Re: How to implement this with LuaMacro?

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

On Mon, Jan 25, 2010 at 10:04 AM, Pavel Shevaev <pacha.shevaev@gmail.com> wrote:
> Guys, now I'm trying to implement this and it looks like I need
> variable arguments list within a macro. Is it possible at all?

Very much so. Consider this macro:

macro.define ('sum',{handle_parms = macro.parameter_grabber(')',',','(')},
	function(ls,...)
		local args = {...}
		local subst,put = macro.subst_putter()
		local n = #args
		for i = 1,n do
			put(args[i])
			if i < n then put '+' end
		end
		return subst
	end
)

sum(10,20,30) will expand to 10+20+30

Here handle_parms is a function which explicitly expects an arguments
list: start with '(', use ',' as the delimiter, and end with ')'.
This gives you an array of arguments.

The substitution is here a function, which receives an arbitrary
number of arguments and explicitly creates an output token list.

It's more low-level, but one can create anything this way.

steve d.