[jira] [Created] (GROOVY-7433) API inconsistency between takeWhile, dropWhile and collectReplacements for CharSequences

["Paul King (JIRA)" <ji...@apache.org>]

Paul King created GROOVY-7433:
---------------------------------

             Summary: API inconsistency between takeWhile, dropWhile and collectReplacements for CharSequences
                 Key: GROOVY-7433
                 URL: https://issues.apache.org/jira/browse/GROOVY-7433
             Project: Groovy
          Issue Type: Bug
          Components: groovy-jdk
            Reporter: Paul King
            Assignee: Paul King


When treating Strings as an iterable collection of characters, Groovy provides each character as a String of size 1, e.g.:
{code}
assert "hello".toList() == ['h', 'e', 'l', 'l', 'o']
assert "hello".toList()[0].class.name == 'java.lang.String'
"hello".each {
  assert it instanceof String
}
{code}
There are just 3 methods where this isn't the case:
takeWhile, dropWhile and collectReplacements.
These methods supply a Character instead, e.g.:
{code}
assert "he" == "hello".takeWhile {
  assert it instanceof Character
  it != 'l'
}
{code}
This issue is to fix this inconsistency. This is a breaking change but of low impact:
* Most expressions within the closure such as {{it != 'A'}} or {{it < 'B'}} will produce the same results regardless of whether a String or character is passed in.
* Expressions using methods from the String class would have needed an "as String" or ".toString()" coercion/conversion. These will still work unchanged but the coercion will no longer be required.(Which aligns them with the expressions for all other String iteration methods.)
* Closures with an explicit String arg currently don't work but would work after the change.
* Closures making use of instance methods from the Character class are breaking but those methods are "charValue()" and "compareTo(Character anotherCharacter)" and are likely rarely used (there use would be non-idiomatic Groovy).
In any case, I propose supporting the detection of supplied Closures having a char or Character argument in which case the char would be passed in as now. This would make fixing the break trivial for those cases.



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