[ruby-core:61000] [ruby-trunk - Feature #9553] Make argument validation routine of a method an object

Issue #9553 has been updated by Boris Stitnicky.


It is my fault that I was not aware of `Method#parameters` when writing this post. Too bad I did not participate in its naming, I would push for calling it `Method#arguments`. This method resolves the main reasons that led me to writing this post. This post can thus be closed at any time without harm. Yet, it remains worthy of consideration to make `#parameters` method return a special object rather than just `Array` as it does now.

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Feature #9553: Make argument validation routine of a method an object
https://bugs.ruby-lang.org/issues/9553#change-45402

* Author: Boris Stitnicky
* Status: Open
* Priority: Normal
* Assignee: 
* Category: 
* Target version: 
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Ruby methods have their acceptable argument configurations specified by special syntax. As argument fields has gotten more complex, simple `#arity` is no longer enough to capture the type of the argument field. I suggest making this argument validation routine (so far defined by special syntax) introspectible, and reusable for the purposes of metaprogramming. One possibility would be to have eg. `ArgumentValidator` and/or `UnboundArgumentValidator` objects just like we have method and unbound method objects. Then eg. `Method#argity` / `Proc#argity` would return that `ArgumentValidator` or `UnboundArgumentValidator`. The purpose of this post is not to suggest the final solution, but to bring attention to the problem of non-oo nature of built-in argument validation and the growing need to do something about that.



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