Just another update

Task/Fibonacci-sequence/Perl/fibonacci-sequence-1.pl

@@ -1,32 +1,7 @@
-# Iterative Fibonacci with bignum support.
-# Multi-licensed under your choice of:
-# 1. The GNU Free Documentation License (GFDL).
-# 2. The MIT/X11 license.
-# 3. The GNU General Publice License (GPL).
-# 4. The Public Domain as understood by the CC-Zero public domain dedication.
-
-use strict;
-use warnings;
-
-use Math::BigInt try => 'GMP';
-
-sub fib_iter
-{
-    my ($n) = @_;
-
-    my $this_fib = Math::BigInt->new(0);
-    my $next_fib = Math::BigInt->new(1);
-
-    my $pos = 0;
-
-    while ($pos < $n)
-    {
-        ($this_fib, $next_fib) = ($next_fib, $this_fib+$next_fib);
-    }
-    continue
-    {
-        $pos++;
-    }
-
-    return $this_fib;
+sub fib_iter {
+  my $n = shift;
+  use bigint try => "GMP,Pari";
+  my ($v2,$v1) = (-1,1);
+  ($v2,$v1) = ($v1,$v2+$v1) for 0..$n;
+  $v1;
 }

Task/Fibonacci-sequence/Perl/fibonacci-sequence-3.pl

@@ -0,0 +1,20 @@
+# Binary ladder, GMP if available, Pure Perl otherwise
+use ntheory qw/lucasu/;
+say lucasu(1, -1, 10000);
+
+# Uses GMP internal method, so similar performance as above
+use Math::GMP;
+say Math::GMP::fibonacci(10000);
+
+# All Perl
+use Math::NumSeq::Fibonacci;
+my $seq = Math::NumSeq::Fibonacci->new;
+say $seq->ith(10000);
+
+# All Perl
+use Math::Big qw/fibonacci/;
+say 0+fibonacci(10000);  # Force scalar context
+
+# Perl, gives floating point *approximation*
+use Math::Fibonacci qw/term/;
+say term(10000);