Testing whether a word is plural or not

[pdscopes]

As discussed in #28, this PR adds three new functions to the inflector class:

• is_plural - whether a word is plural or uncountable
• is_singular - whether a word is singular or uncountable
• is_uncountable - whether a word is uncountable

I have deliberately not added helper functions at this point as this functionality is fairly niche.

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Points raised in issue

Thanks for your suggestion, that could be useful. Instead of applying inflections and checking if the word changes, what do you think about using the plural and singular regexp available in the Inflections instance?

This was not possible because of the catchall regex like /$/.

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Known bugs

This PR does break the testing because, I believe, the inflections in some languages are incomplete, e.g.:

• Spanish: singularize('interés') = 'interé' which is incorrect
• Turkish: pluralize('kirazlar') = 'kirazlarlar' which is incorrect

Unfortunately, I am not a speaker of these languages and therefore cannot correct them confidently, however some imcomplete suggestions:

// lib/inflections/tr.php
  $inflect
  // Add the negative look behind: "(?<!l[ae]r)"
  ->plural('/([aoıu][^aoıueöiü]{0,6})(?<!l[ae]r)$/u', '\1lar')
  ->plural('/([eöiü][^aoıueöiü]{0,6})(?<!l[ae]r)$/u', '\1ler')
  // ...
     

// lib/inflections/es.php
  $inflect
  // ...
  // Add the negative look behind "(?<!eré)"
  ->singular('/(?<!eré)s$/', '\1')
  // ...

[olvlvl]

Hi Pete, thanks for the contribution. We have 68 nationalities at work I should be able to find somebody to confirm the Spanish and Turkish inflections. I'll have a look as soon as possible.

[pdscopes]

Amazing, FYI it is also failing on Norwegian "nb".

[olvlvl]

@pdscopes I implemented is_uncountable() over here: #32. Sorry I didn't have time to do more yet.

[pdscopes]

@olvlvl no worries, I've resolved the conflicts that #32 caused in this PR.