-") ] Minus,
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#[strum(serialize = "*") ] #[token("*") ] Times,
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#[strum(serialize = "/") ] #[token("/") ] Div,
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#[strum(serialize = "%") ] #[token("%") ] Mod,
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#[strum(serialize = "==")] #[token("==")] Equals,
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#[strum(serialize = "!=")] #[token("!=")] NotEquals,
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#[strum(serialize = "&&")] #[token("&&")] And,
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#[strum(serialize = "||")] #[token("||")] Or,
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#[strum(serialize = ">") ] #[token(">") ] GT,
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#[strum(serialize = "<") ] #[token("<") ] LT,
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#[strum(serialize = "?:")] #[token("?:")] Elvis,
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#[strum(serialize = "=~")] #[token("=~")] RegexMatch,
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#[strum(serialize = "!") ] #[token("!") ] Not,
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#[strum(serialize = ",") ] #[token(",") ] Comma,
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#[strum(serialize = "?") ] #[token("?") ] Question,
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#[strum(serialize = ":") ] #[token(":") ] Colon,
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#[strum(serialize = "(") ] #[token("(") ] LPren,
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#[strum(serialize = ")") ] #[token(")") ] RPren,
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#[strum(serialize = "[") ] #[token("[") ] LBrack,
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#[strum(serialize = "]") ] #[token("]") ] RBrack,
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#[strum(serialize = ".") ] #[token(".") ] Dot,
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#[strum(serialize = "true") ] #[token("true") ] True,
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#[strum(serialize = "false")] #[token("false")] False,
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#[regex(r"[a-zA-Z_-]+", |x| x.slice().to_string())]
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Ident(String),
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#[regex(r"[+-]?(?:[0-9]+[.])?[0-9]+", |x| x.slice().to_string())]
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NumLit(String),
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#[regex(r#""(?:[^"\\]|\\.)*""#, |x| x.slice().to_string())]
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StrLit(String),
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#[error]
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#[regex(r"[ \t\n\f]+", logos::skip)]
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Error,
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}
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#[derive(Debug, Eq, PartialEq, Copy, Clone)]
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pub struct LexicalError(usize, usize);
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impl std::fmt::Display for LexicalError {
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fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
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write!(f, "Lexical error at {}..{}", self.0, self.1)
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}
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}
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pub type SpannedResult<Tok, Loc, Error> = Result<(Loc, Tok, Loc), Error>;
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pub struct Lexer<'input> {
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lexer: logos::SpannedIter<'input, Token>,
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}
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impl<'input> Lexer<'input> {
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pub fn new(text: &'input str) -> Self {
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Lexer { lexer: logos::Lexer::new(text).spanned() }
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}
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}
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impl<'input> Iterator for Lexer<'input> {
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type Item = SpannedResult<Token, usize, LexicalError>;
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fn next(&mut self) -> Option<Self::Item> {
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let (token, range) = self.lexer.next()?;
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if token == Token::Error {
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Some(Err(LexicalError(range.start, range.end)))
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} else {
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Some(Ok((range.start, token, range.end)))
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}
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}
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}
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