Re: Features you would like to see

[Niklas Frykholm <niklas@...>]

Thomas Breuel wrote:
> Scheme is a great language--a language designed for computer 
> scientists and experienced programmers to play around with new ideas.  
> Lua is a widely used extension language for general users.  Once 
> macros are available in a programming language, readers can tell much 
> less about what a piece of code does than if macros are not available.
>
> Most uses of macros can be handled more cleanly with a compact lambda 
> or block construct, plus some simple operators.  I think Lua already 
> has pretty good support for that, but maybe a more Smalltalk/Ruby-like 
> block syntax could improve things a little further.
As someone using Lua in a performance-aware environment I'm interested 
in macros, not so much for the ability of redefining the core language, 
but for the possible performance improvements, such as conditional 
compilation of debug-statements:

   function f()
      debug("This should disappear in release compiles.")
      ...
   end

I agree that lambdas can do most of what macros can do, but they fall 
short in terms of performance. It would be really good to be able to add 
debug statements, parameter checking, asserts, etc... and know that we 
only payed the cost of those in our debug builds.

I've considered pairing Lua with some external macro language, but the C 
preprocessor feels to C specific and I don't like the syntax of M4. I 
think the macro language would need to be lua-aware to have decent 
syntax. And the best of all would be hygienic macros with Lua itself as 
the macro language.

-- Niklas