annotate general/funutils/fold.m @ 9:45aaf9b2d7b0
Moved high-order sequence/list functions to @cell class.
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samer |
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Mon, 14 Jan 2013 15:49:04 +0000 |
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1 function X=fold(fn,x)
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2 % fold - polypmorphic Fold combinator
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3 %
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4 % fold :: (X,X->X), Type(A) -> X :- sequence_class(Type).
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5 %
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6 % This function applies an associative operator to a list of arguments,
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7 % as if the list was written out with the operator between consecutive
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8 % elements, eg fold(@plus,{1,2,3,4}) = 1+2+3+4.
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9 %
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10 % Works for any sequence class that has head and next methods,
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11 % including seq(A) and cells(A).
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12
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13 if isempty(x), X=[]; else X=foldl(fn,head(x),next(x)); end
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