Struct MacroCtx 

pub struct MacroCtx<'r> {
    pub line: u32,
    pub span: Span,
    /* private fields */
}

Context passed to every macro expand invocation: gives access to the gensym counter (for hygienic identifier minting) and a back- reference to the registry (so a macro can call other macros programmatically — @if uses this to expand its chosen arm).

Fields

line: u32

Line of the @name invocation, for error attribution.

span: Span

Source span of the invocation (@ byte through last )/}), for Token::describe slicing on synthesized tokens.

Implementations

impl<'r> MacroCtx<'r>

pub fn gensym(&mut self, prefix: &str) -> Box<str>

Mint a fresh identifier name like __lm_42_tmp. Used by @gensym and any host-side macro that needs hygiene.