cynic_parser/schema_coordinates/
lexer.rs

1use std::fmt;
2
3use logos::{Logos, SpannedIter};
4
5use crate::{
6    Span,
7    lexer::{LexicalError, Spanned, TokenExtras},
8    parser::AdditionalErrors,
9};
10
11pub struct Lexer<'input> {
12    // instead of an iterator over characters, we have a token iterator
13    token_stream: SpannedIter<'input, Token<'input>>,
14    input: &'input str,
15}
16
17impl<'input> Lexer<'input> {
18    pub fn new(input: &'input str) -> Self {
19        Self {
20            token_stream: Token::lexer(input).spanned(),
21            input,
22        }
23    }
24}
25
26impl<'input> Iterator for Lexer<'input> {
27    type Item = Spanned<Token<'input>, usize, AdditionalErrors>;
28
29    fn next(&mut self) -> Option<Self::Item> {
30        match self.token_stream.next() {
31            None => None,
32            Some((Ok(token), span)) => Some(Ok((span.start, token, span.end))),
33            Some((Err(_), span)) => {
34                Some(Err(AdditionalErrors::Lexical(LexicalError::InvalidToken(
35                    self.input[span.start..span.end].to_string(),
36                    Span::new(span.start, span.end),
37                ))))
38            }
39        }
40    }
41}
42
43/// Lexer for GraphQL schema coordinates: https://spec.graphql.org/September2025/#sec-Schema-Coordinates.Parsing-a-Schema-Coordinate
44#[derive(Logos, Copy, Clone, Debug, Eq, PartialEq, Ord, PartialOrd, Hash)]
45#[logos(extras = TokenExtras, skip r"[ \t\r\n\f,\ufeff]+|#[^\n\r]*")]
46pub enum Token<'a> {
47    // Valid tokens
48    #[token("@")]
49    At,
50
51    #[token(")")]
52    CloseParen,
53
54    #[token(":")]
55    Colon,
56
57    #[regex("[a-zA-Z_][a-zA-Z0-9_]*", |lex| lex.slice())]
58    Identifier(&'a str),
59
60    #[token("(")]
61    OpenParen,
62
63    #[token(".")]
64    Dot,
65}
66
67impl fmt::Display for Token<'_> {
68    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
69        f.write_str(match self {
70            Token::At => "at ('@')",
71            Token::CloseParen => "closing paren (')')",
72            Token::Colon => "colon (':')",
73            Token::Identifier(_) => "identifier",
74            Token::OpenParen => "opening paren ('(')",
75            Token::Dot => "dot ('.')",
76        })
77    }
78}
79
80impl From<lalrpop_util::ParseError<usize, Token<'_>, AdditionalErrors>> for crate::Error {
81    fn from(value: lalrpop_util::ParseError<usize, Token<'_>, AdditionalErrors>) -> Self {
82        use crate::Error;
83        use lalrpop_util::ParseError;
84
85        match value {
86            ParseError::InvalidToken { location } => Error::InvalidToken { location },
87            ParseError::UnrecognizedEof { location, expected } => {
88                Error::UnrecognizedEof { location, expected }
89            }
90            ParseError::UnrecognizedToken {
91                token: (lspan, token, rspan),
92                expected,
93            } => Error::UnrecognizedToken {
94                token: (lspan, token.to_string(), rspan),
95                expected,
96            },
97            ParseError::ExtraToken {
98                token: (lspan, token, rspan),
99            } => Error::ExtraToken {
100                token: (lspan, token.to_string(), rspan),
101            },
102            ParseError::User {
103                error: AdditionalErrors::Lexical(error),
104            } => Error::Lexical(error),
105            ParseError::User {
106                error: AdditionalErrors::MalformedString(error),
107            } => Error::MalformedStringLiteral(error),
108            ParseError::User {
109                error: AdditionalErrors::MalformedDirectiveLocation(lhs, location, rhs),
110            } => Error::MalformedDirectiveLocation(lhs, location, rhs),
111            ParseError::User {
112                error: AdditionalErrors::VariableInConstPosition(lhs, name, rhs),
113            } => Error::MalformedDirectiveLocation(lhs, name, rhs),
114        }
115    }
116}
cynic_parser/schema_coordinates/lexer.rs

cynic_parser/schema_coordinates/
lexer.rs
