chinnurtb / erl-pipes

Hartmann pipes in Erlang

An implementation of Hartmann pipelines in Erlang. In short, they are extensions of the usual Unix pipes that allow building graphs of programs and thus one can implement a full data-flow environment.

Read more in the wiki.

Examples

Code example with current API, counting the number of lines in a file containing “=” and the number of lines that don’t contain it:

    P1 = pipes:pipe(cat, [FileName]),
    P2 = pipes:pipe(lines),
    P4 = pipes:pipe(grep, ["="]),
    P3 = pipes:pipe(count),
    P5 = pipes:pipe(count),
    
    pipes:connect([P1, P2, P4, P3]),
    pipes:connect({P4, nomatch}, P5),
    
    {WithEquals, WithoutEquals} = {pipes:get_result(P3), pipes:get_result(P5)}.

This will look in the future similar to the Unix-ish

    {WithEquals, WithoutEquals} = pipes:build(
      " cat $FileName | 
        lines | 
        g: grep \"=\" |
        count > $1
      ",
      " :g/nomatch |
        count > $2
      "
    ).