Scalar::Lazy Yet another lazy evaluation in Perl
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Scalar::Lazy Tags

Perl module perl Scalar evaluation lazy evaluation scalar evaluation

Scalar::Lazy Description

Yet another lazy evaluation in Perl Scalar::Lazy is yet another lazy evaluation in Perl.SYNOPSIS use Scalar::Lazy; my $scalar = lazy { 1 }; print $scalar; # you don't have to force # Y-combinator made easy my $zm = sub { my $f = shift; sub { my $x = shift; lazy { $f->($x->($x)) } }->(sub { my $x = shift; lazy { $f->($x->($x)) } })}; my $fact = $zm->(sub { my $f = shift; sub { my $n = shift; $n < 2 ? 1 : $n * $f->($n - 1) } }); print $fact->(10); # 3628800DISCUSSIONThe classical way to implement lazy evaluation in an eager-evaluating languages (including perl, of course) is to wrap the value with a closure: sub delay{ my $value = shift; sub { $value } } my $l = delay(42);Then evaluate the closure whenever you need it. my $v = $l->();Marking the variable lazy can be easier with prototypes: sub delay(&){ $_ } my $l = delay { 42 }But forcing the value is pain in the neck.This module makes it easier by making the value auto-forcing. Requirements: · Perl

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