Context sensitive code highlighting.

Context sensitive code highlighting.

[Robin.Fairey]

How hard would it be to implement context sensitive font lock
behaviour? I'm thinking of something that scans the code for an
argument list and then highlights subsequent occurences of the
argument names in a new colour. This requires adding new keywords to
the highlighter on the fly, determined by content in the file itself
instead of in a keyword list at the beginning of the process. I've
tweaked some other syntax highlighting modes, but I've no idea where
to start with this one. I'm not looking for a full solution, just a
pointer to where to start looking, or something I can read and modify
to my needs?

Re: Context sensitive code highlighting.

[Tassilo Horn]

Robin.Fairey@gmail.com writes:

> How hard would it be to implement context sensitive font lock
> behaviour? I'm thinking of something that scans the code for an
> argument list and then highlights subsequent occurences of the
> argument names in a new colour.

Have a look at highlight-symbol.el [1], especially `highlight-symbol-mode'.

Bye,
Tassilo
__________
[1] http://www.emacswiki.org/cgi-bin/emacs-en/HighlightSymbol
    http://nschum.de/src/emacs/highlight-symbol/

Re: Context sensitive code highlighting.

[Lennart Borgman (gmail)]

Tassilo Horn wrote:
> Robin.Fairey@gmail.com writes:
> 
>> How hard would it be to implement context sensitive font lock
>> behaviour? I'm thinking of something that scans the code for an
>> argument list and then highlights subsequent occurences of the
>> argument names in a new colour.

See

   (info "(elisp) Search-based Fontification")

You can use a function instead of a regexp for searching for things to 
highlight. So it is possible to do what you want. You just need to do 
some book-keeping.

> Have a look at highlight-symbol.el [1], especially `highlight-symbol-mode'.
> 
> Bye,
> Tassilo
> __________
> [1] http://www.emacswiki.org/cgi-bin/emacs-en/HighlightSymbol
>     http://nschum.de/src/emacs/highlight-symbol/


It is very good, but would look much better if a background overlay 
could be used instead in hi-lock.

Re: Context sensitive code highlighting.

[Eric M. Ludlam]

>>> Robin.Fairey@gmail.com seems to think that:
>How hard would it be to implement context sensitive font lock
>behaviour? I'm thinking of something that scans the code for an
>argument list and then highlights subsequent occurences of the
>argument names in a new colour. This requires adding new keywords to
>the highlighter on the fly, determined by content in the file itself
>instead of in a keyword list at the beginning of the process. I've
>tweaked some other syntax highlighting modes, but I've no idea where
>to start with this one. I'm not looking for a full solution, just a
>pointer to where to start looking, or something I can read and modify
>to my needs?

If you have particularly complex context/highlighting needs, in
CEDET/Semantic there is a decoration mode which calls your function
whenever a semantic tag (function, variable, argument, struct field,
etc) is found, and you can then highlight it using any mechanism you
like, though creating the overlays w/ the decoration API makes sure they
are kept up to date.

One sample mode in CEDET puts an overline on top of any function or data
type that is a certain length.

http://cedet.sourceforge.net/

Of course, then your highlighter is dependent on a particularly complex
secondary installation.

Eric