Re: LuaMacro

["steve donovan" <steve.j.donovan@...>]

On Jan 3, 2008 6:06 PM, Eike Decker <eike@cube3d.de> wrote:
> #define printint(x) printf("%s = %i\n",#x,x)

That's a nice example, because it makes adding debug variable writes easier.

In LuaMacro:

macro.define('P",{"arg"},@ print(_STR(arg)..' = '..arg) @)

so

P(alpha)

prints 'alpha = 2'

Very easy to make that go to a logger, etc. And make a simple change
to the macro, and the debug writes don't appear in the 'release'
build.

Other examples abound. For instance, in LuaJava, objects get created like this:

obj = luajava.newInstance("java.lang.Object")

It is not difficult to make a macro 'new' and write this:

obj = new Object

which would be smart enough to know that a unqualifed class name comes
from the 'java.lang' package.

BTW, I am no longer happy with @ .. @ token list literals, so I've put
in a little lexer, so one can use simple quoted strings instead. This
has other useful consequences, apart from reducing the lexical noise
;)

I would hesitate to use macros in code which I'm sharing with the
community. But debug and build support, particularly test frameworks,
can be made more painless.

steve d.