JSParseNode *left, *right; jsint slot;
JSParseNode *pn2;
EmitElemOp(JSContext *cx, JSParseNode *pn, JSOp op, JSCodeGenerator *cg){    JSParseNode *left, *right;    jsint slot;    left = pn->pn_left;    right = pn->pn_right;    if (left->pn_type == TOK_NAME && right->pn_type == TOK_NUMBER) {        if (!LookupArgOrVar(cx, &cg->treeContext, left))            return JS_FALSE;        if (left->pn_op == JSOP_ARGUMENTS &&            JSDOUBLE_IS_INT(right->pn_dval, slot) &&            slot >= 0) {            EMIT_ATOM_INDEX_OP(JSOP_ARGSUB, (jsatomid)slot);            return JS_TRUE;        }    }