Re: follow-link in grep buffer

[David Kastrup <dak@gnu.org>]

storm@cua.dk (Kim F. Storm) writes:

> Stefan Monnier <monnier@iro.umontreal.ca> writes:
>
>> I vote to change mouse-1-click-follows-link to `double'.
>
> The whole point of mouse-1-click-follows-link is to make emacs behave
> like most other (modern) applications. 
>
> Double click to follow a link is not modern!

This is a misstatement of the goal.  The problem we are addressing in
the first place is that mouse-2 to follow anything is neither modern
nor oldfashioned elsewhere, but completely uncustomary.

Now the "modern" way is to follow links/buttons with a single click,
and I say that we should provide for this in the manner you did: with
an explicit link property enabling this redirection of the otherwise
mouse-2 behavior.

However, for following "easter eggs", namely causing an action where
an action is not usual, like in editing buffers, double clicks are
still quite common.  For those, I would recommend _not_ to set a link
property, but _still_ redirect a double-click to the mouse-2 behavior,
in a similar manner to what your first proposal was.

I would recommend not making any behavior by default dependent on the
single-click length, nor on the focus situation: both approaches are
completely obfuscate and confusing.

So the change to 21.4 behavior would be the following:

a) a double-click on a location that has no double-click binding, but
   a local mouse-2 binding, will execute the mouse-2 binding.  This
   will make double-clicks, where not overriden, follow links without
   further code changes compared to 21.4
b) setting an explicit link property will _additionally_ remap mouse-1
   to mouse-2.  I would not by default make this dependent on anything
   else.

It is obvious from this description that making a larger text area
have an explicit link property would be a mistake, as you would then
get into difficulties positioning the cursor.  As long as only short
buttons and links are concerned, it is tolerably easy and logical to
click before or after the button/link, and then move into it.  The
possibility of a small drag remains for the experienced user.

So grep should not set the link property in my opinion in this scheme,
and gnus should set it sparingly: on MIME buttons it generates itself,
but not on header lines or things looking like a link in the article
text.

> If we have specific problems in certain modes, let's fix those modes
> (e.g. in grep that you have to click on the file:line part of a line
> to jump).

That again requires cleverness.  I don't mind if we have customization
options for this sort of thing, but it is a mistake for the default.

I have a demonstration and workshop for Emacs coming up in the next
two weeks, where I want to tell people to use Emacs for their serious
editing needs.

Telling them "use mouse-2" has always been sort of embarrassing.
Telling them "use mouse-1, but don't press it longer than 200
milliseconds if you want to follow the link, and it won't work if you
have not the focus" will kill the "Emacs is usable for common human"
proposition dead.  Telling people "double click to follow some
possible cross connection" will make them feel at home.

-- 
David Kastrup, Kriemhildstr. 15, 44793 Bochum