Accumulator factory: Difference between revisions

=={{header|Lang}}==

Lang does not support closures. The use of combinator functions and pointers allows a function to store state.

<syntaxhighlight lang="lang">

fp.accumulator = ($sum) -> {

$sumPtr = $[sum]

fp.f = ($sumPtr, $n) -> {

$*sumPtr += $n

return $*sumPtr

}

return fn.argCnt1(fn.combA2(fp.f, $sumPtr))

}

$x = fp.accumulator(1)

fn.println($x(5))

fp.accumulator(3)

fn.println($x(2.3))

fn.println()

$y = fp.accumulator(1.)

fn.println($y(5))

fn.println($y(2.3))

</syntaxhighlight>

{{out}}

<pre>

6

8.3

6.0

8.3

</pre>