Crate announce_core 

The implementation behind #[announce] and #[derive(Announce)], as plain functions, and the helpers for callbacks and checks. Do not depend on this crate: go through announce, which re-exports the public API as announce::machinery and announce::helper.

A proc-macro crate cannot export functions, so the code behind the macros lives here, in an ordinary library. announce-macros is a thin wrapper around it. The crate name and layout are not a stable interface.

The API of the generation is announce(), derive_announce() and Options (announce::machinery). See their docs, and announce::machinery for how a library uses them. helper is what callbacks and checks use (announce::helper): the parser of the tokens a trampoline sends, and the macros callback! and transformer!.

Modules

helper

Helpers for proc-macro crates that use announce trampolines: announce::helper.

Macros

callback

Defines a #[proc_macro] callback that parses its Input and turns syn::Errors into compile errors. The body returns syn::Result<proc_macro2::TokenStream>.

transformer

Defines a transformer: a #[proc_macro] that gets the newest entry as an Entry, rewrites it (the body returns syn::Result<Entry>), and forwards it to the next list element.

Structs

Check

One check or meta entry of the attribute: path or path(args).

Options

The parsed arguments of #[announce(..)] or of the #[announce(..)] helper attribute of #[derive(Announce)].

Enums

Layout

How the generated trampoline holds the item (layout = .., advanced).

Constants

SINGLE_COPY_THRESHOLD

Tokens (delimiters of a group counted) from which layout = auto holds the item once (Layout::Single) instead of copying it into each arm (Layout::Direct), counted on the escaped payload plus META.

Functions

announce

Does what #[announce(attr)] does to item.

define_repeater

Does what define_repeater!($vis $ident) does: the definition of the repeater trait, as type-leak writes it (type_leak::repeater_definition).

derive_announce

Does what #[derive(Announce)] does to its input.

derive_announce_with

Like derive_announce(), with the options given in code instead of a helper attribute. Any #[announce(..)] attribute on the input is removed and ignored.

finish

What the hidden macro finish! of the announce crate does: the end of the attribute query that #[announce(check, ..)] and the derives send through their checks (see crate::helper::attrs for the protocol).

try_announce

announce() with the error returned as a syn::Error.

try_define_repeater

define_repeater() with the error returned as a syn::Error.

try_derive_announce

derive_announce() with the error returned as a syn::Error.

try_finish

finish() with the error returned as a syn::Error.