Derive Macro Lexer

#[derive(Lexer)]
{
    // Attributes available to this derive:
    #[pattern]
    #[before]
    #[after]
    #[hook]
    #[lexerus]
    #[build_with]
}

Lexer

Decorates a struct or enum with impl Lexer<'code>.

Attributes

Outer

Lexerus

Remaps the module name

#[lexerus = "newname"]

Hook

A hook to run after the Lexer has successfullly lexed and produced a [Result::Ok]

#[derive(Lexer, Token, Debug)]
struct Trex<'code>(#[pattern = "rawr"] Buffer<'code>);

#[derive(Lexer, Token, Debug)]
#[hook(Self::hook)]
struct TaggedTrex<'code>(
    Trex<'code>,
    #[build_with(Ok(0))] usize,
);

impl<'code> TaggedTrex<'code> {
    fn hook(mut self) -> Result<Self, Error<'code>> {
        self.1 = 10;
        Ok(self)
    }
}

Before / After

Eats tokens before and after

#[derive(Lexer, Token, Debug)]
struct Ra<'code>(#[pattern = "ra"] Buffer<'code>);

#[derive(Lexer, Token, Debug)]
#[before(Quote, Ra)]
#[after(Quote)]
struct Wr<'code>(#[pattern = "wr"] Buffer<'code>);

Inner

Pattern

Either of the following can be used to mark a field which contains a buffer, which tells the lexer to match pattern at the start of the buffer

• #[pattern = "pat"]: Matches pat
• #[pattern("pat1", "pat2")]: Matchines pat1 or pat2

#[derive(Debug, Clone, Lexer, Token)]
pub struct LcLetter<'code>(
    #[pattern(
        "a", "b", "c", "d", "e", "f", "g", "h", "i", "j",
        "k", "l", "m", "n", "o", "p", "q", "r", "s", "t",
        "u", "v", "w", "x", "y", "z"
    )]
    Buffer<'code>,
);

Build with

Specify an expression which is used to build the annotated field Remaps the module name

#[derive(Lexer, Token, Debug)]
struct Trex<'code>(#[pattern = "rawr"] Buffer<'code>);

#[derive(Lexer, Token, Debug)]
struct BuiltRex<'code>(
    Trex<'code>,
    #[build_with(Ok(0))] usize,
);