combinators

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Combinators grab-bag.

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combinators
Documentation
- Section Combinators
- Sort Combinators
- Logical Combinators
  - Usage
  - andf
  - orf
- Uni Combinators
  - Usage
  - uni
  - uni2
  - uni3
  - uni-each
  - uni-all
- Bi Combinators
  - Usage
  - bi
  - bi2
  - bi3
  - bi-each
  - bi-all
- Tri Combinators
  - Usage
  - tri
  - tri2
  - tri3
  - tri-each
  - tri-all
- Stack Combinators
  - Usage
  - uni
  - uni2
  - uni3
  - uni@
  - bi
  - bi2
  - bi3
  - bi@
  - tri
  - tri2
  - tri3
  - tri@
  - dip
  - dup
  - dupd
  - swap
  - drop
  - drop/2
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Documentation

Section Combinators

Usage

(require-extension section-combinators)

FUNC a procedure.

left-section

left-section FUNC ARG0 ...procedure

Returns a procedure that partially applies some of its arguments from the left.

ARG0 ... a prefix of the arguments for FUNC.

Returns a partially curried procedure.

right-section

right-section FUNC ARG0 ...procedure

Returns a procedure that partially applies some of its arguments from the right.

ARG0 ... a suffix of the arguments for FUNC.

Returns a partially curried procedure.

crop-left

crop-left FUNC Nprocedure: Returns a procedure that drops the N left arguments before applying FUNC.

crop-right

crop-right FUNC Nprocedure: Returns a procedure that drops the N right arguments before applying FUNC.

reversed

reversed FUNCprocedure: Returns a procedure that reverses the arguments before applying FUNC.

arguments-chain

arguments-chain #!optional FUNC0...procedure

Returns a procedure that applies each FUNCi to result of the FUNCi+1. FUNCn is applied to the arguments.

Examples:

((arguments-chain f g h) arg...) -> (apply f (apply g (apply h arg...)))

((arguments-chain f) arg...) -> (apply f arg...)

((arguments-chain) arg...) -> (list arg...)

arguments-each

arguments-each #!optional FUNC0...procedure

Returns a procedure that calls each FUNCi to the ARGi. The result is returned as a list. The FUNC0... are re-used until the argument list is exhausted.

Examples:

((arguments-each f g h) a b c d e) -> (list (f a) (g b) (h c) (f d) (g e))

((arguments-each f g h) a b c) -> (list (f a) (g b) (h c))

((arguments-each) arg...) -> (list arg...)

arguments-all

arguments-all #!optional FUNC0...procedure

Returns a procedure that calls each FUNCi with all the arguments. The result is returned as a list.

Examples:

((arguments-all f g h) a b c) -> (list (f a b c) (g a b c) (h a b c))

((arguments-all) arg...) -> (list arg...)

Sort Combinators

Except for make-less-than/key and make-equal/key these are not combinators.

Usage

(require-extension sort-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))

group-by

(group-by FUNC [EQUALITY equal?]) => procedureprocedure: Returns a procedure that takes a list and groups the elements by some key attribute. Uses the single-argument FUNC to retrieve key values & the EQUALITY function to compare them.

group/key

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

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

The LYST must be in sorted order with respect to the key!

Returns a list of grouped elements.

make-less-than/key

(make-less-than/key FUNC [LESS-THAN <]) => {{procedure/2}}procedure: Returns a two-argument procedure that uses the single-argument FUNC to retrieve key values & the two-argument LESS-THAN procedure to compare them.

make-equal/key

(make-equal/key FUNC [EQUAL =]) => {{procedure/2}}procedure: Returns a two-argument procedure that uses the single-argument FUNC to retrieve key values & the two-argument EQUAL procedure to compare them.