Hello, protist.
This is second time I saw the name 'High Order Perl'. It took me much time to remember the days with common lisp, but I tried anyway. I wonder what does mit classes uses for lisp? It seems different from common lisp...
Tested with clisp.
(defun sum_from_to(TERM from NEXT to)
(IF (> from to)
0
(+ (funcall TERM from)
(sum_from_to
TERM
(funcall NEXT from)
NEXT
to))))
(defun addone (c) (+ 1 c))
(defun self(x) x)
(defun square (A) (* A A))
(defun sum-int (A B)
(sum_from_to #'self A #'addone B))
(defun sum-sq(A B)
(sum_from_to #'square A #'addone B))
(print (sum-int 3 5))
(print (sum-sq 3 5))
And exact same migration from list to perl would work.
#!/usr/bin/perl
use strict; use warnings; use feature qw(say);
sub sum_from_to{
my ($TERM, $from, $NEXT, $to)=@_;
if( $from > $to ){
0;
} else {
$TERM->($from)
+
sum_from_to(
$TERM,
$NEXT->($from),
$NEXT,
$to
);
}
}
sub addone{ return 1 + $_[0]}
sub self{ return $_[0]}
sub square{ return $_[0] * $_[0]}
sub sum_int {
my($A,$B)=@_;
sum_from_to( \&self, $A, \&addone, $B);
}
sub sum_sq {
my($A,$B)=@_;
sum_from_to( \&square, $A, \&addone, $B);
}
say sum_int(3,5);
say sum_sq(3,5);
regards.