pipe
lib.pipe
Docs pulled from | This Revision | about 2 hours ago
Pipes a value through a list of functions, left to right.
Inputs
value-
Value to start piping.
fns-
List of functions to apply sequentially.
Type
pipe :: a -> [<functions>] -> <return type of last function>
Examples
lib.trivial.pipe usage example
pipe 2 [
(x: x + 2) # 2 + 2 = 4
(x: x * 2) # 4 * 2 = 8
]
=> 8
# ideal to do text transformations
pipe [ "a/b" "a/c" ] [
# create the cp command
(map (file: ''cp "${src}/${file}" $out\n''))
# concatenate all commands into one string
lib.concatStrings
# make that string into a nix derivation
(pkgs.runCommand "copy-to-out" {})
]
=> <drv which copies all files to $out>
The output type of each function has to be the input type
of the next function, and the last function returns the
final value.