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c33c9a02f6
Includes support for the `impls`, `=`, and `==` requirement operators to the right of a `where`, but `and` to allow multiple requirements is still a TODO. --------- Co-authored-by: Josh L <josh11b@users.noreply.github.com> Co-authored-by: Richard Smith <richard@metafoo.co.uk>
84 lines
2.5 KiB
C++
84 lines
2.5 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/lex/token_kind.h"
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#include "toolchain/parse/context.h"
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#include "toolchain/parse/handle.h"
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namespace Carbon::Parse {
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auto HandleRequirementBegin(Context& context) -> void {
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context.PopAndDiscardState();
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context.PushState(State::RequirementOperator);
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context.PushStateForExpr(PrecedenceGroup::ForRequirements());
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}
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auto HandleRequirementOperator(Context& context) -> void {
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auto state = context.PopState();
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switch (context.PositionKind()) {
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case Lex::TokenKind::Impls: {
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break;
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}
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case Lex::TokenKind::Equal: {
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break;
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}
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case Lex::TokenKind::EqualEqual: {
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break;
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}
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default: {
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if (!state.has_error) {
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CARBON_DIAGNOSTIC(
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ExpectedRequirementOperator, Error,
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"Requirement should use `impls`, `=`, or `==` operator.");
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context.emitter().Emit(*context.position(),
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ExpectedRequirementOperator);
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}
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context.ReturnErrorOnState();
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return;
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}
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}
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state.token = context.Consume();
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context.PushState(state, State::RequirementOperatorFinish);
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context.PushStateForExpr(PrecedenceGroup::ForRequirements());
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}
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auto HandleRequirementOperatorFinish(Context& context) -> void {
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auto state = context.PopState();
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switch (auto token_kind = context.tokens().GetKind(state.token)) {
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case Lex::TokenKind::Impls: {
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context.AddNode(NodeKind::RequirementImpls, state.token, state.has_error);
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break;
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}
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case Lex::TokenKind::Equal: {
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context.AddNode(NodeKind::RequirementEqual, state.token, state.has_error);
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break;
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}
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case Lex::TokenKind::EqualEqual: {
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context.AddNode(NodeKind::RequirementEqualEqual, state.token,
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state.has_error);
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break;
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}
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default:
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// RequirementOperatorFinish state is only pushed in
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// HandleRequirementOperator on one of the three requirement operator
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// tokens.
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CARBON_FATAL() << "Unexpected token kind for requirement operator: "
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<< token_kind;
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return;
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}
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// TODO: Handle `and` token.
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}
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auto HandleWhereFinish(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::WhereExpr, state.token, state.has_error);
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}
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} // namespace Carbon::Parse
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