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// Copyright (C) 2025 Free Software Foundation, Inc.
// This file is part of GCC.
// GCC is free software; you can redistribute it and/or modify it under
// the terms of the GNU General Public License as published by the Free
// Software Foundation; either version 3, or (at your option) any later
// version.
// GCC is distributed in the hope that it will be useful, but WITHOUT ANY
// WARRANTY; without even the implied warranty of MERCHANTABILITY or
// FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
// for more details.
// You should have received a copy of the GNU General Public License
// along with GCC; see the file COPYING3. If not see
// <http://www.gnu.org/licenses/>.
#include "rust-desugar-while-let.h"
#include "rust-ast.h"
#include "rust-hir-map.h"
#include "rust-path.h"
#include "rust-pattern.h"
#include "rust-stmt.h"
#include "rust-expr.h"
#include "rust-ast-builder.h"
namespace Rust {
namespace AST {
DesugarWhileLet::DesugarWhileLet () {}
MatchCase
DesugarWhileLet::DesugarCtx::make_break_arm ()
{
auto arm = builder.match_arm (builder.wildcard ());
auto break_expr
= std::unique_ptr<Expr> (new BreakExpr (tl::nullopt, nullptr, {}, loc));
return MatchCase (std::move (arm), std::move (break_expr));
}
MatchCase
DesugarWhileLet::DesugarCtx::make_continue_arm (
std::unique_ptr<Pattern> &&pattern, std::unique_ptr<BlockExpr> &&body)
{
auto arm = builder.match_arm (std::move (pattern));
return MatchCase (std::move (arm), std::move (body));
}
std::unique_ptr<Expr>
DesugarWhileLet::desugar (WhileLetLoopExpr &expr)
{
rust_assert (expr.get_patterns ().size () == 1);
auto pattern = expr.get_patterns ()[0]->clone_pattern ();
auto body = expr.get_loop_block ().clone_block_expr ();
auto scrutinee = expr.get_scrutinee_expr ().clone_expr ();
auto ctx = DesugarCtx (expr.get_locus ());
// _ => break,
auto break_arm = ctx.make_break_arm ();
// <pattern> => <body>,
auto continue_arm
= ctx.make_continue_arm (std::move (pattern), std::move (body));
// match <scrutinee> {
// <continue_arm>
// <break_arm>
// }
auto match_expr
= ctx.builder.match (std::move (scrutinee),
{std::move (continue_arm), std::move (break_arm)});
auto loop_stmts = std::vector<std::unique_ptr<Stmt>> ();
loop_stmts.emplace_back (ctx.builder.statementify (std::move (match_expr)));
// loop {
// <match_expr>
// }
return ctx.builder.loop (std::move (loop_stmts));
}
void
DesugarWhileLet::go (std::unique_ptr<Expr> &ptr)
{
rust_assert (ptr->get_expr_kind () == Expr::Kind::Loop);
auto &loop = static_cast<BaseLoopExpr &> (*ptr);
rust_assert (loop.get_loop_kind () == BaseLoopExpr::Kind::WhileLet);
auto &while_let = static_cast<WhileLetLoopExpr &> (loop);
auto desugared = DesugarWhileLet ().desugar (while_let);
ptr = std::move (desugared);
}
} // namespace AST
} // namespace Rust
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