mirror
/
rustc-dev-guide
mirror of https://github.com/rust-lang/rustc-dev-guide.git
1
0
Fork 0
Code Issues Packages Projects Releases Wiki Activity

Update links (#472)

This commit is contained in:
Yuki Okushi 2019-10-18 16:22:17 +09:00 committed by GitHub
parent 1d8db1a89d
commit eae74d3e18
1 changed files with 8 additions and 8 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

16
src/macro-expansion.md
View File

@ -7,7 +7,7 @@ before name resolution, macros are expanded using these portions of the code.
The macro parser, in turn, may call the normal Rust parser when it needs to The macro parser, in turn, may call the normal Rust parser when it needs to
bind a metavariable (e.g. `$my_expr`) while parsing the contents of a macro bind a metavariable (e.g. `$my_expr`) while parsing the contents of a macro
invocation. The code for macro expansion is in invocation. The code for macro expansion is in
[`src/libsyntax/ext/mbe/`][code_dir]. This chapter aims to explain how macro [`src/libsyntax_expand/mbe/`][code_dir]. This chapter aims to explain how macro
expansion works. expansion works.
### Example ### Example
@ -61,7 +61,7 @@ invocations. Interestingly, both are done by the macro parser.
Basically, the macro parser is like an NFA-based regex parser. It uses an Basically, the macro parser is like an NFA-based regex parser. It uses an
algorithm similar in spirit to the [Earley parsing algorithm similar in spirit to the [Earley parsing
algorithm](https://en.wikipedia.org/wiki/Earley_parser). The macro parser is algorithm](https://en.wikipedia.org/wiki/Earley_parser). The macro parser is
defined in [`src/libsyntax/ext/mbe/macro_parser.rs`][code_mp]. defined in [`src/libsyntax_expand/mbe/macro_parser.rs`][code_mp].
The interface of the macro parser is as follows (this is slightly simplified): The interface of the macro parser is as follows (this is slightly simplified):
@ -110,7 +110,7 @@ normal Rust parser.
As mentioned above, both definitions and invocations of macros are parsed using As mentioned above, both definitions and invocations of macros are parsed using
the macro parser. This is extremely non-intuitive and self-referential. The code the macro parser. This is extremely non-intuitive and self-referential. The code
to parse macro _definitions_ is in to parse macro _definitions_ is in
[`src/libsyntax/ext/mbe/macro_rules.rs`][code_mr]. It defines the pattern for [`src/libsyntax_expand/mbe/macro_rules.rs`][code_mr]. It defines the pattern for
matching for a macro definition as `$( $lhs:tt => $rhs:tt );+`. In other words, matching for a macro definition as `$( $lhs:tt => $rhs:tt );+`. In other words,
a `macro_rules` definition should have in its body at least one occurrence of a a `macro_rules` definition should have in its body at least one occurrence of a
token tree followed by `=>` followed by another token tree. When the compiler token tree followed by `=>` followed by another token tree. When the compiler
@ -139,7 +139,7 @@ the parse is ambiguous, while if there are no matches at all, there is a syntax
error. error.
For more information about the macro parser's implementation, see the comments For more information about the macro parser's implementation, see the comments
in [`src/libsyntax/ext/mbe/macro_parser.rs`][code_mp]. in [`src/libsyntax_expand/mbe/macro_parser.rs`][code_mp].
### Hygiene ### Hygiene
@ -205,8 +205,8 @@ TODO
TODO: maybe something about macros 2.0? TODO: maybe something about macros 2.0?
[code_dir]: https://github.com/rust-lang/rust/tree/master/src/libsyntax/ext/mbe [code_dir]: https://github.com/rust-lang/rust/tree/master/src/libsyntax_expand/mbe
[code_mp]: https://doc.rust-lang.org/nightly/nightly-rustc/syntax/ext/mbe/macro_parser [code_mp]: https://doc.rust-lang.org/nightly/nightly-rustc/syntax_expand/mbe/macro_parser
[code_mr]: https://doc.rust-lang.org/nightly/nightly-rustc/syntax/ext/mbe/macro_rules [code_mr]: https://doc.rust-lang.org/nightly/nightly-rustc/syntax_expand/mbe/macro_rules
[code_parse_int]: https://doc.rust-lang.org/nightly/nightly-rustc/syntax/ext/mbe/macro_parser/fn.parse.html [code_parse_int]: https://doc.rust-lang.org/nightly/nightly-rustc/syntax_expand/mbe/macro_parser/fn.parse.html
[parsing]: ./the-parser.html [parsing]: ./the-parser.html