Re: Text property searching

[Alan Mackenzie <acm@muc.de>]

Hello, Lars.

On Mon, Apr 16, 2018 at 21:49:11 +0200, Lars Ingebrigtsen wrote:
> Alan Mackenzie <acm@muc.de> writes:

> > Very much so.  If there is a category text property at some point, and
> > the symbol it uses has a foo property, that will normally get seen by
> > the text property primitives.  However, if you put a foo text property
> > there with a nil value, that nil value will mask the intent of the
> > category property.

> Hm.  I am completely unfamiliar with the category stuff -- how is this
> used in practice?

I don't really know, in general.

In C++ and Java Modes, < and > which are template/generic delimiters are
given category text properties, symbols foo and bar, whose syntax-table
properties gives the < and > parenthesis syntax.  This parenthesis syntax
is regularly "switched off" on all such characters simply by changing
the value of foo's and bar's syntax-table properties to punctuation.
This enables syntactic searching where template/generic < and > need not
to be seen.

Having implemented this, I don't recommend the technique.  It has
disadvantages, in that it collides with syntax-ppss.  To be fair, Stefan
advised me not to go ahead with it at an early stage.  I'll probably
remove it from CC Mode at some stage.

> -- 
> (domestic pets only, the antidote for overdose, milk.)
>    bloggy blog: http://lars.ingebrigtsen.no

-- 
Alan Mackenzie (Nuremberg, Germany).