mikros/rust
1
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity

Rework pattern and expression nonterminal kinds.

Browse Source 
Merge `PatParam`/`PatWithOr`, and `Expr`/`Expr2021`, for a few reasons.

- It's conceptually nice, because the two pattern kinds and the two
  expression kinds are very similar.

- With expressions in particular, there are several places where both
  expression kinds get the same treatment.

- It removes one unreachable match arm.

- Most importantly, for #124141 I will need to introduce a new type
  `MetaVarKind` that is very similar to `NonterminalKind`, but records a
  couple of extra fields for expression metavars. It's nicer to have a
  single `MetaVarKind::Expr` expression variant to hold those extra
  fields instead of duplicating them across two variants
  `MetaVarKind::{Expr,Expr2021}`. And then it makes sense for patterns
  to be treated the same way, and for `NonterminalKind` to also be
  treated the same way.

I also clarified the comments, because I have long found them a little
hard to understand.
This commit is contained in:
Nicholas Nethercote 2024-06-23 08:13:56 +10:00
parent 0c5a75a61b
commit 5faf95c1c1
1 changed files with 3 additions and 3 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

6
src/parse/macros/mod.rs
View File

@ -1,4 +1,4 @@
use rustc_ast::token::{Delimiter, NonterminalKind, TokenKind}; use rustc_ast::token::{Delimiter, NonterminalKind, NtExprKind::*, NtPatKind::*, TokenKind};
use rustc_ast::tokenstream::TokenStream; use rustc_ast::tokenstream::TokenStream;
use rustc_ast::{ast, ptr}; use rustc_ast::{ast, ptr};
use rustc_parse::parser::{ForceCollect, Parser, Recovery}; use rustc_parse::parser::{ForceCollect, Parser, Recovery};
@ -48,7 +48,7 @@ macro_rules! parse_macro_arg {
parse_macro_arg!( parse_macro_arg!(
Expr, Expr,
NonterminalKind::Expr, NonterminalKind::Expr(Expr),
|parser: &mut Parser<'b>| parser.parse_expr(), |parser: &mut Parser<'b>| parser.parse_expr(),
|x: ptr::P<ast::Expr>| Some(x) |x: ptr::P<ast::Expr>| Some(x)
); );
@ -60,7 +60,7 @@ macro_rules! parse_macro_arg {
); );
parse_macro_arg!( parse_macro_arg!(
Pat, Pat,
NonterminalKind::PatParam { inferred: false }, NonterminalKind::Pat(PatParam { inferred: false }),
|parser: &mut Parser<'b>| parser.parse_pat_no_top_alt(None, None), |parser: &mut Parser<'b>| parser.parse_pat_no_top_alt(None, None),
|x: ptr::P<ast::Pat>| Some(x) |x: ptr::P<ast::Pat>| Some(x)
); );