Add Pluralize function for strings

[wilfwilson]

I've done some work towards making objects correctly pluralise the word 'generator' in GAP, especially in ViewString methods.

In English, you say that you have 0 generators, 1 generator, or n generators, in the case that n > 1. Most (all?) of the methods for ViewString or ViewObj in the library do not special case 1 generator, and instead write 1 generators.

So we get, for example:

<magma with 1 generators>

rather than

<magma with 1 generator>

The wrongness grates on me, and makes GAP seem that little bit less professional. Therefore, I've gone some way to addressing this. However, I have not spent the time to finish and polish this work, because:

1. Is there a good reason that I've missed for GAP to be this way?

2. Will changing all of these methods break the tests of so many packages that it's not worth doing?

3. My 'fixes' are ugly and repetitive. Really, I want a function that I can use from anyway in GAP, to return the string "generator" if the number of generators is 1, or "generators" otherwise. Any suggestions? How general should this be? That way I could adjust the string construction code to be something like:

"<group with ", nrgens, FUNC(" generator", "s", nrgens <> 1), ">";

where FUNC would print the concatenation of the first two arguments if the third is true, and only prints the first argument otherwise.

[wilfwilson]

Or maybe it should be

"<group with ", nrgens, " generator", ReturnIf(nrgens <> 1, "s"), ">";

where ReturnIf returns its second argument if the first argument is true, and returns nothing otherwise?

[ChrisJefferson]

I think a function would be better. Looking at the examples, perhaps do:

Pluralize(count, str), which returns the plural version of str if count <> 1. Pluralize, should take an optional 3rd argument which is the plural form of str, but most of the time we will just auto-pluralise, based on a simple set of rules (which we can decide).

One advantage for this is we could for now add some option to disable pluralizing, which could be a "quick hack" to not break package testing.

[olexandr-konovalov]

Agree with @ChrisJefferson. The new function could go under 27.9 Operations to Evaluate Strings.

[ChrisJefferson]

Just as an extension, I do agree with the plan to fix the pluralisation, and agree it looks bad.

[olexandr-konovalov]

That will be fun to implement properly :) https://en.wikipedia.org/wiki/English_plurals

[fingolfin]

Auto pluralization heuristics can easily cover 99% of the cases, and e.g. Ruby on Rails relies on it heavily (or at least used to when I last used it). Some references:

• https://apidock.com/rails/String/pluralize
• https://apidock.com/rails/ActiveSupport/Inflector
• https://github.com/rails/rails/blob/master/activesupport/lib/active_support/inflections.rb contains the actual rules; a lot of them are probably irrelevant for us (unless you are concerned about octopi and money(s)... ;-)

I think the main reason this isn't done in all parts of GAP is that it's extra work; and while I also find it grating to read, I also understand that sometimes, finishing your actual work is more important than scratching these itches ;-).

[wilfwilson]

Thanks for the input. I'll give look into adding a Pluralize function, and integrating it where possible.

I also understand that sometimes, finishing your actual work is more important than scratching these itches ;-)

Hence my "priority: low" tag ;-) But while I'm unemployed, I've decided I'll take some liberties!

[fingolfin]

Oh, sure, I didn't mean to shoot this project down, to the contrary, I am happy somebody works on it :-)

[coveralls]

Coverage increased (+0.003%) to 84.892% when pulling 839bf24 on wilfwilson:1-generators into 33bb643 on gap-system:master.

[fingolfin]

Really nice! I'd approve, except for that TODO in the documentation ;-)

[wilfwilson]

Hopefully this is now complete.

[fingolfin]

Looks good to me! I made a minor suggestion but that could be done in a future PR.

Just in case you are interested in taking this a little bit further: I found a few more things that could be adjusted to use Pluralize; I grepped for '" points' , '" vectors', '" elements', '" pts'

[wilfwilson]

I will make the changes that you suggest.

[wilfwilson]

I've done so @fingolfin.