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combinators

Combinators grab-bag.

Documentation

Sort Combinators

group/key

[procedure] (group/key KEYPROC LYST [EQUALITY equal?])

Groups a LYST of elements by some key attribute. Uses the single-argument KEYPROC to retrieve key values & the EQUALITY procedure to compare them.

Returns a list of grouped elements.

make-less-than/key

[procedure] (make-less-than/key KEYPROC [LESS-THAN <])

Returns a two-argument procedure that uses the single-argument KEYPROC to retrieve key values & the two-argument LESS-THAN procedure to compare them.

make-equal/key

[procedure] (make-equal/key KEYPROC [EQUAL =])

Returns a two-argument procedure that uses the single-argument KEYPROC to retrieve key values & the two-argument EQUAL procedure to compare them.

Logical Combinators

andf

[procedure] (andf OBJECT...)

Returns last (not #f) OBJECT when all OBJECT... are (not #f), #f otherwise.

orf

[procedure] (orf OBJECT...)

Returns first (not #f) OBJECT, #f otherwise.

Stack Combinators

C is a combinator function.

F, G and H are function.

X, Y and Z are object.

uni

[procedure] (uni X F C) => OBJECT

Returns the result of (C (F X)).

[procedure] (uni F C) => PROCEDURE/1
[procedure] (uni C) => PROCEDURE/1
[procedure] (uni) => PROCEDURE/1

Returns a curried procedure.

uni2

[procedure] (uni2 X Y F C) => OBJECT

Returns the result of (C (F X Y)).

[procedure] (uni2 F C) => PROCEDURE/2
[procedure] (uni2 C) => PROCEDURE/1
[procedure] (uni2) => PROCEDURE/1

Returns a curried procedure.

uni3

[procedure] (uni3 X Y Z F C) => OBJECT

Returns the result of (C (F X Y Z)).

[procedure] (uni3 F C) => PROCEDURE/3
[procedure] (uni3 C) => PROCEDURE/1
[procedure] (uni3) => PROCEDURE/1

Returns a curried procedure.

bi

[procedure] (bi X F G C) => OBJECT

Returns the result of (C (F X) (G X)).

[procedure] (bi F G C) => PROCEDURE/1
[procedure] (bi F G) => PROCEDURE/1
[procedure] (bi C) => PROCEDURE/2
[procedure] (bi) => PROCEDURE/1

Returns a curried procedure.

bi2

[procedure] (bi2 X Y F G C) => OBJECT

Returns the result of (C (F X Y) (G X Y)).

[procedure] (bi2 F G C) => PROCEDURE/2
[procedure] (bi2 F G) => PROCEDURE/1
[procedure] (bi2 C) => PROCEDURE/2
[procedure] (bi2) => PROCEDURE/1

Returns a curried procedure.

bi3

[procedure] (bi3 X Y Z F G C) => OBJECT

Returns the result of (C (F X Y Z) (G X Y Z)).

[procedure] (bi3 F G C) => PROCEDURE/3
[procedure] (bi3 F G) => PROCEDURE/1
[procedure] (bi3 C) => PROCEDURE/2
[procedure] (bi3) => PROCEDURE/1

Returns a curried procedure.

bi@

[procedure] (bi@ X Y F C) => OBJECT

Returns the result of (C (F X) (F Y)).

[procedure] (bi@ F C) => PROCEDURE/2

Returns a curried procedure.

tri

[procedure] (tri X F G H C) => OBJECT

Returns the result of (C (F X) (G X) (H X)).

[procedure] (tri F G H C) => PROCEDURE/1
[procedure] (tri F G H) => PROCEDURE/1
[procedure] (tri C) => PROCEDURE/3
[procedure] (tri) => PROCEDURE/1

Returns a curried procedure.

tri2

[procedure] (tri2 X Y F G H C) => OBJECT

Returns the result of (C (F X Y) (G X Y) (H X Y)).

[procedure] (tri2 F G H C) => PROCEDURE/2
[procedure] (tri2 F G H) => PROCEDURE/1
[procedure] (tri2 C) => PROCEDURE/3
[procedure] (tri2) => PROCEDURE/1

Returns a curried procedure.

tri3

[procedure] (tri3 X Y Z F G H C) => OBJECT

Returns the result of (C (F X Y Z) (G X Y Z) (H X Y Z)).

[procedure] (tri3 F G H C) => PROCEDURE/3
[procedure] (tri3 F G H) => PROCEDURE/1
[procedure] (tri3 C) => PROCEDURE/3
[procedure] (tri3) => PROCEDURE/1

Returns a curried procedure.

tri@

[procedure] (tri@ X Y Z F G H C) => OBJECT

Returns the result of (C (F X) (G Y) (H Z)).

[procedure] (tri@ F G H C) => PROCEDURE/3

Returns a curried procedure.

dip

[procedure] (dip X Y F C) => OBJECT

Returns the result of (C (F X) Y).

[procedure] (dip F C) => PROCEDURE/2

Returns a curried procedure.

dup

[procedure] (dup X C) => OBJECT

Returns the result of (C X X).

[procedure] (dup C) => PROCEDURE/1

Returns a curried procedure.

dupd

[procedure] (dupd X Y C) => OBJECT

Returns the result of (C X X Y).

[procedure] (dupd C) => PROCEDURE/2

Returns a curried procedure.

swap

[procedure] (swap X Y C) => OBJECT

Returns the result of (C Y X).

[procedure] (swap C) => PROCEDURE/2

Returns a curried procedure.

drop

<procedure>(drop X C)< => OBJECT/procedure>

Returns the result of (C).

[procedure] (drop C) => PROCEDURE/1

Returns a curried procedure.

drop/2

[procedure] (drop/2 X Y C) => OBJECT

Returns the result of (C X).

[procedure] (drop/2 C) => PROCEDURE/2

Returns a curried procedure.

Usage

 
(require-extension logical-combinators)
(require-library logical-combinators)
...
(import logical-combinators)

Examples

 
(group/key identity '(1 2 3 3 4 4 4)) ;=> ((1) (2) (3 3) (4 4 4))

(group/key car '((a 1) (a 2) (b 1)))  ;=> '(((a 1) (a 2)) ((b 1)))

(sort '(("a" . 1) ("z" . 3) ("b" . 2)) (make-less-than/key first string-ci<?)) ;=> (("a" . 1) ("b" . 2) ("z" . 3))

Notes

Requirements

Bugs and Limitations

Author

kon lovett

Version history
1.0.0
Chicken 4 release.

License

Public Domain.