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https://github.com/carbon-language/carbon-lang.git
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josh11bandJon Ross-Perkins
03bf22e55e
Use two different nodes for "<type> followed by `as`" and "<type> omitted before `as`, use `self`", so it is easier to determine which case. Later the second case will push the type id for `self` onto the node stack, making the two paths more similar. --------- Co-authored-by: Jon Ross-Perkins <jperkins@google.com>
81 lines
2.8 KiB
C++
81 lines
2.8 KiB
C++
// Part of the Carbon Language project, under the Apache License v2.0 with LLVM
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// Exceptions. See /LICENSE for license information.
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// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
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#include "toolchain/parse/context.h"
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namespace Carbon::Parse {
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static auto ExpectAsOrTypeExpression(Carbon::Parse::Context& context) -> void {
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if (context.PositionIs(Lex::TokenKind::As)) {
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// as <expression> ...
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context.AddLeafNode(NodeKind::DefaultSelfImplAs, context.Consume());
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context.PushState(State::Expr);
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} else {
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// <expression> as <expression>...
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context.PushState(State::ImplBeforeAs);
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context.PushStateForExpr(PrecedenceGroup::ForImplAs());
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}
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}
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auto HandleImplAfterIntroducer(Carbon::Parse::Context& context) -> void {
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auto state = context.PopState();
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state.state = State::DeclOrDefinitionAsImpl;
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context.PushState(state);
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if (context.PositionIs(Lex::TokenKind::Forall)) {
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// forall [<implicit parameter list>] ...
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context.PushState(State::ImplAfterForall);
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context.ConsumeAndDiscard();
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if (context.PositionIs(Lex::TokenKind::OpenSquareBracket)) {
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context.PushState(State::PatternListAsImplicit);
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} else {
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CARBON_DIAGNOSTIC(ImplExpectedAfterForall, Error,
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"Expected `[` after `forall` in `impl` declaration.");
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context.emitter().Emit(*context.position(), ImplExpectedAfterForall);
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context.ReturnErrorOnState();
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// If we aren't producing a node from the PatternListAsImplicit state,
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// we still need to create a node to be the child of the `ImplForall`
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// token created in the `ImplAfterForall` state.
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context.AddLeafNode(NodeKind::InvalidParse, *context.position(),
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/*has_error=*/true);
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}
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} else {
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// One of:
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// as <expression> ...
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// <expression> as <expression>...
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ExpectAsOrTypeExpression(context);
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}
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}
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auto HandleImplAfterForall(Carbon::Parse::Context& context) -> void {
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auto state = context.PopState();
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if (state.has_error) {
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context.ReturnErrorOnState();
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}
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context.AddNode(NodeKind::ImplForall, state.token, state.subtree_start,
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state.has_error);
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// One of:
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// as <expression> ...
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// <expression> as <expression>...
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ExpectAsOrTypeExpression(context);
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}
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auto HandleImplBeforeAs(Carbon::Parse::Context& context) -> void {
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auto state = context.PopState();
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if (auto as = context.ConsumeIf(Lex::TokenKind::As)) {
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context.AddNode(NodeKind::TypeImplAs, *as, state.subtree_start,
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state.has_error);
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context.PushState(State::Expr);
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} else {
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if (!state.has_error) {
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CARBON_DIAGNOSTIC(ImplExpectedAs, Error,
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"Expected `as` in `impl` declaration.");
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context.emitter().Emit(*context.position(), ImplExpectedAs);
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}
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context.ReturnErrorOnState();
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}
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}
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} // namespace Carbon::Parse
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