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Differential D128708

[pseudo] Simplify/loosen the grammar around lambda captures.
ClosedPublic

Authored by sammccall on Jun 28 2022, 1:18 AM.

Details

Reviewers
hokein
Commits
rGaacefc817d93: [pseudo] Simplify/loosen the grammar around lambda captures.
Summary

Treat captures as a uniform list, rather than default-captures being special
snowflakes that may only appear at the start.

This accepts a larger set of (incorrect) code, and simplifies error-handling
by making this fit into the usual homogeneous-list pattern.

Diff Detail

Event Timeline

sammccall created this revision.Jun 28 2022, 1:18 AM
Herald added a project: Restricted Project. · View Herald TranscriptJun 28 2022, 1:18 AM
sammccall requested review of this revision.Jun 28 2022, 1:18 AM
Herald added a project: Restricted Project. · View Herald TranscriptJun 28 2022, 1:18 AM
Herald added subscribers: cfe-commits, alextsao1999. · View Herald Transcript
Harbormaster completed remote builds in B172412: Diff 440520.Jun 28 2022, 1:37 AM
hokein accepted this revision.Jun 28 2022, 6:41 AM
This revision is now accepted and ready to land.Jun 28 2022, 6:41 AM
Closed by commit rGaacefc817d93: [pseudo] Simplify/loosen the grammar around lambda captures. (authored by sammccall). · Explain WhyJun 28 2022, 6:56 AM
This revision was automatically updated to reflect the committed changes.
sammccall added a commit: rGaacefc817d93: [pseudo] Simplify/loosen the grammar around lambda captures..

Revision Contents

PathSize
clang-tools-extra/
pseudo/
lib/
12 lines
test/
cxx/
23 lines

Diff 440602

clang-tools-extra/pseudo/lib/cxx.bnf

Show First 20 Lines • Show All 70 Lines • ▼ Show 20 Lines
nested-name-specifier := :: nested-name-specifier := ::
nested-name-specifier := type-name :: nested-name-specifier := type-name ::
nested-name-specifier := namespace-name :: nested-name-specifier := namespace-name ::
nested-name-specifier := decltype-specifier :: nested-name-specifier := decltype-specifier ::
nested-name-specifier := nested-name-specifier IDENTIFIER :: nested-name-specifier := nested-name-specifier IDENTIFIER ::
nested-name-specifier := nested-name-specifier TEMPLATE_opt simple-template-id :: nested-name-specifier := nested-name-specifier TEMPLATE_opt simple-template-id ::
lambda-expression := lambda-introducer lambda-declarator_opt compound-statement lambda-expression := lambda-introducer lambda-declarator_opt compound-statement
lambda-expression := lambda-introducer < template-parameter-list > requires-clause_opt lambda-declarator_opt compound-statement lambda-expression := lambda-introducer < template-parameter-list > requires-clause_opt lambda-declarator_opt compound-statement
lambda-introducer := [ lambda-capture_opt ] #! We allow a capture-default to appear anywhere in a capture-list.
# This simplifies the grammar and error recovery.
lambda-introducer := [ capture-list_opt ]
lambda-declarator := ( parameter-declaration-clause_opt ) decl-specifier-seq_opt noexcept-specifier_opt trailing-return-type_opt requires-clause_opt lambda-declarator := ( parameter-declaration-clause_opt ) decl-specifier-seq_opt noexcept-specifier_opt trailing-return-type_opt requires-clause_opt
lambda-capture := capture-default
lambda-capture := capture-list
lambda-capture := capture-default , capture-list
capture-default := &
capture-default := =
capture-list := capture capture-list := capture
capture-list := capture-list , capture capture-list := capture-list , capture
capture := capture-default
capture := simple-capture capture := simple-capture
capture := init-capture capture := init-capture
capture-default := &
capture-default := =
simple-capture := IDENTIFIER ..._opt simple-capture := IDENTIFIER ..._opt
simple-capture := & IDENTIFIER ..._opt simple-capture := & IDENTIFIER ..._opt
simple-capture := THIS simple-capture := THIS
simple-capture := * THIS simple-capture := * THIS
init-capture := ..._opt IDENTIFIER initializer init-capture := ..._opt IDENTIFIER initializer
init-capture := & ..._opt IDENTIFIER initializer init-capture := & ..._opt IDENTIFIER initializer
fold-expression := ( cast-expression fold-operator ... ) fold-expression := ( cast-expression fold-operator ... )
fold-expression := ( ... fold-operator cast-expression ) fold-expression := ( ... fold-operator cast-expression )
▲ Show 20 Lines • Show All 665 Lines • Show Last 20 Lines

clang-tools-extra/pseudo/test/cxx/capture-list.cpp

  • This file was added.
// RUN: clang-pseudo -grammar=%cxx-bnf-file -source=%s --print-forest | FileCheck %s
// We loosely allow capture defaults in any position/multiple times.
auto lambda = [&, &foo, bar(x), =]{};
// CHECK: lambda-introducer := [ capture-list ]
// CHECK-NEXT: ├─[
// CHECK-NEXT: ├─capture-list
// CHECK-NEXT: │ ├─capture-list
// CHECK-NEXT: │ │ ├─capture-list
// CHECK-NEXT: │ │ │ ├─capture-list~& := tok[4]
// CHECK-NEXT: │ │ │ ├─,
// CHECK-NEXT: │ │ │ └─capture~simple-capture
// CHECK-NEXT: │ │ │ ├─&
// CHECK-NEXT: │ │ │ └─IDENTIFIER := tok[7]
// CHECK-NEXT: │ │ ├─,
// CHECK-NEXT: │ │ └─capture~init-capture
// CHECK-NEXT: │ │ ├─IDENTIFIER := tok[9]
// CHECK-NEXT: │ │ └─initializer := ( expression-list )
// CHECK-NEXT: │ │ ├─(
// CHECK-NEXT: │ │ ├─expression-list~IDENTIFIER := tok[11]
// CHECK-NEXT: │ │ └─)
// CHECK-NEXT: │ ├─,
// CHECK-NEXT: │ └─capture~=
// CHECK-NEXT: └─]