rustc_span

Module hygiene

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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
    In order to have good line stepping behavior in debugger, for the given span we return its outermost macro call site that still has a #[collapse_debuginfo(yes)] property on it. We also stop walking call sites at the function body level because no line stepping can occur at the level above that. The returned span can then be used in emitted debuginfo.