Re: Generalize and standarize dired-plural-s

[Kaushal Modi <kaushal.modi@gmail.com>]

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On Sun, Sep 18, 2016, 10:00 AM Tino Calancha <tino.calancha@gmail.com>
wrote:

>
> Hi,
>
> I)
> dired.el introduces the function `dired-plural-s' to pluralize
> correctly output messages as:
> (format "Kill Dired buffer%s of %s, too? "
>          (dired-plural-s (length buf-list))
>          (file-name-nondirectory fn))
>
> In this example, it returns "s" if (length buf-list) > 1.  Otherwise,
> it returns "".
> Of course, this task is not exclusive of Dired: many other packages
> in Emacs source code do the same thing.
>

I agree. I have also had something in my emacs config that made me wish of
the existence of a function like this.


> II)
> As you know, for some words the plural is different that just
> appending "s" to the end.  For instance, in message.el:
> (format
>   "Really use %s possibly unknown group%s: %s? "
>   (if (= (length errors) 1) "this" "these")
>   (if (= (length errors) 1) "" "s")
>   (mapconcat 'identity errors ", "))
>
> "this" -> "these" is not handled by `dired-plural-s'.
>
> I am wondering if it has sense to add a standard function,
> `string-plural-s', covering both cases: I), II).


+1


> Then, we might do
> `dired-plural-s' and alias for the new function.
> We might update all the 'plularizations' in Emacs source code to use
> the new function as well.
>
> Following function could do the job:
>
> (defun string-plural-s (arg &optional string plural)
>    "\
> Return plural of STRING if ARG is nil, or an integer >1, or a seq of
> length >1.
> If ARG is =1 or a sequence of length =1, return STRING.
> Optional arg PLURAL is the plural of STRING.
> If STRING is nil, return \"s\" or \"\"."
>    (let ((single (or string ""))
>          (plural (if (and string plural) plural
>                    (apply #'string (append string "s" nil)))))
>      (cond ((natnump arg)
>             (if (= arg 1) single plural))
>            ((null arg) plural)
>            ((consp arg)
>             (if (null (cdr arg)) single plural))
>            ((arrayp arg)
>             (if (= (length arg) 1) single plural))
>            (t
>             (signal 'wrong-type-argument
>                     (list arg 'natnump 'listp 'arrayp))))))


>
> What do you think about this idea?
>

I like this idea.

The only comment I have is that the "append 's' to pluralize" part should
not be hard-coded into the string-plural-s function.

How about have a "string-plural--conditions-function" variable (or
something named like that), and then you funcall that variable in
string-plural-s?

The "string-plural--conditions-function" variable would be a lambda
function that would accept an arg STRING and output a plural string for
that STRING.

Inside the lambda, would be an elaborate cond form that would decide how to
pluralize the string

this -> these
grape -> grapes
knife -> knives
ruby -> rubies
sheep -> sheep

This  "string-plural--conditions-function" variable will be quite an
elaborate cond form as it would try to cover all the corner cases of
English pluralization. I am suggesting this to be a separate function so
that the logic of string-plural-s stays clear and succinct and the English
grammar rules do not come in the way while understanding that function.

-- 

Kaushal Modi

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