Continued fraction: Difference between revisions
→{{header|Perl}}: using persistent private variables
(→{{header|Perl}}: shortening a bit + computing 2*pi instead of pi to make things less boring) |
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=={{header|Perl}}==
{{trans|Perl6}}
Perl5 does not really support lazy lists
With a recent version of Perl (5.10 or above), we can also use persistent private variables (see perlsub). We just need to declare this with the 'use feature "state"' pragma.
In this example we'll show both methods.
<lang perl>sub continued_fraction {
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}
# using closures
printf "√2 ≈ %.9f\n", continued_fraction do { my $n; sub { $n++ ? 2 : 1 } }, sub { 1 };
printf "e ≈ %.9f\n", continued_fraction do { my $n; sub { $n++ ? $n-1 : 2 } }, do { my $n; sub { $n++ ? $n-1 : 1 } };▼
# using persistent private variables
printf "τ ≈ %.9f\n", continued_fraction sub { 6 }, do { my $n; sub { $n++ ? (2*$n - 1)**2 : 2 } }, 1_000;▼
use feature 'state'
▲printf "e ≈ %.9f\n", continued_fraction
▲printf "τ ≈ %.9f\n", continued_fraction sub { 6 },
</lang>
{{out}}
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