Rewrite chord symbol input and output

[Nick Fletcher]

Hi,

The chord symbol input and output system on Lilypond is driving me nuts - does
anyone know of a convenient way to rewrite it from scratch so that....

1) It knows what I mean when I input, e.g. "c:alt7", i.e. c,e,gis,bes,dis
2) It knows to display this chord as "C7alt", or whatever.

I'm aware that what I'm asking for sounds a bit drastic but I've tried using the
chord exceptions system but I can't get it to do what I want. What I'd like to
be able to do is simply define inputs and outputs as above.

Cheers
Nick