void ExprCompiler::visit(ForExpr& expr, int dest)
{
// TODO(bob): Hackish. An actual intermediate representation would help
// here.
int iterateMethod = compiler_.findMethod(String::create("0:iterate"));
ASSERT(iterateMethod != -1, "Should have 'iterate' method in core.");
int advanceMethod = compiler_.findMethod(String::create("0:advance"));
ASSERT(advanceMethod != -1, "Should have 'advance' method in core.");
// Evaluate the iteratable expression.
int iterator = makeTemp();
compile(expr.iterator(), iterator);
// Then call "iterate" on it to get an iterator.
// TODO(bob): Hackish. An actual intermediate representation would help
// here.
write(expr, OP_CALL, iterateMethod, iterator, iterator);
int loopStart = startJumpBack();
// Call "advance" on the iterator.
write(expr, OP_CALL, advanceMethod, iterator, dest);
// If done, jump to exit.
int doneSlot = makeTemp();
write(expr, OP_BUILT_IN, BUILT_IN_DONE, doneSlot);
write(expr, OP_EQUAL, dest, doneSlot, doneSlot);
int loopExit = startJump(expr);
releaseTemp(); // doneSlot.
// Match on the loop pattern.
compile(expr.pattern(), dest);
// Compile the body.
Loop loop(this);
compile(expr.body(), dest);
endJumpBack(expr, loopStart);
endJump(loopExit, OP_JUMP_IF_TRUE, doneSlot);
loop.end();
releaseTemp(); // iterator.
// TODO(bob): Need to figure out what the result value should be.
}
void Resolver::visit(ForExpr& expr, int dummy)
{
// Resolve the iterator in its own scope.
Scope iteratorScope(this);
resolve(expr.iterator());
iteratorScope.end();
// Resolve the body (including the loop pattern) in its own scope.
Scope loopScope(this);
scope_->resolve(*expr.pattern());
numLoops_++;
resolve(expr.body());
numLoops_--;
loopScope.end();
}