[ruby-core:78717] [Ruby trunk Feature#9846] Regexp#to_regexp

Issue #9846 has been updated by Nobuyoshi Nakada.

Description updated

```ruby
case
when ary = Array.try_convert(o)
  # do something with ary
when str = String.try_convert(o)
  # do something with str
when re = Regexp.try_convert(o)
  # do something with re
else
  # do other thing
end
```

----------------------------------------
Feature #9846: Regexp#to_regexp
https://bugs.ruby-lang.org/issues/9846#change-62089

* Author: Wayne Conrad
* Status: Open
* Priority: Normal
* Assignee: 
* Target version: 
----------------------------------------
There should be `Regexp#to_regexp`, just as there is `Array#to_ary` and `String#to_str`.

```ruby
p [].to_ary       # => []
p ''.to_str       # => ""
p //.to_regexp    # undefined method `to_regexp`...
```

The use case is code like this:

```ruby
if o.respond_to?(:to_ary)
  # do something with o.to_ary
elsif o.respond_to?(:to_str)
  # do something with o.to_str
elsif o.respond_to?(to_regexp)    # can't do this today
  # do something with o.to_regexp
```

The workaround is to use `Regexp.try_convert`.  `Regexp.try_convert` accepts either a `Regexp` or an object that responds to `#to_regexp`; so this code works fine (and is in some ways better):

```ruby
elsif re = Regexp.try_convert(o)
  # do something with o
```

Still, that `Regexp` does not respond to `#to_regexp` surprised me.  Does it surprise anyone else?


---Files--------------------------------
0001-re.c-rb_reg_to_regexp-add-to_regexp.patch (2 KB)


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