[#107430] [Ruby master Feature#18566] Merge `io-wait` gem into core IO — "byroot (Jean Boussier)" <noreply@...>
Issue #18566 has been reported by byroot (Jean Boussier).
22 messages
2022/02/02
[ruby-core:107718] [Ruby master Feature#18597] Strings need a named method like `dup` that doesn't duplicate if receiver is mutable
From:
"danh337 (Dan H)" <noreply@...>
Date:
2022-02-22 19:02:27 UTC
List:
ruby-core #107718
Issue #18597 has been updated by danh337 (Dan H).
Eregon (Benoit Daloze) wrote in #note-10:
> I meant code in a gem or in some open-source repository, so we can see the context and the need.
My team has needed this in its own code. I have given a pattern for it. I don't have time to search for examples from all gems or repos in the world.
> That example seems a clear case for String interpolation:
> ```ruby
> "#{some_object.send(a_method)}blah"
> ```
That is not the same code. You are always making a new String. I thought `.+@` only dups if the receiver is frozen. The `a_method` result could be mutable.
> > and I don't want to raise exception if I don't absolutely have to
>
> That is I believe an anti-pattern.
> Concretely, a method should either take a String and will never mutate it, or it needs a mutable String/a buffer (and will or can mutate it).
> What I'm saying is "might or might not mutate the argument (depending on frozen state)" is a bad design.
> A method should be clear about what it expects, it's very hard to work with a method which might mutate or not what you give it.
Thanks for sharing your opinions.
I know your job here is to weed out frivolous requests, but this experience makes me sad. Wasting time.
My team will continue to use the awkward `.+@` where we need it, or I will add a name for it in our own extensions lib.
----------------------------------------
Feature #18597: Strings need a named method like `dup` that doesn't duplicate if receiver is mutable
https://bugs.ruby-lang.org/issues/18597#change-96641
* Author: danh337 (Dan H)
* Status: Open
* Priority: Normal
----------------------------------------
This is related to #16295, but focuses only on the `.+@` part.
Currently we can use `.dup` in a method chain when we need to mutate a String.
However there are cases where the code's context *expects* the String to be mutated. In cases like this, `.dup` always works, but we don't want to duplicate a String that is already mutable.
Since `.+@` looks more like an operator, it can be unintuitive in a method chain, so this is asking for a new named method that can be used in its place, instead of always `.dup`.
For example:
```
def add_result_text(buffer, new_result)
text = "#{new_result.count} #{new_result.input} #{do_fancy_calc(new_result)}\n"
buffer.dup_if_immutable << text
# ^^^^^^^^^^^^^^^^ new method?
end
buffer = "" # ...maybe immutable
get_lots_of_results.each do |result|
buffer = add_result_text(buffer, result) # In case it was dup'ed
end
```
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