Comment by skydhash

For me it would be like this:

    mixed reduce(function fun, array arr, mixed|void zero) {
      if(sizeof(arr))
        zero = arr[0];

      for(int i=1; i<sizeof(arr); i++)
        zero = ([function(mixed,mixed:mixed)]fun)(zero, arr[i]);

      return zero; 
  }

I only want to isolate blocks (around 10 lines at most) then I can dive in if necessary. I'm using minimal syntax highlighting in Emacs, but I can do fine without.