carbon-lang/toolchain/check/handle_variable.cpp

// Part of the Carbon Language project, under the Apache License v2.0 with LLVM
// Exceptions. See /LICENSE for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception

#include "toolchain/check/context.h"
#include "toolchain/check/convert.h"
#include "toolchain/sem_ir/node.h"

namespace Carbon::Check {

auto HandleVariableDeclaration(Context& context, Parse::Node parse_node)
    -> bool {
  // Handle the optional initializer.
  auto init_id = SemIR::NodeId::Invalid;
  bool has_init =
      context.parse_tree().node_kind(context.node_stack().PeekParseNode()) !=
      Parse::NodeKind::PatternBinding;
  if (has_init) {
    init_id = context.node_stack().PopExpression();
    context.node_stack()
        .PopAndDiscardSoloParseNode<Parse::NodeKind::VariableInitializer>();
  }

  // Extract the name binding.
  SemIR::NodeId bind_name_id =
      context.node_stack().Pop<Parse::NodeKind::PatternBinding>();
  auto bind_name = context.nodes().GetAs<SemIR::BindName>(bind_name_id);

  // Form a corresponding name in the current context, and bind the name to the
  // variable.
  context.declaration_name_stack().AddNameToLookup(
      context.declaration_name_stack().MakeUnqualifiedName(bind_name.parse_node,
                                                           bind_name.name_id),
      bind_name_id);

  // If there was an initializer, assign it to the storage.
  if (has_init) {
    auto var_id = bind_name.value_id;
    if (context.nodes().Get(var_id).Is<SemIR::VarStorage>()) {
      init_id = Initialize(context, parse_node, var_id, init_id);
      // TODO: Consider using different node kinds for assignment versus
      // initialization.
      context.AddNode(SemIR::Assign{parse_node, var_id, init_id});
    } else {
      // TODO: In a class scope, we should instead save the initializer
      // somewhere so that we can use it as a default.
      context.TODO(parse_node, "Field initializer");
    }
  }

  context.node_stack()
      .PopAndDiscardSoloParseNode<Parse::NodeKind::VariableIntroducer>();

  return true;
}

auto HandleVariableIntroducer(Context& context, Parse::Node parse_node)
    -> bool {
  // No action, just a bracketing node.
  context.node_stack().Push(parse_node);
  return true;
}

auto HandleVariableInitializer(Context& context, Parse::Node parse_node)
    -> bool {
  // No action, just a bracketing node.
  context.node_stack().Push(parse_node);
  return true;
}

}  // namespace Carbon::Check