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[[tags: egg]]

== pipes

[[toc:]]

=== Description

Besides the documentation procedure, this module exports three routines,
the macros pipe and pipe* as well as the procedure flip*. The first
macro takes a variable and a sequence of partial combinations, calls the
first combination with the variable as additional left argument and
hands the result successively to the next combination. For example

(pipe 3 (+ 1) (- 2) (* 5))

will return 10.

Sometimes its necessary to add the variable to the right of the argument
list. To achieve this simply replace the combination's name, fn say, with
(flip* fn): flip* flips the first argument of fn to the end, and thus is a
generalisation of flip in (chicken base).

==== pipes

<procedure>(pipes)</procedure>
<procedure>(pipes sym)</procedure>

documentation procedure:
the first call shows the list of exported symbols,
the second the documentation of sym.

==== pipe

calls each combination with the result of applying its combination to
the left as first argument. In particular (pipe x (fn . xs)) is
(fn x . xs) and (pipe x (fn . xs) (gn . ys)) is (gn (fn x . xs)).

==== pipe*

pipe as a procedure: (pipe* (fn . xs) ...) is
(lambda (x) (pipe x (fn . xs) ...))

==== flip*

flips the arguments of proc by shifting the first one to the end.

=== Examples

((flip* list)) ; -> '()
((flip* list) 1) ; -> '(1)
((flip* list) 1 2) ; -> '(2 1)
((flip* list) 1 2 3 4) ; -> '(2 3 4 1)
((flip* map) '(0 1 2) add1) ; -> '(1 2 3)

(pipe 5) ; -> 5
(pipe 5 (+ 1)) ; -> 6
(pipe 5 (- 10) (positive?)) ; -> #f
(pipe 5 (- 10) (negative?)) ; -> #t
(pipe 10 ((flip* list) 1 2 3 4)) ; -> '(1 2 3 4 10)
(pipe 10 (list 1 2 3 4)) ; -> '(10 1 2 3 4))
(pipe '(0 1 2) ((flip* map) add1)) ; -> '(1 2 3))
(pipe 0 (list 1 2 3)) ; - > '(0 1 2 3)) 
(pipe 0 ((flip* list) 1 2 3)) ; - > '(1 2 3 0))

</enscript>

=== Requirements

none

== Last update

Mar 28, 2019

== Author

[[/users/juergen-lorenz|Juergen Lorenz]]

== Repository

This egg is hosted on the CHICKEN Subversion repository:

[[https://anonymous@code.call-cc.org/svn/chicken-eggs/release/5/pipes|https://anonymous@code.call-cc.org/svn/chicken-eggs/release/5/pipes]]

If you want to check out the source code repository of this egg and
you are not familiar with Subversion, see [[/egg-svn-checkout|this page]].

== License

Redistribution and use in source and binary forms, with or without
 modification, are permitted provided that the following conditions are
 met:
 
 Redistributions of source code must retain the above copyright
 notice, this list of conditions and the following disclaimer.
 
 Redistributions in binary form must reproduce the above copyright
 notice, this list of conditions and the following disclaimer in the
 documentation and/or other materials provided with the distribution.
 Neither the name of the author nor the names of its contributors may be
 used to endorse or promote products derived from this software without
 specific prior written permission. 
   
 THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS
 IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
 TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
 PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
 HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED
 TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
 PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
 LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
 NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
 SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

== Version History
; 1.0 : initial import

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