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Source for wiki CombinatorsCowan version 1

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cowan

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69.195.55.172

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CombinatorsCowan

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This proposal contains various procedures that return procedures and a few others, drawn from Chicken.  Common Lisp has a few of them too.

`(always `''obj''`)`

Ignores its argument and always returns `#t`. 

`(constantly `''obj'' ...`)`

Returns a procedure that always returns the ''obj'' objects as its values, regardless of the number and value of its arguments.

`(complement `''proc''`)`

Returns a procedure that returns the boolean inverse of ''proc''.

`(compose `''proc'' ... `)`

Returns a procedure that represents the composition of its arguments.  Any of the procedures may return multiple values, which are passed as arguments to its successor.  With zero arguments, `(compose)` returns a procedure that is functionally equivalent to `values`.

`(conjoin `''predicate'' ...`)`

Returns a procedure that returns `#t` if its argument satisfies all the ''predicate''s.

`(disjoin `''predicate'' ...`)`

Returns a procedure that returns `#t` if its argument satisfies any of the ''predicate''s.

`(each `''proc'' ... `)`

Returns a procedure that applies each of the ''proc''s in turn to its arguments, discarding the results and returning an unspecified value.

`(flip `''proc''`)`

Returns a two-argument procedure that calls ''proc'', a two-argument procedure, with its arguments swapped.

`(identity `''obj''`)`

Returns ''obj''.

`(list-of? `''predicate''`)`

Returns a procedure of one argument that returns `#t` when applied to a list of elements that all satisfy ''predicate'', or `#f` otherwise.

`(never `''obj''`)`

Ignores its argument and always returns `#f`.

`(o `''proc'' ...`)`

A variant of `compose` that does not handle multiple-valued procedures. With zero arguments, returns a procedure that is functionally equivalent to `identity`.

time

2012-11-23 13:45:08