NAME
    Scalar::Defer - Calculate values on demand

SYNOPSIS
        use Scalar::Defer; # exports 'defer' and 'lazy'

        my ($x, $y);
        my $dv = defer { ++$x };    # a defer-value (not memoized)
        my $lv = lazy { ++$y };     # a lazy-value (memoized)

        print "$dv $dv $dv"; # 1 2 3
        print "$lv $lv $lv"; # 1 1 1

DESCRIPTION
    This module exports two functions, "defer" and "lazy", for building
    values that are evaluated on demand.

  defer {...}
    Takes a block or a code reference, and returns an overloaded value. Each
    time that value is demanded, the block is evaluated again to yield a
    fresh result.

  lazy {...}
    Like "defer", except the value is computed at most once. Subsequent
    evaluation will simply use the cached result.

NOTES
    Unlike the "tie"-based Data::Lazy, this module operates on *values*, not
    *variables*. Therefore, assigning into $dv and $lv above will simply
    replace the value, instead of triggering a "STORE" method call.

    Also, thanks to the "overload"-based implementation, this module is
    about 2x faster than Data::Lazy.

AUTHORS
    Audrey Tang <cpan@audreyt.org>

COPYRIGHT (The "MIT" License)
    Copyright 2006 by Audrey Tang <cpan@audreyt.org>.

    Permission is hereby granted, free of charge, to any person obtaining a
    copy of this software and associated documentation files (the
    "Software"), to deal in the Software without restriction, including
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    permit persons to whom the Software is fur- nished to do so, subject to
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    The above copyright notice and this permission notice shall be included
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    THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
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