From 940b3170c1fb51e31fa3396f0a71fc8db9ac096c Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?=E5=8D=9C=E9=83=A8=E6=98=8C=E5=B9=B3?= Date: Thu, 21 Jul 2022 18:00:04 +0900 Subject: document for commit 5bbba76489628f450949 [ci skip] --- include/ruby/internal/eval.h | 33 ++++++++++++++++++++++++++++++--- 1 file changed, 30 insertions(+), 3 deletions(-) (limited to 'include') diff --git a/include/ruby/internal/eval.h b/include/ruby/internal/eval.h index 34a53849da..5bcbb97746 100644 --- a/include/ruby/internal/eval.h +++ b/include/ruby/internal/eval.h @@ -28,10 +28,12 @@ RBIMPL_SYMBOL_EXPORT_BEGIN() RBIMPL_ATTR_NONNULL(()) /** - * Evaluates the given string in an isolated binding. + * Evaluates the given string. * - * Here "isolated" means that the binding does not inherit any other - * bindings. This behaves same as the binding for required libraries. + * In case it is called from within a C-backended method, the evaluation is + * done under the current binding. However there can be no method. On such + * situation this function evaluates in an isolated binding, like `require` + * runs in a separate one. * * `__FILE__` will be `"(eval)"`, and `__LINE__` starts from 1 in the * evaluation. @@ -39,6 +41,31 @@ RBIMPL_ATTR_NONNULL(()) * @param[in] str Ruby code to evaluate. * @exception rb_eException Raises an exception on error. * @return The evaluated result. + * + * @internal + * + * @shyouhei's old tale about the birth and growth of this function: + * + * At the beginning, there was no rb_eval_string(). @shyouhei heard that + * @shugo, author of Apache httpd's mod_ruby module, requested @matz for this + * API. He wanted a way so that mod_ruby can evaluate ruby scripts one by one, + * separately, in each different contexts. So this function was made. It was + * designed to be a global interpreter entry point like ruby_run_node(). + * + * The way it is implemented however allows extension libraries (not just + * programs like Apache httpd) to call this function. Because its name says + * nothing about the initial design, people started to think of it as an + * orthodox way to call ruby level `eval` method from their extension + * libraries. Even our `extension.rdoc` has had a description of this function + * basically according to this understanding. + * + * The old (mod_ruby like) usage still works. But over time, usages of this + * function from extension libraries got popular, while mod_ruby faded out; is + * no longer maintained now. Devs decided to actively support both. This + * function now auto-detects how it is called, and switches how it works + * depending on it. + * + * @see https://bugs.ruby-lang.org/issues/18780 */ VALUE rb_eval_string(const char *str); -- cgit v1.2.1