Sorry, I got so wrapped up on the proposal that I forgot about your
example. :D
We can make replace_leading/trailing/prefix/suffix accept t | [t] and that
would solve your use case. We already accept only this subset on
starts_with? / ends_with?, so I think it is a natural extension here.
Then it will automatically work on trim_leading/trim_trailing, since those
just use the replace equivalents. Shall we go this route for now? Please
open up an issue and feel free to submit a PR. :)
I am not convinced on trim_prefix/trim_suffix yet though, but you can use
the replace functions to achieve the same.
On Wed, Mar 2, 2022 at 7:11 PM 'eksperimental' via elixir-lang-core <
elixir-lang-core@googlegroups.com> wrote:
> > So unless there is a strong
> > reason for adding this, rather than consistency, I would not go this
> > route.
>
> Personally I don't think it is an inconsistency because there is no
> equivalent of String.trim_leading/1 (or the equivalent makes no sense,
> or hardly has any use).
>
> The need for String.trim_prefix/2 is because what actually solves the
> problem (my use case) that I initially shows.
>
> String.trim_leading could be considered an addition for consistency,
> but I guess it could still be useful in some cases but its
> implementation would not be as optimal as Sting.trim_prefix/2' s.
>
>
> On Wed, 2 Mar 2022 14:56:19 +0100
> José Valim <jose.va...@dashbit.co> wrote:
>
> > Thanks for the proposal. I believe we don't support all patterns
> > because it will be inefficient, especially the suffix/trailing
> > functions. It is not necessarily trivial to implement it for regexes
> > either (and regexes have their own mechanism to represent
> > prefixes/suffixes).
> >
> > The reason we don't have "trim_prefix" and "trim_suffix" is because
> > there is no reasonable implementation of trim_prefix/1 and
> > trim_suffix/1 - where no pattern to trim on is given (for example, it
> > it to the behaviour of trim_leading/1 and trim_trailing/1). So we
> > could add trim_prefix/2 and trim_suffix/2, but then it is
> > inconsistent with other trim* functions. So unless there is a strong
> > reason for adding this, rather than consistency, I would not go this
> > route.
> >
> >
> >
> > On Wed, Mar 2, 2022 at 2:25 PM 'eksperimental' via elixir-lang-core <
> > elixir-lang-core@googlegroups.com> wrote:
> >
> > > When starting to work in this implementation was wondering what
> > > should be the return value of
> > >
> > > String.trim_leading("--__--abc", [" ", "-", "_"])
> > >
> > >
> > > and I realized that it should mimic String.replace_leading/3
> > > Therefore it should returning "abc"
> > >
> > > Which leads me to think we should introduce String.trim_prefix/2,
> > > in order to be consistent with String.replace_prefix/3
> > > where the same input as above should behave like this:
> > >
> > > iex> String.trim_prefix("--__--abc", [" ", "-", "_"])
> > > "__--abc"
> > >
> > > Which also makes me think that String.replace_prefix should also
> > > behave like String.replace/3 where the second argument (match) is a
> > > pattern, not a string (ie. a string, list of strings, or a compiled
> > > search pattern). By introducing this last consistency change, the
> > > implementation of the consistency changes for the other functions
> > > mentioned above is straight-forward.
> > >
> > > So in short this consistency proposals suggests some functions to
> > > support t:String.pattern/0 which could be a string, a list of
> > > strings, or a compiled search pattern.
> > >
> > > 1. `String.replace_{leading, prefix, suffix, trailing}/3` to
> > > support in its second argument (match) t:String.pattern/0. Current
> > > String.replace/4 supports t:String.pattern/0 | t:Regex.t/0, but for
> > > the sake of simplifying this proposal I would leave out
> > > Regexes out of the equation for now.
> > >
> > > 2. Introduce String.trim_{prefix, suffix}/2 which will support
> > > t:String.pattern/0 as a its second arguments. These functions should
> > > mimic String.replace_{prefix, suffix}/2
> > >
> > > 3. Add support for t:String.pattern/0 for String.{trim,
> > > trim_leading, trim_trailing}/2 to support t:String.pattern/0 as its
> > > second argument. These functions should mimic String.{replace,
> > > replace_leading, replace_trailing}/3
> > >
> > > Please let me know what you think.
> > >
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> >
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