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https://issues.apache.org/jira/browse/GROOVY-11636?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17947168#comment-17947168
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Paul King edited comment on GROOVY-11636 at 4/25/25 12:09 AM:
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The intention is for something which doesn't try to do anything smart with
codepoints, like the existing {{{}next()/++{}}}:
{code:groovy}
assert ++'🍑' == '🍒' // existing
assert '🍑'.next() == '🍒' // existing
assert '🍌'.next(5) == '🍑'
assert '🍌'.next(6) == '🍒'
assert ++'🙋🏻' == '🙋🏼' // existing
assert (0..9).collect('🍌'::next).join() == '🍌🍍🍎🍏🍐🍑🍒🍓🍔🍕'
assert '👩🍳'.next(9) == '👩🍼'
assert '👩🍳'.next(32) == '👩🎓'
assert '👩🍳'.next(10) == '👩🍽'
{code}
So, if you give a unicode sequence where it doesn't make sense to increment the
last character, you might get something you don't expect. E.g. the last example
above with next(10) ends up being "woman" + ZWJ + "dinnerplate" which isn't a
recognised combination like the earlier examples. Increment on the ZWJ or the
wrapping past Character.MAX_VALUE would also cause weirds combinations - but
that is what was asked for!
was (Author: paulk):
The intention is for something which doesn't try to do anything smart with
codepoints, like the existing {{{}next()/++{}}}:
{code:groovy}
assert ++'🍑' == '🍒' // existing
assert '🍑'.next() == '🍒' // existing
assert '🍌'.next(5) == '🍑'
assert '🍌'.next(6) == '🍒'
assert ++'🙋🏻' == '🙋🏼' // existing
assert (0..8).collect('🍏'::next).join() == '🍏🍐🍑🍒🍓🍔🍕🍖🍗'
assert '👩🍳'.next(9) == '👩🍼'
assert '👩🍳'.next(32) == '👩🎓'
assert '👩🍳'.next(10) == '👩🍽'
{code}
So, if you give a unicode sequence where it doesn't make sense to increment the
last character, you might get something you don't expect. E.g. the last example
above with next(10) ends up being "woman" + ZWJ + "dinnerplate" which isn't a
recognised combination like the earlier examples. Increment on the ZWJ or the
wrapping past Character.MAX_VALUE would also cause weirds combinations - but
that is what was asked for!
> Create a SGM#next which also takes an integer increment value
> -------------------------------------------------------------
>
> Key: GROOVY-11636
> URL: https://issues.apache.org/jira/browse/GROOVY-11636
> Project: Groovy
> Issue Type: New Feature
> Reporter: Paul King
> Assignee: Paul King
> Priority: Major
>
> Trying to get from String 'a' to 'e' by "adding 4" can be cumbersome, either
> calling next() multiple times, or converting to a char, doing the arithmetic,
> then converting back.
> The idea would be to support:
> {code:groovy}
> assert 'a'.next(0) == 'a'
> assert 'a'.next(4) == 'e'
> assert 'a'.next(0) == 'a'
> assert 'a'.next(25) == 'z'
> assert 'A'.next(32) == 'a'
> assert (0..4).collect('a'::next) == 'a'..'e'
> assert 'car'.next(2) == 'cat'
> {code}
> Although hopefully never used, this piggybacks on the normal next() wrapping
> behavior if Character.MAX_VALUE is reached. And also, like next(), applies
> the the last character in a longer String as per last test above.
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