49 lines
636 B
ReStructuredText
49 lines
636 B
ReStructuredText
--------------
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select
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^^^^^^^^
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Basis Function Combinator
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Use a Boolean value to select one of two items from a sequence.
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::
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[A B] false select
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------------------------
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A
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[A B] true select
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-----------------------
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B
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The sequence can contain more than two items but not fewer.
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Currently Python semantics are used to evaluate the "truthiness" of the
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Boolean value (so empty string, zero, etc. are counted as false, etc.)
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Gentzen diagram.
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Definition
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~~~~~~~~~~
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if not basis.
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Derivation
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~~~~~~~~~~
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if not basis.
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Source
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~~~~~~~~~~
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if basis
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Discussion
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~~~~~~~~~~
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Crosslinks
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~~~~~~~~~~
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