mirror of
https://github.com/carbon-language/carbon-lang.git
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Jon Ross-Perkins
446b0ce4ae
This started with cleaning up the remaining Name/expression type punning in the node stack, and grew. I'm factoring out a class because we've previously expressed the desire to factor logic out of SemanticsContext where possible, and this seemed like a reasonable cut. NameExpression as the first node as a QualifiedExpression allows the qualifier handling to consider Name in one less spot, an incremental simplification. However, the additional complexity caused by this makes me split ApplyNameQualifier/ApplyExpressionQualifier in order to avoid repeat checks of the parse node's kind. The logic is still largely shared, thus a couple helper functions. I think this is all fairly well structured in the isolated class. I can see that we may want to avoid passing SemanticsContext as an argument in the future if it elides a step of lookup.
126 lines
4.3 KiB
C++
126 lines
4.3 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/parser/parser_context.h"
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namespace Carbon {
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// Handles DeclarationNameAndParamsAs(Optional|Required).
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static auto ParserHandleDeclarationNameAndParams(ParserContext& context,
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ParserState after_name)
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-> void {
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auto state = context.PopState();
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// TODO: Should handle designated names.
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if (auto identifier = context.ConsumeIf(TokenKind::Identifier)) {
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state.state = after_name;
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context.PushState(state);
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if (context.PositionIs(TokenKind::Period)) {
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// Because there's a qualifier, we process the first segment as an
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// expression for simplicity. This just means semantics has one less thing
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// to handle here.
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context.AddLeafNode(ParseNodeKind::NameExpression, *identifier);
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state.state = ParserState::PeriodAsDeclaration;
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context.PushState(state);
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} else {
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context.AddLeafNode(ParseNodeKind::Name, *identifier);
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}
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} else {
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CARBON_DIAGNOSTIC(ExpectedDeclarationName, Error,
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"`{0}` introducer should be followed by a name.",
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TokenKind);
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context.emitter().Emit(*context.position(), ExpectedDeclarationName,
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context.tokens().GetKind(state.token));
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context.ReturnErrorOnState();
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context.AddLeafNode(ParseNodeKind::InvalidParse, *context.position());
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}
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}
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auto ParserHandleDeclarationNameAndParamsAsNone(ParserContext& context)
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-> void {
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ParserHandleDeclarationNameAndParams(
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context, ParserState::DeclarationNameAndParamsAfterNameAsNone);
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}
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auto ParserHandleDeclarationNameAndParamsAsOptional(ParserContext& context)
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-> void {
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ParserHandleDeclarationNameAndParams(
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context, ParserState::DeclarationNameAndParamsAfterNameAsOptional);
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}
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auto ParserHandleDeclarationNameAndParamsAsRequired(ParserContext& context)
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-> void {
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ParserHandleDeclarationNameAndParams(
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context, ParserState::DeclarationNameAndParamsAfterNameAsRequired);
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}
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enum class Params {
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None,
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Optional,
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Required,
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};
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static auto ParserHandleDeclarationNameAndParamsAfterName(
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ParserContext& context, Params params) -> void {
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auto state = context.PopState();
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if (context.PositionIs(TokenKind::Period)) {
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// Continue designator processing.
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context.PushState(state);
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state.state = ParserState::PeriodAsDeclaration;
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context.PushState(state);
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return;
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}
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if (params == Params::None) {
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return;
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}
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if (context.PositionIs(TokenKind::OpenSquareBracket)) {
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context.PushState(ParserState::DeclarationNameAndParamsAfterDeduced);
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context.PushState(ParserState::ParameterListAsDeduced);
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} else if (context.PositionIs(TokenKind::OpenParen)) {
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context.PushState(ParserState::ParameterListAsRegular);
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} else if (params == Params::Required) {
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CARBON_DIAGNOSTIC(ParametersRequiredByIntroducer, Error,
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"`{0}` requires a `(` for parameters.", TokenKind);
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context.emitter().Emit(*context.position(), ParametersRequiredByIntroducer,
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context.tokens().GetKind(state.token));
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context.ReturnErrorOnState();
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}
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}
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auto ParserHandleDeclarationNameAndParamsAfterNameAsNone(ParserContext& context)
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-> void {
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ParserHandleDeclarationNameAndParamsAfterName(context, Params::None);
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}
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auto ParserHandleDeclarationNameAndParamsAfterNameAsOptional(
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ParserContext& context) -> void {
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ParserHandleDeclarationNameAndParamsAfterName(context, Params::Optional);
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}
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auto ParserHandleDeclarationNameAndParamsAfterNameAsRequired(
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ParserContext& context) -> void {
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ParserHandleDeclarationNameAndParamsAfterName(context, Params::Required);
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}
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auto ParserHandleDeclarationNameAndParamsAfterDeduced(ParserContext& context)
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-> void {
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context.PopAndDiscardState();
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if (context.PositionIs(TokenKind::OpenParen)) {
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context.PushState(ParserState::ParameterListAsRegular);
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} else {
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CARBON_DIAGNOSTIC(
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ParametersRequiredByDeduced, Error,
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"A `(` for parameters is required after deduced parameters.");
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context.emitter().Emit(*context.position(), ParametersRequiredByDeduced);
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context.ReturnErrorOnState();
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}
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}
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} // namespace Carbon
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