protected internal override void VisitAST(AssignStmtAST node)
{
if (!HasId(node.Name))
{
RegisterId(node.Name, node.Value.RetType);
}
var(ty, addr) = GetId(node.Name);
this.Visit(node.Value);
GenCode.Add(Ins.Dpl(ty)); // duplicate the stack top first
GenCode.Add(Ins.Str(ty, 0, addr)); // then move to the specified addr, sp--
}