##Pipeline parse transform: a parse transform example (toy) pipe(InitialParameter, fun1(), fun2(7,), fun3(,4), funN())

will be transformed into

 funN(fun3(fun2(7, fun1(InitialParameter)), 4))

Given

pipe(InitP, Fn1, Fn2, ..., FnN)

The result of Fn1(InitP) will be given to Fn2 as its first free parameter. The result of that wil be passed to Fn3 in its first free parameter and so on. A function's free parameter is either the only parameter (function of arity 1) or the parameter indicated by the first instance of the underscore ('_') in its parameter list. This is really functional compositon.

Examples will make this more clear. It's an easy concept whose explanation I have butchered.

Currently, one can use pipe in: block, call, catch, case, if, fun, list comprehension, match, operator, try, try of, and unary operator form expressions.

Some examples include:

pipe(InitParameter,
     fun1(),
     fun2(7,_),
     fun3(_,4))

A = pipe(InitParameter,
     fun1(),
     fun2(7,_),
     fun3(_,4))
     
pipe(InitParameter,
     fun1(),
     fun2(7,_),
     fun3(_,4)) == Value

A = fun(X) ->    
        pipe(InitParameter,
            fun1(),
            fun2(7,_),
            fun3(_,4));
    (Y) ->   
            etc
    end
    
[pipe(InitParameter,
      fun1(),
      fun2(7,_),
      fun3(_,X)) || X <- lists:seq(1,10)]

Catch = (catch pipe("test",
                    list_to_binary(),
                    byte_size(),
                    add(_,0)))

##Alternative Syntax An alternative syntax has been hacked-in such that if the compile option {pipe, true} is supplied, the source file will be re-scanned converting

 |> "test" |> list_to_binary |> etc() :| 

into

 pipe("test", list_to_binary(), etc())

Notice that the file will be re-scanned in the parse-transform and, therefore, other transforms and incldued Macros might not play nicely.

##Usage Make sure the parse_transform file, pipeline.erl, is compiled as part of your project or in some other way ensure that the pipeline.beam is in your path.

Either include a compile directive in your .erl file

  -compile({parse_transform, pipeline}).

or use the compile directive

c(test, [{parse_transform, pipeline}]).

###Tests Compile pipeline_tests and run pipeline_tests:start().