Re: Evolutionary User Strategy - A Compromise

[Erik Sandberg]

On Wednesday 12 July 2006 22:25, Graham Percival wrote:
> Erik Sandberg wrote:
> > There's also the question of what you mean by compatibility: Very
> > advanced tweaks usually rely on the way lily's internals are organised,
> > which may change over time. Since lily contains a Turing-complete
> > programming language, for some language updates it is thereby
> > _impossible_ to create a script that upgrades _all_ .ly files perfectly.
>
> Actually, doesn't this mean that we can _always_ upgrade _all_ .ly files
> perfectly?  Since lily contains a Turing-complete language, we just need
> to write a universal Turing machine which emulates the behavior of 2.4
> (or whatever).  Then convert-ly takes 2.4, adds our Turing machine, and
> presto, we have a .ly file which compiles under 2.8.
>
> Of course, that .ly file is probably about 20 megabytes in size, and
> would take a huge amount of time to run... but it would work!  :)

Yes, true :) another way would be to let the convert-ly script compile the old 
file into an EPS, which is embedded directly into the ly file. The drawback 
with this approach is that convert-ly will hang on broken ly files.

-- 
Erik