From: "Eregon (Benoit Daloze)" <redmine@...>
Date: 2013-01-31T01:19:04+09:00
Subject: [ruby-core:51760] [ruby-trunk - Bug #5536] String#start_with? and end_with? ignore arguments convertible to a String [PATCH]


Issue #5536 has been updated by Eregon (Benoit Daloze).


prijutme4ty (Ilya Vorontsov) wrote:
> =begin
> Can you please explain, why not just make (({"str".start_with(/s/)})) behave as (({"str".match(/^s/)})) ?
> =end

See #3388 for this feature (this issue is closed).
It is the approach I initially took, but building and compiling a Regexp is expensive, and so it should be cached or another way be used. For #start_with?, there is a C-level API for matching only at start, but there is no corresponding API for #end_with?.
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Bug #5536: String#start_with? and end_with? ignore arguments convertible to a String [PATCH]
https://bugs.ruby-lang.org/issues/5536#change-35731

Author: Eregon (Benoit Daloze)
Status: Closed
Priority: Normal
Assignee: matz (Yukihiro Matsumoto)
Category: core
Target version: 2.0.0
ruby -v: ruby 2.0.0dev (2011-11-01 trunk 33605) [x86_64-linux]


Hi,

Currently, String#start_with? and String#end_with? ignore arguments not convertible to String.

I believe it should instead raise an error,
 as it may lead to false expectations from the user and
 it is inconsistent with the rest of the API.

For example, if I try to use start_with? with a RegExp (which would be a nice feature BTW):
  "str".start_with? /s/ # => false
I believe it should be:
  "str".start_with? /s/ # => TypeError: can't convert Regexp into String

If you prefer the current behavior, could you explain me why?

P.S.: There is no test for String#{start,end}_with? in test/, should I add one or is it enough to change RubySpec (which I'll do when this gets accepted)?


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