Closures/Value capture: Difference between revisions

=={{header|Lingo}}==

Lingo doesn't really support closures. But with the limitations described at [https://www.rosettacode.org/wiki/Function_composition#Lingo Function composition] and based on the fact that Lingo allows to create arbitrary code at runtime, the task can be solved like this:

<lang lingo>-- parent script "CallFunction"

property _code

on new (me, code)

me._code = code

return me

end

on call (me)

----------------------------------------

-- If custom arguments were passed, evaluate them in the current context.

-- Note: in the code passed to the constructor they have to be specied as

-- arg[1], arg[2], ...

arg = []

repeat with i = 3 to the paramCount

arg[i-2] = param(i)

end repeat

----------------------------------------

res = VOID

do(me._code)

return res

end</lang>

<lang lingo>funcs = []

repeat with i = 1 to 10

code = "res="&i&"*"&i

funcs[i] = script("CallFunction").new(code)

end repeat

put call(funcs[3], _movie)

-- 9</lang>

Since the original task is a little trivial in terms of not depending on runtime arguments, here also a solution for an extended task: let each function[i] return the square of i plus the sum of all arguments passed to it at runtime:

<lang lingo>funcs = []

repeat with i = 1 to 10

code = ""

put "res = "&i&"*"&i &RETURN after code

put "repeat with i = 1 to arg.count" &RETURN after code

put " res = res + arg[i]" &RETURN after code

put "end repeat" &RETURN after code

funcs[i] = script("CallFunction").new(code)

end repeat

put call(funcs[3], _movie, 23)

-- 32

put call(funcs[7], _movie, 4, 5, 6)

-- 64</lang>