Re: Passing expression as a parameter
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- Subject: Re: Passing expression as a parameter
- From: TNHarris <telliamed@...>
- Date: 2013年1月10日 18:15:27 -0500
On Wednesday, January 09, 2013 12:18:16 PM Dirk Laurie wrote:
> Unless `lambda` is used inside a loop that will be executed
> millions of times, the execution penalty compared to
> a patch is negligible.
Which is why you memoize the string.
local lambdacache = {}
lambda = function(def)
local closure,error = lambdacache[def]
if closure then return closure end
local arrow = "%->"
local args,result = def:match("^%s*(.*)"..arrow.."(.*)$")
if not args then return nil,"expected -> in lambda expression" end
if args~="" then args = args.."=... " end
closure,error = load(args.."return "..result)
if closure then lambdacache[def] = closure end
return closure,error
end
Modified to allow lambda"->foo". It should also recursively expand the
expression so you could do lambda"x->y->foo(x,y)"
--
tom <telliamed@whoopdedo.org>