parse.y:5671
static NODE *
dyna_init(node, pre)
    NODE *node;
    struct RVarmap *pre;
{
    struct RVarmap *post = ruby_dyna_vars;
    NODE *var;

    if (!node || !post || pre == post) return node;
    for (var = 0; post != pre && post->id; post = post->next) {
	var = NEW_DASGN_CURR(post->id, var);
    }
    return block_append(var, node);
}
