Module rustc_expand::mbe

This module implements declarative macros: old macro_rules and the newer macro. Declarative macros are also known as "macro by example", and that's why we call this module mbe. For external documentation, prefer the official terminology: "declarative macros".

Modules

macro_check	Checks that meta-variables in macro definition are correctly declared and used.
macro_parser	This is an NFA-based parser, which calls out to the main rust parser for named non-terminals (which it commits to fully when it hits one in a grammar). There's a set of current NFA threads and a set of next ones. Instead of NTs, we have a special case for Kleene star. The big-O, in pathological cases, is worse than traditional use of NFA or Earley parsing, but it's an easier fit for Macro-by-Example-style rules.
macro_rules
quoted
transcribe

Structs

Delimited	Contains the sub-token-trees of a "delimited" token tree, such as the contents of (. Note that the delimiter itself might be NoDelim.
KleeneToken
SequenceRepetition

Enums

KleeneOp	A Kleene-style repetition operator for token sequences.
TokenTree	Similar to tokenstream::TokenTree, except that $i, $i:ident, and $(...) are "first-class" token trees. Useful for parsing macros.