mirror of
https://github.com/carbon-language/carbon-lang.git
synced 2026-09-25 07:20:10 +01:00
Jon Meow
04ab30f231
The code is pretty intertwined: having the AST be truly mutable means (to me) changing parser.ypp to return non-const values, but then the way things are passed around between objects should be non-const (particularly an issue with lists), which then creates issues with construction of lists in the TypeChecker, which then TypeChecker needs to mostly be non-const. Due to the difficulties in breaking this apart, whereas I'd previously considering refactoring accessor naming in the same PR, I've largely avoided doing so. The intent is then that this PR focuses mainly on const -> non-const AST behavior. call_main moves out of interpreter.cpp so that interpreter.cpp can receive a fully const AST.
119 lines
4.0 KiB
C++
119 lines
4.0 KiB
C++
// 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 "executable_semantics/ast/pattern.h"
|
|
|
|
#include <string>
|
|
|
|
#include "common/ostream.h"
|
|
#include "executable_semantics/ast/expression.h"
|
|
#include "executable_semantics/common/arena.h"
|
|
#include "executable_semantics/common/error.h"
|
|
#include "llvm/ADT/StringExtras.h"
|
|
#include "llvm/Support/Casting.h"
|
|
|
|
namespace Carbon {
|
|
|
|
using llvm::cast;
|
|
|
|
void Pattern::Print(llvm::raw_ostream& out) const {
|
|
switch (Tag()) {
|
|
case Kind::AutoPattern:
|
|
out << "auto";
|
|
break;
|
|
case Kind::BindingPattern: {
|
|
const auto& binding = cast<BindingPattern>(*this);
|
|
if (binding.Name().has_value()) {
|
|
out << *binding.Name();
|
|
} else {
|
|
out << "_";
|
|
}
|
|
out << ": " << *binding.Type();
|
|
break;
|
|
}
|
|
case Kind::TuplePattern: {
|
|
const auto& tuple = cast<TuplePattern>(*this);
|
|
out << "(";
|
|
llvm::ListSeparator sep;
|
|
for (const TuplePattern::Field& field : tuple.Fields()) {
|
|
out << sep << field.name << " = " << *field.pattern;
|
|
}
|
|
out << ")";
|
|
break;
|
|
}
|
|
case Kind::AlternativePattern: {
|
|
const auto& alternative = cast<AlternativePattern>(*this);
|
|
out << *alternative.ChoiceType() << "." << alternative.AlternativeName()
|
|
<< *alternative.Arguments();
|
|
break;
|
|
}
|
|
case Kind::ExpressionPattern:
|
|
out << *cast<ExpressionPattern>(*this).Expression();
|
|
break;
|
|
}
|
|
}
|
|
|
|
TuplePattern::TuplePattern(Nonnull<Arena*> arena,
|
|
Nonnull<Expression*> tuple_literal)
|
|
: Pattern(Kind::TuplePattern, tuple_literal->SourceLoc()) {
|
|
const auto& tuple = cast<TupleLiteral>(*tuple_literal);
|
|
for (const FieldInitializer& init : tuple.Fields()) {
|
|
fields.push_back(
|
|
Field(init.name, arena->New<ExpressionPattern>(init.expression)));
|
|
}
|
|
}
|
|
|
|
auto PatternFromParenContents(Nonnull<Arena*> arena, SourceLocation loc,
|
|
const ParenContents<Pattern>& paren_contents)
|
|
-> Nonnull<Pattern*> {
|
|
std::optional<Nonnull<Pattern*>> single_term = paren_contents.SingleTerm();
|
|
if (single_term.has_value()) {
|
|
return *single_term;
|
|
} else {
|
|
return TuplePatternFromParenContents(arena, loc, paren_contents);
|
|
}
|
|
}
|
|
|
|
auto TuplePatternFromParenContents(Nonnull<Arena*> arena, SourceLocation loc,
|
|
const ParenContents<Pattern>& paren_contents)
|
|
-> Nonnull<TuplePattern*> {
|
|
return arena->New<TuplePattern>(
|
|
loc, paren_contents.TupleElements<TuplePattern::Field>(loc));
|
|
}
|
|
|
|
// Used by AlternativePattern for constructor initialization. Produces a helpful
|
|
// error for incorrect expressions, rather than letting a default cast error
|
|
// apply.
|
|
static auto RequireFieldAccess(Nonnull<Expression*> alternative)
|
|
-> FieldAccessExpression& {
|
|
if (alternative->Tag() != Expression::Kind::FieldAccessExpression) {
|
|
FATAL_PROGRAM_ERROR(alternative->SourceLoc())
|
|
<< "Alternative pattern must have the form of a field access.";
|
|
}
|
|
return cast<FieldAccessExpression>(*alternative);
|
|
}
|
|
|
|
AlternativePattern::AlternativePattern(SourceLocation loc,
|
|
Nonnull<Expression*> alternative,
|
|
Nonnull<TuplePattern*> arguments)
|
|
: Pattern(Kind::AlternativePattern, loc),
|
|
choice_type(RequireFieldAccess(alternative).Aggregate()),
|
|
alternative_name(RequireFieldAccess(alternative).Field()),
|
|
arguments(arguments) {}
|
|
|
|
auto ParenExpressionToParenPattern(Nonnull<Arena*> arena,
|
|
const ParenContents<Expression>& contents)
|
|
-> ParenContents<Pattern> {
|
|
ParenContents<Pattern> result = {
|
|
.elements = {}, .has_trailing_comma = contents.has_trailing_comma};
|
|
for (const auto& element : contents.elements) {
|
|
result.elements.push_back(
|
|
{.name = element.name,
|
|
.term = arena->New<ExpressionPattern>(element.term)});
|
|
}
|
|
return result;
|
|
}
|
|
|
|
} // namespace Carbon
|