Paste: my-binary-reduce

Author:	jwmerrill
Mode:	factor
Date:	Fri, 12 Dec 2008 06:10:15

Plain Text |

USING: kernel sequences locals ;
IN: my-sequences

:: (my-binary-reduce) ( seq quot -- val )
    seq length 1 =
    [ seq first ]
    [ seq halves [ quot (my-binary-reduce) ] bi@ quot call ]
    if ; inline recursive
    
: my-binary-reduce ( seq id quot -- val )
    swapd [ (my-binary-reduce) ] keep call ; inline

Annotation: previous version fails on empty sequence

Author:	jwmerrill
Mode:	factor
Date:	Fri, 12 Dec 2008 06:36:22

Plain Text |

USING: kernel sequences locals ;
IN: my-sequences

! Not safe.  Must not be called with the empty sequence
:: (my-binary-reduce) ( seq quot -- val )
    seq length 1 =
    [ seq first ]
    [ seq halves [ quot (my-binary-reduce) ] bi@ quot call ]
    if ; inline recursive
    
: my-binary-reduce ( seq id quot -- val )
    swapd over length 0 = 
    [ 2drop ]
    [ [ (my-binary-reduce) ] keep call ]
    if ; inline

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