Catamorphism: Difference between revisions

=={{header|BCPL}}==

<lang bcpl>get "libhdr"

let reduce(f, v, len, seed) =

len = 0 -> seed,

reduce(f, v+1, len-1, f(!v, seed))

let start() be

$( let add(x, y) = x+y

let mul(x, y) = x*y

let nums = table 1,2,3,4,5,6,7

writef("%N*N", reduce(add, nums, 7, 0))

writef("%N*N", reduce(mul, nums, 7, 1))

$)</lang>

{{out}}

<pre>28

5040</pre>