Re: Understanding Word and Sentence Boundaries

[Eric Abrahamsen]

ken <gebser@mousecar.com> writes:

> On 06/26/2010 11:05 PM Deniz Dogan wrote:
>> 2010/6/27 ken<gebser@mousecar.com>:
>>>
>>> On 06/26/2010 06:53 AM Paul Drummond wrote:
>>>> Thanks for the responses guys.
>>>>
>>>> I think the point I am trying to make here is that it's a *big* task to
>>>> fix word boundaries for every case (every word-related key binding
>>>> multiplied by each language/major mode I use!).
>>>>
>>>> I presume that Emacs hackers either a) put up with it or b) spend a lot
>>>> of time fixing each case until they are happy.
>>>>
>>>> I suspect the answer is b. ;-)
>>>>
>>>> I wish there was a single minor-mode that fixes all the word boundary
>>>> issues for every major-mode I use!  I can but dream.   Or maybe I will
>>>> get round to doing it myself one day!  ;)
>>>>
>>>> Cheers,
>>>> Paul Drummond
>>>
>>>
>>> Is it possible to specify word boundaries for a particular mode?
>>>
>>
>> Yes, it's part of the syntax table. See e.g. `modify-syntax-entry'.
>
> Thanks for the pointer to that function.
>
> The behavior I see in need of repair is the role of so-called "comments"
> in sentence syntax.</tag>  For instance, immediately before this
> sentence are two spaces... which should signify the end of the
> previous sentence.  But functions like "forward-sentence" and
> "fill-paragraph" and "backward-sentence" don't recognize it.
>
> Said another way, the "</tag>" string obscures the relationship
> between the period before it and the two spaces after it and so fails
> to see that one sentence ends and another starts.  This occurs in
> text-mode and seems to be inherited by other modes.
>
> If I'm reading "modify-syntax-entry" correctly, the default meanings
> of '<' and '>' are, respectively, beginning and end of comment, so
> modifying them wouldn't fix this problem.  Or can this be remedied by
> a change in the syntax table?  Or is this a bug?

For this particular case, I think you can modify the value of the
`sentence-end' variable (which is returned by the `sentence-end'
function? The whole thing is a little confusing). You'd probably be best
off starting with the docstring for the sentence-end function, and
working back from there.

I think the `sentence-end' variable is automatically buffer-local, which
means if you change it in a mode-hook it ought to work the way you want.
I agree that the whole syntax thing feels like a very well-polished
hack.

E