mirror of
https://github.com/carbon-language/carbon-lang.git
synced 2026-09-24 22:02:23 +01:00
Richard Smith
3884d3c27e
On the parsing side, we treat `a.(b)` as a member access whose second operand is a `ParenExpr` rather than a `MemberName`. A new node category is added for the union of `MemberName` and `ParenExpr` to support this. Checking is mostly reusing the same pieces we already have for simple member access. Compound member access is in most ways a simplified form of simple member access because it doesn't need to do any lookup.
92 lines
3.7 KiB
C++
92 lines
3.7 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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// Handles PeriodAs variants and ArrowExpr.
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// TODO: This currently only supports identifiers on the rhs, but will in the
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// future need to handle things like `object.(Interface.member)` for qualifiers.
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static auto HandlePeriodOrArrow(Context& context, NodeKind node_kind,
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State paren_state, bool is_arrow) -> void {
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auto state = context.PopState();
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// We're handling `.something` or `->something`.
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auto dot = context.ConsumeChecked(is_arrow ? Lex::TokenKind::MinusGreater
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: Lex::TokenKind::Period);
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if (context.ConsumeAndAddLeafNodeIf(Lex::TokenKind::Identifier,
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NodeKind::IdentifierName)) {
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// OK, `.` identifier.
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} else if (node_kind != NodeKind::QualifiedName &&
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context.ConsumeAndAddLeafNodeIf(Lex::TokenKind::Base,
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NodeKind::BaseName)) {
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// OK, `.base`. This is allowed in any name context other than declaring a
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// new qualified name: `fn Namespace.base() {}`
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} else if (paren_state != State::Invalid &&
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context.PositionIs(Lex::TokenKind::OpenParen)) {
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state.state = paren_state;
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context.PushState(state);
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context.PushState(State::ParenExpr);
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return;
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} else {
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CARBON_DIAGNOSTIC(ExpectedIdentifierAfterDotOrArrow, Error,
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"Expected identifier after `{0}`.", llvm::StringLiteral);
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context.emitter().Emit(
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*context.position(), ExpectedIdentifierAfterDotOrArrow,
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is_arrow ? llvm::StringLiteral("->") : llvm::StringLiteral("."));
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// If we see a keyword, assume it was intended to be a name.
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// TODO: Should keywords be valid here?
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if (context.PositionKind().is_keyword()) {
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context.AddLeafNode(NodeKind::IdentifierName, context.Consume(),
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/*has_error=*/true);
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} else {
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context.AddLeafNode(NodeKind::IdentifierName, *context.position(),
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/*has_error=*/true);
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// Indicate the error to the parent state so that it can avoid producing
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// more errors.
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context.ReturnErrorOnState();
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}
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}
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context.AddNode(node_kind, dot, state.subtree_start, state.has_error);
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}
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auto HandlePeriodAsDecl(Context& context) -> void {
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HandlePeriodOrArrow(context, NodeKind::QualifiedName, State::Invalid,
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/*is_arrow=*/false);
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}
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auto HandlePeriodAsExpr(Context& context) -> void {
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HandlePeriodOrArrow(context, NodeKind::MemberAccessExpr,
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State::CompoundMemberAccess,
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/*is_arrow=*/false);
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}
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auto HandlePeriodAsStruct(Context& context) -> void {
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HandlePeriodOrArrow(context, NodeKind::StructFieldDesignator, State::Invalid,
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/*is_arrow=*/false);
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}
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auto HandleArrowExpr(Context& context) -> void {
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HandlePeriodOrArrow(context, NodeKind::PointerMemberAccessExpr,
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State::CompoundPointerMemberAccess,
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/*is_arrow=*/true);
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}
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auto HandleCompoundMemberAccess(Context& context) -> void {
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auto state = context.PopState();
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context.AddNode(NodeKind::MemberAccessExpr, state.token, state.subtree_start,
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state.has_error);
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}
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auto HandleCompoundPointerMemberAccess(Context& context) -> void {
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auto state = context.PopState();
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context.AddNode(NodeKind::PointerMemberAccessExpr, state.token,
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state.subtree_start, state.has_error);
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}
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} // namespace Carbon::Parse
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