Function expect_token_variant

graphlite/src/ast/parser.rs:3476–3497

Expect a token that matches a predicate

(predicate: &F)

/// Expect a token that matches a predicate
fn expect_token_variant<F>(predicate: &F) -> impl Fn(&[Token]) -> IResult<&[Token], Token> + '_
where
    F: Fn(&Token) -> bool,
{
    move |tokens: &[Token]| {
        if let Some(token) = tokens.first() {
            if predicate(token) {
                Ok((&tokens[1..], token.clone()))
            } else {
                Err(nom::Err::Error(nom::error::Error::new(
                    tokens,
                    nom::error::ErrorKind::Tag,
                )))
            }
        } else {
            Err(nom::Err::Error(nom::error::Error::new(
                tokens,
                nom::error::ErrorKind::Tag,
            )))
        }
    }
}

/// Helper function to expect a specific identifier (case-insensitive)
fn expect_identifier(name: &str) -> impl Fn(&[Token]) -> IResult<&[Token], Token> + '_ {