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clarkema/State closures

Created March 6, 2016 14:54
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  1. clarkema created this gist Mar 6, 2016.
    25 changes: 25 additions & 0 deletions State closures
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    Original file line number Diff line number Diff line change
    @@ -0,0 +1,25 @@
    ;; Lisp

    (defun counter ()
    (let ((i 0))
    (lambda () (incf i))))

    (setf indexer (counter))

    (funcall indexer) => 1
    (funcall indexer) => 2
    (funcall indexer) => 3

    # Perl

    sub counter {
    my $i = 0;
    return sub {++$i};
    }

    my $indexer = counter();
    print $indexer->(); # 1
    print $indexer->(); # 2
    print $indexer->(); # 3