Issue #22134 has been updated by nobu (Nobuyoshi Nakada). A small correction to my previous comment: `RB_SCAN_ARGS_BORROW_KEYWORDS` itself can be used for feature detection, so a separate `HAVE_RB_SCAN_ARGS_BORROW_KEYWORDS` is unnecessary. Extensions can define it as `""` when absent to share the same format string across Ruby versions. Also, how about naming the non-destructive API `rb_lookup_kwargs` rather than `rb_get_kwargs_const`? We could introduce `rb_extract_kwargs` as a more descriptive name for the existing destructive operation, while retaining `rb_get_kwargs` as a compatibility alias. ---------------------------------------- Feature #22134: Faster rb_scan_args() for keyword args (optimization) https://bugs.ruby-lang.org/issues/22134#change-118840 * Author: luke-gru (Luke Gruber) * Status: Open ---------------------------------------- ## Motivation When using the `rb_scan_args()` API, often we want to find a value for a given keyword argument. In order to do this, we call `rb_scan_args()` like so: ```c VALUE str; VALUE kwargs; VALUE example; rb_scan_args(argc, argv, "1:", &str, &kwargs); // duplicates the kwargs hash in argv if (!NIL_P(kwargs)) rb_get_kwargs(kwargs, &id_example, 0, 1, &example); // mutates the duplicated kwargs hash to retrieve `example:` ``` This duplicates the keyword args hash given in `argv`. It would be nice to be able to grab a direct reference to the keyword hash and to have a variant of `rb_get_kwargs()` that didn't mutate the passed in hash. ## Proposal Add a new valid format character for `rb_scan_args()`: ```c VALUE str; VALUE kwargs; VALUE example; rb_scan_args(argc, argv, "1:^", &str, &kwargs); // access kwargs directly from argv if (!NIL_P(kwargs)) rb_get_kwargs_const(kwargs, &id_example, 0, 1, &example); // don't mutate the passed kwargs hash ``` This '^' character would only be valid after a ":'. I have a [pull request](https://github.com/ruby/ruby/pull/17558) available for anyone that is interested. Thank you! -- https://bugs.ruby-lang.org/