Re: Passing expression as a parameter

[TNHarris <telliamed@...>]

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>