Module rustc_span::hygiene

Machinery for hygienic macros.

Inspired by Matthew Flatt et al., “Macros That Work Together: Compile-Time Bindings, Partial Expansion, and Definition Contexts,” Journal of Functional Programming 22, no. 2 (March 1, 2012): 181–216, https://doi.org/10.1017/S0956796812000093.

Structs

• ExpnData
  A subset of properties from both macro definition and macro call available through global data. Avoid using this if you have access to the original definition or call structures.
• ExpnHash
  A unique hash value associated to an expansion.
• ExpnId
  A unique ID associated with a macro invocation and expansion.
• ExpnIndex
  A unique ID associated with a macro invocation and expansion.
• HygieneData 🔒
• HygieneDecodeContext
  Additional information used to assist in decoding hygiene data
• HygieneDecodeContextInner 🔒
  Additional information used to assist in decoding hygiene data
• HygieneEncodeContext
• LocalExpnId
  A unique ID associated with a macro invocation and expansion.
• SyntaxContext
  A SyntaxContext represents a chain of pairs (ExpnId, Transparency) named “marks”.
• SyntaxContextData

Enums

• AstPass
  The kind of AST transform.
• DesugaringKind
  The kind of compiler desugaring.
• ExpnKind
  Expansion kind.
• MacroKind
  The kind of macro invocation or definition.
• Transparency
  A property of a macro expansion that determines how identifiers produced by that expansion are resolved.

Functions

• assert_default_hashing_controls 🔒
  Assert that the provided HashStableContext is configured with the ‘default’ HashingControls. We should always have bailed out before getting to here with a non-default mode. With this check in place, we can avoid the need to maintain separate versions of ExpnData hashes for each permutation of HashingControls settings.
• debug_hygiene_data
• decode_expn_id
  Decode an expansion from the metadata of a foreign crate.
• decode_syntax_context
• for_all_ctxts_in 🔒
• for_all_expns_in 🔒
• raw_encode_syntax_context
• register_expn_id
  Register an expansion which has been decoded from the metadata of a foreign crate.
• register_local_expn_id
  Register an expansion which has been decoded from the on-disk-cache for the local crate.
• update_disambiguator 🔒
  Updates the disambiguator field of the corresponding ExpnData such that the Fingerprint of the ExpnData does not collide with any other ExpnIds.
• update_dollar_crate_names
• walk_chain
• walk_chain_collapsed