[ruby-core:96046] [Ruby master Feature#9602] Logic with `Enumerable#grep`

Issue #9602 has been updated by msnm (Masahiro Nomoto).


I agree with sawa's opinion.  `Enumerable#grep` and other methods using `===` internally should accept more than one arguments, following `when` conditions.

Yukihiro Matsumoto wrote:
> We should use #select for more complex filtering.

`#select` is highly versatile.  I think it's good that there is a filter method that has the ability between (current) `#grep` and `#select`.

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Feature #9602: Logic with `Enumerable#grep`
https://bugs.ruby-lang.org/issues/9602#change-82896

* Author: sawa (Tsuyoshi Sawada)
* Status: Feedback
* Priority: Normal
* Assignee: matz (Yukihiro Matsumoto)
* Target version: 
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`Enumerable#grep` is useful to filter things:

    [nil, {}, [], 1, :foo, "foo"].grep(String)
    # => ["foo"]

1. Often, the condition cannot be expressed as a single object on which `===` is applied, but as a disjunction over `===` applied to multiple objects. I would like `Enumerable#grep` to take arbitrary number of arguments, and when they are more than one, a logical disjunction applies, just as when there are multiple comma-separated objects after `when` in `case` condition:

        [nil, {}, [], 1, :foo, "foo"].grep(String, Symbol, Array)
        # => [[], :foo, "foo"]

2. Also, it often happens that I want the negation of grep. Perhaps, `Enumerable#grepv` (`grepv` comes from `grep -v`) can be implemented as negation of `Enumerable#grep`, i.e., select elements for which `===` returns false on any of the arguments:

        [nil, {}, [], 1, :foo, "foo"].grepv(String, Symbol, Array)
        # => [nil, {}, 1]

---Files--------------------------------
select-to-accept-args.patch (2.62 KB)


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