forked from Orchid/orchid
46 lines
1.7 KiB
Rust
46 lines
1.7 KiB
Rust
use chumsky::{self, prelude::*, Parser};
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/// Parses a text character that is not the specified delimiter
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fn text_parser(delim: char) -> impl Parser<char, char, Error = Simple<char>> {
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// Copied directly from Chumsky's JSON example.
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let escape = just('\\').ignore_then(
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just('\\')
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.or(just('/'))
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.or(just('"'))
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.or(just('b').to('\x08'))
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.or(just('f').to('\x0C'))
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.or(just('n').to('\n'))
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.or(just('r').to('\r'))
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.or(just('t').to('\t'))
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.or(just('u').ignore_then(
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filter(|c: &char| c.is_digit(16))
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.repeated()
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.exactly(4)
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.collect::<String>()
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.validate(|digits, span, emit| {
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char::from_u32(u32::from_str_radix(&digits, 16).unwrap())
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.unwrap_or_else(|| {
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emit(Simple::custom(span, "invalid unicode character"));
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'\u{FFFD}' // unicode replacement character
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})
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}),
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)),
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);
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filter(move |&c| c != '\\' && c != delim).or(escape)
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}
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/// Parse a character literal between single quotes
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pub fn char_parser() -> impl Parser<char, char, Error = Simple<char>> {
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just('\'').ignore_then(text_parser('\'')).then_ignore(just('\''))
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}
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/// Parse a string between double quotes
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pub fn str_parser() -> impl Parser<char, String, Error = Simple<char>> {
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just('"')
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.ignore_then(
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text_parser('"').map(Some)
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.or(just("\\\n").map(|_| None)) // Newlines preceded by backslashes are ignored.
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.repeated()
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).then_ignore(just('"'))
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.flatten().collect()
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} |