[implementations-list] buggy behaviour with Transient Mark Mode disabled

[Vegard Øye]

> Date: Tue, 13 Apr 2010 17:04:08 +0200
> From: stepnem at gmail.com
>
>> Thank you for the bug report. This should be fixed in revision 203.
>
> Yeah, seems to work fine now, thanks!

Great!

> Yeah, well that's a kind of problem -- TMM mode is supposed to
> highlight the current region, i.e. the portion between point and
> mark. And you can have mark (and region) without TMM, of course --
> it's just not highlighted (or perhaps "active" in TMM-speak), but
> gets highlighted as soon as you enable TMM. Which is perfectly
> correct behaviour.

Transient Mark mode doesn't necessarily hightlight the region; it
creates a distinction between "active regions" and "inactive regions".
By default, the region is inactive; it has to be /made/ active to be
highlighted. When Transient Mark mode is disabled, on the other hand,
there is no distinction; the region is just the region.

Vimpulse wants the distinction between "active" and "inactive",
because it allows it to reliably identify selection commands like
`mark-sexp' and `mark-paragraph', which activate the region in
Transient Mark mode. So, when you press "d M-h", the region is
activated, and that region is deleted. When you press "d w", the
region is not activated, so a motion range is constructed instead, and
that range is deleted.

It's this distinction which makes Transient Mark mode valuable,
although it is a PITA to get the frequent enabling/disabling to work
smoothly.

>> How does one discover these things? Multiple files to the rescue!
>
> Hm... I'd say that's a rather crude way of debugging; I wouldn't
> consider that a persuasive argument for multiple files (also see
> below).

Crude? Hell yeah. But that's the problem with poorly documented global
variables: you have no idea /what/ might be influencing them. It would
never occur to me that `push-mark' changes `mark-active' when
Transient Mark mode is /disabled/ -- and, furthermore, that
C-SPC (`set-mark-command') overrides this behavior by calling
`deactivate-mark'!

Of course, I rarely debug in this way. Most of the bugs are of my own
making, they can be /seen/ with edebug, and usually I have some idea
about where they may be.

> You don't even need multiple files for your debugging method. You
> can unload the features one by one anyway (the only difference being
> `vimpulse' depending on all the others, so you would need to unload
> it first or use the FORCE argument to `unload-feature').

Hm. Wouldn't requiring any single feature load the whole file?

> Yeah... not easier, it would be a PITA for both searching and editing,
> so I wanted to avoid that.

M-x lgrep :)

Vegard 		 	   		  
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