Re: Recursion, Yo

On 09/04/2024 09:43, Lawrence D'Oliveiro wrote:

On Tue, 9 Apr 2024 10:25:46 +0200, Janis Papanagnou wrote:
 

If folks learned coding from imperative languages they have more
problems with a functional view (and also with recursion, it seems).

 One of the first few books I ever read on Comp Sci (while still at school,
back when schools didn’t have computers) was “A Comparative Study Of
Programming Languages” by Bryan Higman. In one of the chapters, I came
across the concept of recursion. I also came across Ackermann’s Function.
 Let’s just say that, after staring into that abyss, nothing about
recursion could possibly scare me, ever again ...

This one is a bit scarier:
   https://en.wikipedia.org/wiki/Man_or_boy_test
Although normally requiring closures, there are many implementations here that work around that, including for C:
   https://rosettacode.org/wiki/Man_or_boy_test
There is also a C version that relies on gcc's (gnuC) extensions for nested function, but when I tested it, it was nearly 200 times slower than plain C.