Files
carbon-lang/toolchain/parse/handle_let.cpp
T
Geoff Romer 4a0cf6c1fb Track the start of a signature more accurately (#6760)
This change ensures that a function signature always starts with an
`IdentifierNameMaybeBeforeSignature` node (renamed from
`IdentifierNameBeforeParams`), even in the case of function declarations
like `fn F -> T` that have no parameter list. As a consequence, this
ensures that we push new entries onto `pattern_block_stack` and
`full_pattern_stack` when we start processing the function signature.
2026-02-23 22:46:03 +00:00

114 lines
3.9 KiB
C++

// Part of the Carbon Language project, under the Apache License v2.0 with LLVM
// Exceptions. See /LICENSE for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
#include "toolchain/diagnostics/diagnostic.h"
#include "toolchain/lex/token_kind.h"
#include "toolchain/parse/context.h"
#include "toolchain/parse/handle.h"
#include "toolchain/parse/node_kind.h"
namespace Carbon::Parse {
auto HandleLet(Context& context) -> void {
auto state = context.PopState();
// These will start at the `let`.
context.PushState(state, StateKind::LetFinishAsRegular);
context.PushState(state, StateKind::LetAfterPatternAsRegular);
// This will start at the pattern.
context.PushState(StateKind::Pattern);
}
auto HandleAssociatedConstant(Context& context) -> void {
auto state = context.PopState();
// Parse the associated constant pattern: identifier :! type
auto identifier = context.ConsumeIf(Lex::TokenKind::Identifier);
if (!identifier) {
CARBON_DIAGNOSTIC(ExpectedAssociatedConstantIdentifier, Error,
"expected identifier in associated constant declaration");
context.emitter().Emit(*context.position(),
ExpectedAssociatedConstantIdentifier);
state.has_error = true;
}
auto colon_exclaim = context.ConsumeIf(Lex::TokenKind::ColonExclaim);
if (identifier && !colon_exclaim) {
CARBON_DIAGNOSTIC(ExpectedAssociatedConstantColonExclaim, Error,
"found runtime binding pattern in associated constant "
"declaration; expected a `:!` binding");
context.emitter().Emit(*context.position(),
ExpectedAssociatedConstantColonExclaim);
state.has_error = true;
}
if (!identifier || !colon_exclaim) {
auto end_token = context.SkipPastLikelyEnd(*(context.position() - 1));
context.AddNode(NodeKind::AssociatedConstantDecl, end_token,
/*has_error=*/true);
state.has_error = true;
return;
}
context.AddLeafNode(NodeKind::IdentifierNameNotBeforeSignature, *identifier);
state.token = *colon_exclaim;
context.PushState(state, StateKind::LetFinishAsAssociatedConstant);
context.PushState(state, StateKind::LetAfterPatternAsAssociatedConstant);
context.PushState(StateKind::Expr);
}
static auto HandleLetAfterPattern(Context& context, NodeKind init_kind)
-> void {
auto state = context.PopState();
if (state.has_error) {
if (auto after_pattern =
context.FindNextOf({Lex::TokenKind::Equal, Lex::TokenKind::Semi})) {
context.SkipTo(*after_pattern);
}
}
if (auto equals = context.ConsumeIf(Lex::TokenKind::Equal)) {
context.AddLeafNode(init_kind, *equals);
context.PushState(StateKind::Expr);
}
}
auto HandleLetAfterPatternAsRegular(Context& context) -> void {
HandleLetAfterPattern(context, NodeKind::LetInitializer);
}
auto HandleLetAfterPatternAsAssociatedConstant(Context& context) -> void {
auto state = context.PopState();
context.AddNode(NodeKind::AssociatedConstantNameAndType, state.token,
state.has_error);
context.PushState(state);
HandleLetAfterPattern(context, NodeKind::AssociatedConstantInitializer);
}
static auto HandleLetFinish(Context& context, NodeKind node_kind) -> void {
auto state = context.PopState();
auto end_token = state.token;
if (context.PositionIs(Lex::TokenKind::Semi)) {
end_token = context.Consume();
} else {
context.DiagnoseExpectedDeclSemi(Lex::TokenKind::Let);
state.has_error = true;
end_token = context.SkipPastLikelyEnd(state.token);
}
context.AddNode(node_kind, end_token, state.has_error);
}
auto HandleLetFinishAsRegular(Context& context) -> void {
HandleLetFinish(context, NodeKind::LetDecl);
}
auto HandleLetFinishAsAssociatedConstant(Context& context) -> void {
HandleLetFinish(context, NodeKind::AssociatedConstantDecl);
}
} // namespace Carbon::Parse