Re: my-calculate-indent function

[Tim X <timx@nospam.dev.null>]

Pietro Giorgianni <giorgian@gmail.com> writes:

> hi,
>
> i'm working on a major mode for a simple script language.
>
> blocks are enclosed in {}, and i wrote this function:
>
> (defun tintin-calculate-indent ()
>   (let ((opened (count-matches "{" 0 (point)))
>         (closed (count-matches "}" 0 (point))))
>     (max 0
>      (if (equal (char-after) 125)
>          (* tintin-indentation-step (- (- opened closed) 1))
>        (* tintin-indentation-step (- opened closed))))))
>
>
> which works, but is ugly.
>
> questions:
>
> 1) is there already a function that does this?
>
> 2) if not, how can i do it better?
>

I had a similar experience and decided to use some of the built-in syntax
parsing functions. For these to work, you will probably have to tweak the
syntax table entries, but this isn't hard and will probably help with
font-locking as well. In particular, see the sections on syntax tables and
parsing in the emacs lisp reference. the function syntax-ppss was particularly
useful for me.

,----[ C-h f syntax-ppss RET ]
| syntax-ppss is a compiled Lisp function in `syntax.el'.
| (syntax-ppss &optional POS)
| 
| Parse-Partial-Sexp State at POS.
| The returned value is the same as `parse-partial-sexp' except that
| the 2nd and 6th values of the returned state cannot be relied upon.
| Point is at POS when this function returns.
`----


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