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https://github.com/carbon-language/carbon-lang.git
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Jon Ross-Perkins
8738497301
According to approved syntax at https://github.com/carbon-language/carbon-lang/blob/trunk/proposals/p3848.md#syntax-defined, `fn F[]` without explicit parameters should be valid. This makes it work, then adds some validation to prevent `class C[]` in check. Note that for `fn`, positional parameters are a TODO -- but this allows me to test validation in `fn destroy[]` which is rejected, not just a TODO.
113 lines
4.0 KiB
C++
113 lines
4.0 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_index.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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// Adds a leaf node for the name, and updates the state stack for parameter
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// handling.
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static auto HandleName(Context& context, Context::StateStackEntry state,
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Lex::TokenIndex name_token,
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NodeKind not_before_params_kind,
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NodeKind not_before_params_qualifier_kind,
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NodeKind before_params_kind) -> void {
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switch (context.PositionKind()) {
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case Lex::TokenKind::Period:
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context.AddLeafNode(not_before_params_kind, name_token);
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context.AddNode(not_before_params_qualifier_kind,
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context.ConsumeChecked(Lex::TokenKind::Period),
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state.has_error);
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context.PushState(State::DeclNameAndParams);
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break;
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case Lex::TokenKind::OpenSquareBracket:
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context.AddLeafNode(before_params_kind, name_token);
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state.state = State::DeclNameAndParamsAfterImplicit;
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context.PushState(state);
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context.PushState(State::PatternListAsImplicit);
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break;
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case Lex::TokenKind::OpenParen:
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context.AddLeafNode(before_params_kind, name_token);
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state.state = State::DeclNameAndParamsAfterParams;
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context.PushState(state);
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context.PushState(State::PatternListAsExplicit);
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break;
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default:
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context.AddLeafNode(not_before_params_kind, name_token);
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break;
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}
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}
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auto HandleDeclNameAndParams(Context& context) -> void {
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auto state = context.PopState();
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if (auto identifier = context.ConsumeIf(Lex::TokenKind::Identifier)) {
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HandleName(context, state, *identifier,
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NodeKind::IdentifierNameNotBeforeParams,
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NodeKind::IdentifierNameQualifierWithoutParams,
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NodeKind::IdentifierNameBeforeParams);
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return;
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}
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if (auto keyword = context.ConsumeIf(Lex::TokenKind::Destroy)) {
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HandleName(context, state, *keyword, NodeKind::KeywordNameNotBeforeParams,
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NodeKind::KeywordNameQualifierWithoutParams,
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NodeKind::KeywordNameBeforeParams);
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return;
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}
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Lex::TokenIndex token = *context.position();
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if (context.tokens().GetKind(token) == Lex::TokenKind::FileEnd) {
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// The end of file is an unhelpful diagnostic location. Instead, use the
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// introducer token.
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token = state.token;
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}
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if (state.token == *context.position()) {
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CARBON_DIAGNOSTIC(ExpectedDeclNameAfterPeriod, Error,
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"`.` should be followed by a name");
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context.emitter().Emit(token, ExpectedDeclNameAfterPeriod);
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} else {
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CARBON_DIAGNOSTIC(ExpectedDeclName, Error,
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"`{0}` introducer should be followed by a name",
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Lex::TokenKind);
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context.emitter().Emit(token, ExpectedDeclName,
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context.tokens().GetKind(state.token));
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}
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context.ReturnErrorOnState();
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context.AddInvalidParse(*context.position());
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}
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auto HandleDeclNameAndParamsAfterImplicit(Context& context) -> void {
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auto state = context.PopState();
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state.state = State::DeclNameAndParamsAfterParams;
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context.PushState(state);
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if (!context.PositionIs(Lex::TokenKind::OpenParen)) {
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return;
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}
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context.PushState(State::PatternListAsExplicit);
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}
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auto HandleDeclNameAndParamsAfterParams(Context& context) -> void {
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auto state = context.PopState();
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if (auto period = context.ConsumeIf(Lex::TokenKind::Period)) {
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auto start_kind = context.tree().node_kind(NodeId(state.subtree_start));
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auto node_kind = start_kind == NodeKind::IdentifierNameBeforeParams
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? NodeKind::IdentifierNameQualifierWithParams
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: NodeKind::KeywordNameQualifierWithParams;
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context.AddNode(node_kind, *period, state.has_error);
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context.PushState(State::DeclNameAndParams);
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}
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}
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} // namespace Carbon::Parse
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