# ZSH higher order functions

You can look at [yogsototh's blogpost] for the idea of higher order functions
in zsh.

## Install

If you are lazy just paste the following lines in your terminal:

    cd /tmp && \
    curl -O https://raw.github.com/yogsototh/zsh_functional/master/install.sh && \
    chmod u+x install.sh && . ./install.sh && \rm -f ./install.sh

If you want to have more control, 
clone this repo to `~/.zsh/functional` and add

    . ~/.zsh/functional/load

to your `.zshrc`

## Examples

Here are some examples with named functions (`map`, `filter`, `fold`):

    $ insideXY(){print -- "X $1 Y"}
    $ map insideXY a b c d
    X a Y
    X b Y
    X c Y
    X d Y
    
    $ add(){print -- $(($1+$2))}
    $ fold add {1..5}
    15

Here are some examples of using anonymous functions (`*l` and `*a`):

    $ filterl 'echo $1|grep a >/dev/null' ab cd ef ada
    ab
    ada

    $ folda '$1+$2' {1..5}
    15

    $ folda '$1*$2' {1..20}
    2432902008176640000

    $ mapl 'echo X $1:t Y' ~/.zsh/functional/src/*
    X each Y
    X filter Y
    X fold Y
    X map Y

    $ mapa '$1*2' {1..3}
    2
    4
    6

    $ mapl 'echo result $1' $(mapa '$1+5' $(mapa '$1*2' {1..3}))
    result 7
    result 9
    result 11

## Usage and documentation

Please refer to the tests so far until I've written simple proper docs for each
function. The function `map` and family will print out documentation for you
when calling them with no arguments.

Each of the method families, `map`, `each`, `filter` and `fold` are having a
"normal version" accompanied with lambda function version and a arithmetic
lambda version.

### Lambda functions

Use the versions ending with `l`, like `mapl`, `eachl`, `foldl`.

### Arithmetic lambda functions

Similarly, use the functions ending with `a`.

## Contributing

Good idea! Just add a test and implement the new functionality and send away
your pull request! :)

## Creds

Yann Esposito for the *HoF* idea and big thanks to [Sterling's blogpost] for
discovering and starting implementing the anonymous function features.

[yogsototh's blogpost]: http://yannesposito.com/Scratch/en/blog/Higher-order-function-in-zsh/
[Sterling's blogpost]:  http://nicholassterling.wordpress.com/2012/03/30/a-zsh-map-function/