Re: [PATCH] Add abbrev suggestions

[Eli Zaretskii <eliz@gnu.org>]

> Date: Sun, 19 Jul 2020 22:01:00 +0300
> From: Eli Zaretskii <eliz@gnu.org>
> Cc: emacs-devel@gnu.org
> 
> > From: Mathias Dahl <mathias.dahl@gmail.com>
> > Date: Sun, 19 Jul 2020 19:40:17 +0200
> > 
> > Could someone help out with the below?
> 
> Sorry your patch was forgotten.  If no one beats me to it, I will take
> care of it in a few days.  Stay tuned.

I have a few comments to your patch, mostly about the documentation
parts:

First, please accompany the patch with a ChangeLog-style commit log
message which describes the individual changes.  See CONTRIBUTE for
the style guidance.

>  (defvar abbrev-expand-function #'abbrev--default-expand
> -  "Function that `expand-abbrev' uses to perform abbrev expansion.
> +    "Function that `expand-abbrev' uses to perform abbrev expansion.

What is this whitespace change about?

> +(defcustom abbrev-suggest t
> +    "Non-nil means we should suggest abbrevs to the user.

Our style is "Non-nil means suggest abbrevs ..."

> +By enabling this option, if abbrev mode is enabled and if the
> +user has typed some text that exists as an abbrev, suggest to the
> +user to use the abbrev instead."
> +    :type 'boolean
> +    :group 'abbrev-mode)

Please always specify a :version tag in new and modified defcustoms
(here and elsewhere in your patch).

Are you sure it is a good idea to make this non-nil by default?
Wouldn't some users consider these suggestions an annoyance?

> +(defcustom abbrev-suggest-hint-threshold 3
> +    "Threshold for when to inform the user that there is an abbrev.
> +The threshold is the number of characters that differs between
                                                  ^^^^^^^
"differ", in plural.  I think.

> +the length of the abbrev and the length of the expansion.  The
> +thinking is that if the expansion is only one or a few characters
> +longer than the abbrev, the benefit of informing the user is not
> +that big.  If you always want to be informed, set this value to
> +`0' or less."

This doc string should mention abbrev-suggest, since it only has
effect if that is non-nil.

> +(defun abbrev--suggest-get-previous-words (n)
> +    "Return the previous N words, spaces included.

"Previous" as in "before point", I presume?  If so, please say that.

> +Changes newlines into spaces."
> +    (let ((end (point)))
> +      (save-excursion
> +	(backward-word n)
> +	(replace-regexp-in-string
> +	 "\\s " " "
> +	 (buffer-substring-no-properties (point) end)))))
> +
> +(defun abbrev--suggest-above-threshold (expansion)
> +    "Return t if we are above the threshold.

Who is "we" in this context?  This should be explained.

> +EXPANSION is a cons cell where the car is the expansion and the
> +cdr is the abbrev."

Our style is to include the arguments in the first sentence of the doc
string.

> +(defun abbrev--suggest-shortest-abbrev (new current)
> +    "Return the shortest abbrev.
> +NEW and CURRENT are cons cells where the `car' is the expansion

Same here.

> +(defun abbrev--suggest-get-totals ()
> +    "Return a list of all expansions and their usage.
> +Each expansion is a cons cell where the `car' is the expansion
> +and the `cdr' is the number of times the expansion has been
> +typed."

This doc string doesn't explain the meaning of "usage" in this case.

> +Below is a list of expansions for which abbrevs are defined, and
> +the number of times the expansion was typed manually. To display
                                                       ^^
Two spaces between sentences, please.

Finally, I think these new features should be in NEWS and probably
also in the user manual.

Thank you for working on this.