bsielski_control_flow

bsielski Control Flow

A couple of classes for organizing objects in simple data flow structures (conditional loops, pipelines etc.).

When to use it?

Who knows. Maybe in pseudo-funtional programming.

Installation

Add this line to your application's Gemfile:

gem 'bsielski_control_flow'

And then execute:

$ bundle

Or install it yourself as:

$ gem install bsielski_control_flow

Usage

Reqiure proper class.

require "c_flow/pipeline"

Use it.

square_number_generator = CFlow:Pipeline.new(procs: [random_int, square])

All classes have just one public method: #call. This method takes always one argument.

Some classes have dependencies (injected in constructor) called "procs". They are objects that respond to #call method. This method takes one argument or variable number of arguments (it depends of object's role).

API

Class CFlow::Pipeline

It passes a value through every proc and returns a final value. Output of the previous proc is input of the next proc.

Source code:

module CFlow
  class Pipeline
    def initialize(procs:)
      @procs = procs
    end
    
    def call(input)
      @procs.each do |proc|
        input = proc.call(input)
      end
      input
    end
  end
end

Require

require "c_flow/pipeline"

Constructor

CFlow:Pipeline.new(procs: procs) # => new_pipeline

Paramaters:

• procs - an array of procs or objects responding on .call message with one argument. The first proc takes the "main" input of the class. THe result is passed to the next proc as input. The output of the last proc is the output of .call method of Pipeline class.

Class CFlow::Self

It returns unmodified argument.

Source code:

module CFlow
  class Self
    def call(input)
      input
    end
  end
end

Require

require "c_flow/self"

Constructor

CFlow:Self.new # => new_self

Class CFlow::True

It returns true no matter what input it takes.

Source code:

module CFlow
  class True
    def call(input)
      true
    end
  end
end

Require

require "c_flow/true"

Constructor

CFlow:True.new # => new_true

Class CFlow::False

It returns false no matter what input it takes.

Source code:

module CFlow
  class False
    def call(input)
      false
    end
  end
end

Require

require "c_flow/false"

Constructor

CFlow:False.new # => new_false

Class CFlow::Combine

It passes input to each helper proc, then it passes the outputs to one proc and returns the output.

Source code:

module CFlow
  class Combine
    def initialize(combine_proc:, sub_procs:)
      @sub_procs = sub_procs
      @combine_proc = combine_proc
    end
    
    def call(input)
      sub_proc_outputs = []
      @sub_procs.each do |sub_proc|
        sub_proc_outputs << sub_proc.call(input)
      end
      @combine_proc.call(*sub_proc_outputs)
    end
  end
end

Require

require "c_flow/combine"

Constructor

CFlow::Combine.new(sub_procs: sub_procs, combine_proc: combine_proc) # => new_combine

Paramaters:

• sub_procs - an array of procs or objects responding on .call message with one argument. Each of them takes the "main" value a an argument and return an output. All aoutpus are pased to combine_proc.
• combine_procs - a proc or object responding on .call message with one or many arguments. The output of this proc is the output of the .call method of the Combine class.

Class CFlow::UntilTrueLoop

It passes input to condition_proc and if the result is not true it pases the input to loop_proc until the result is true.

Source code:

module CFlow
  class UntilTrueLoop
    def initialize(condition_proc:, loop_proc:)
      @loop_proc = loop_proc
      @condition_proc = condition_proc
    end
    
    def call(input)
      until @condition_proc.call(input) do
        input = @loop_proc.call(input)
      end
      input
    end
  end
end

Require

require "c_flow/until_true_loop"

Constructor

CFlow::UntilTrueLoop.new(condition_proc: condition_proc, loop_proc: loop_proc) # => new_loop

Paramaters:

• condition_proc - proc or object responding on .call message with one argument. At the beginning it takes the input from .call method from UntilTrueLoop class. If an output is truthy the output is returned as the output of .call message of UntilTrueLoop class.
• loop_proc - a proc or objects responding on .call message with one argument.

To do features

• Examples in the documentation and source code.
• More classes.

License

The gem is available as open source under the terms of the MIT License.