Re: What's up with token filters (Re: New operators?)

[Luiz Henrique de Figueiredo <lhf@...>]

> I can see the problems arising from a module that relies on some  
> token-modded behaviour, but such modules should just not be made. I  
> think this isn't a problem in the generic sense; people would use  
> token filters for small syntax "enhancements" easying the application  
> level work they do, knowing which ones they load in _their_  
> environment. Modules and redistributable code should use plain Lua only.

Another way to see this is that applications can distribute precompiled
scripts that depended on token filters without problems. So, the
application scripters can use syntax that is better suited to their
world, but this never shows up when the scripts are executed. The point
of introducing Lua filters was to allow people to experiment with
syntactical changes without having to delve into the innards of Lua.

Of course, for this to happen, support for loading and running filters
needs to be added to luac. On the other hand, only the llex.c used to
build luac needs to be token-filter aware.

Roberto's point should not be taken lightly. Being able to change syntax
easily does has a disruptive potential. On the other hand it is consistent
with Lua's philosophy of proving mechanisms, not features...
--lhf