clj-arrow is a small library for combining functions.
In leiningen add
[clj-arrow "1.0.3-SNAPSHOT"] to dependencies. Otherwise, put the
on the classpath. Only clojure is required as a dependency.
Usage and installation
require clj-arrow.arrow. In this namespace these functions exist (see docstrings for usage):
functions creating functions
>>>- create a flow of functions to the right.
<<<- create a flow of functions to the left.
fst- apply a function to the first value of a pair.
snd- apply a function to the second value of a pair.
***- apply two functions to respective values of a pair.
&&&- same as
***, but takes a single value which is cloned to a pair.
ifconditional statement for functions.
***-multithread- same as
&&&-multithread- same as
&&&-multithread work can be done in parallel.
(time ((&&& #(Thread/sleep %) #(Thread/sleep %)) 1000)) ; "Elapsed time: 2006.765373 msecs" ;=> [nil nil] (time ((&&&-multithread #(Thread/sleep %) #(Thread/sleep %)) 1000)) ; "Elapsed time: 1004.629826 msecs" ;=> [nil nil]
Functions and arrows
While I only mention functions as arguments to the functions above, they could be used just as well with any type of arrow (functions can be seen as a subset of arrows).
What is an arrow?
This is a delicate subject, which I must admit that I don't quite understand myself.
However, for clj-arrow it's simple: any /thing/ (class, record ...) implementing
clj-arrow.arrow/Arrow protocol (or the underlying interface) is an arrow. The protocol defines the following functions:
run- function to execute the arrow.
>>>_int- the arrow's implementation of
>>>, takes only two arguments.
fst_int- the arrow's implementation of
An arrow implementing these functions must also not make any assumptions of what type of arrow is sent as the second argument to the
If these conditions are met, the arrow will work with all the functions described in Usage.
Copyright (c) 2011 Jonathan Fischer Friberg
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