mirror of
https://github.com/carbon-language/carbon-lang.git
synced 2026-09-25 21:20:10 +01:00
Jeremy G. Siek
b784458aef
* parameterized impls, first step * bug fixes, comments, etc. * added another test case, fix a bug in impl lookup * simplify tests, removing tuple stuff * don't create impl bindings for -bound implicit parameters * remove a redundant 'private' * CamelCase * add missing backtick * add a comment
117 lines
4.2 KiB
C++
117 lines
4.2 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 "executable_semantics/interpreter/impl_scope.h"
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#include "executable_semantics/interpreter/type_checker.h"
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#include "executable_semantics/interpreter/value.h"
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#include "llvm/ADT/StringExtras.h"
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#include "llvm/Support/Casting.h"
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using llvm::cast;
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namespace Carbon {
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void ImplScope::Add(Nonnull<const Value*> iface, Nonnull<const Value*> type,
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Nonnull<Expression*> impl) {
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Add(iface, {}, type, {}, impl);
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}
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void ImplScope::Add(Nonnull<const Value*> iface,
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llvm::ArrayRef<Nonnull<const GenericBinding*>> deduced,
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Nonnull<const Value*> type,
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llvm::ArrayRef<Nonnull<const ImplBinding*>> impl_bindings,
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Nonnull<Expression*> impl) {
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impls_.push_back({.interface = iface,
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.deduced = deduced,
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.type = type,
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.impl_bindings = impl_bindings,
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.impl = impl});
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}
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void ImplScope::AddParent(Nonnull<const ImplScope*> parent) {
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parent_scopes_.push_back(parent);
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}
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auto ImplScope::Resolve(Nonnull<const Value*> iface_type,
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Nonnull<const Value*> type, SourceLocation source_loc,
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const TypeChecker& type_checker) const
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-> ErrorOr<Nonnull<Expression*>> {
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ASSIGN_OR_RETURN(
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std::optional<Nonnull<Expression*>> result,
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TryResolve(iface_type, type, source_loc, *this, type_checker));
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if (!result.has_value()) {
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return CompilationError(source_loc) << "could not find implementation of "
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<< *iface_type << " for " << *type;
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}
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return *result;
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}
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auto ImplScope::TryResolve(Nonnull<const Value*> iface_type,
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Nonnull<const Value*> type,
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SourceLocation source_loc,
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const ImplScope& original_scope,
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const TypeChecker& type_checker) const
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-> ErrorOr<std::optional<Nonnull<Expression*>>> {
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ASSIGN_OR_RETURN(
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std::optional<Nonnull<Expression*>> result,
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ResolveHere(iface_type, type, source_loc, original_scope, type_checker));
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for (Nonnull<const ImplScope*> parent : parent_scopes_) {
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ASSIGN_OR_RETURN(std::optional<Nonnull<Expression*>> parent_result,
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parent->TryResolve(iface_type, type, source_loc,
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original_scope, type_checker));
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if (parent_result.has_value()) {
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if (result.has_value()) {
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return CompilationError(source_loc) << "ambiguous implementations of "
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<< *iface_type << " for " << *type;
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} else {
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result = *parent_result;
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}
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}
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}
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return result;
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}
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auto ImplScope::ResolveHere(Nonnull<const Value*> iface_type,
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Nonnull<const Value*> impl_type,
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SourceLocation source_loc,
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const ImplScope& original_scope,
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const TypeChecker& type_checker) const
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-> ErrorOr<std::optional<Nonnull<Expression*>>> {
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if (iface_type->kind() != Value::Kind::InterfaceType) {
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FATAL() << "expected an interface, not " << *iface_type;
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}
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const auto& iface = cast<InterfaceType>(*iface_type);
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std::optional<Nonnull<Expression*>> result = std::nullopt;
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for (const Impl& impl : impls_) {
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std::optional<Nonnull<Expression*>> m = type_checker.MatchImpl(
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iface, impl_type, impl, original_scope, source_loc);
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if (m.has_value()) {
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if (result.has_value()) {
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return CompilationError(source_loc)
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<< "ambiguous implementations of " << *iface_type << " for "
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<< *impl_type;
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} else {
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result = *m;
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}
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}
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}
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return result;
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}
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// TODO: Add indentation when printing the parents.
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void ImplScope::Print(llvm::raw_ostream& out) const {
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out << "impls: ";
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llvm::ListSeparator sep;
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for (const Impl& impl : impls_) {
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out << sep << *(impl.type) << " as " << *(impl.interface);
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}
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out << "\n";
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for (const Nonnull<const ImplScope*>& parent : parent_scopes_) {
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out << *parent;
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}
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}
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} // namespace Carbon
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