Class: EM::Sequence

Inherits:
Object
  • Object
show all
Defined in:
lib/em-sequence.rb,
lib/em-sequence/block.rb,
lib/em-sequence/method.rb

Overview

EventMachine sequence runner.

Defined Under Namespace

Classes: Block, Method

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(target) ⇒ Sequence

Constructor.

Parameters:

  • target (Object) —

    target instance for the sequence



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# File 'lib/em-sequence.rb', line 61

def initialize(target)
    @target = target
    @stack = [ ]
    @vars = { }
end

Dynamic Method Handling

This class handles dynamic methods through the method_missing method

#method_missing(name, *args, &block) ⇒ Object

Handles method definitions in sequence declaration.

Parameters:

  • name (Symbol) —

    method name

  • args (Array) —

    input variables specification

  • block (Proc) —

    block which should return array of returned variables names



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# File 'lib/em-sequence.rb', line 76

def method_missing(name, *args, &block)
    @stack << Method::new(@target, name, args, block)
end

Instance Attribute Details

#last ⇒ Object

Returns last run sequence item result.

Returns:

  • Object



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# File 'lib/em-sequence.rb', line 53

def last
  @last
end

#stack ⇒ Array

Holds required calls stack. (So in fact sequence itself.)

Returns:

  • (Array) 


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# File 'lib/em-sequence.rb', line 35

def stack
  @stack
end

#target ⇒ Object

Holds target instance of the sequencer.

Returns:

  • (Object) 


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# File 'lib/em-sequence.rb', line 27

def target
  @target
end

#vars ⇒ Hash

Holds array of variables available and defined during sequence run.

Returns:

  • (Hash) 


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# File 'lib/em-sequence.rb', line 45

def vars
  @vars
end

Class Method Details

.run(target, &block) ⇒ Object

Declares and runs specified block in one call. Useful if you don’t expect any results.

Parameters:

  • target (Object) —

    target instance for the sequence

  • block (Proc) —

    sequence declaration

See Also:

Since:

  • 0.1.1



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# File 'lib/em-sequence.rb', line 178

def self.run(target, &block)
    self::new(target).declare(&block).run!
end

Instance Method Details

#block(*args, &block) ⇒ Object Also known as: b, blk

Declares block.

Given block must return Hash with variable names and values. If block is last item of the sequence, return value will be used as return value of the sequence.

Parameters:

  • args (Array) —

    array of arguments

  • block (Proc) —

    body of block



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# File 'lib/em-sequence.rb', line 137

def block(*args, &block)
    @stack << Block::new(block, args)
end

#declare(&block) ⇒ Sequence Also known as: decl

Receives the sequence declaration.

Examples:

bar.declare do

    # variable declaration
    variable :var, 3

    # method call declaration
    some_method(:var) { [:x, :y] }

    # inline block declaration and definition
    block(:x, :y) do |x, y|
        {:x => x + 1, :y => y + 1}
    end

    # some other methods
    other_method(:x, :y) { :x }
    another_method(:x)

end

Parameters:

  • block (Proc) —

    sequence declaration

Returns:



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# File 'lib/em-sequence.rb', line 107

def declare(&block)
    self.instance_eval(&block)
    return self
end

#run!(&callback) ⇒ Object

Runs the sequence.

Parameters:

  • callback (Proc) —

    callback for giving back result of lat item of the sequence



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# File 'lib/em-sequence.rb', line 151

def run!(&callback)
    worker = Proc::new do
        if not @stack.empty?
            @stack.shift.call(@vars) do |result, returning|
                @vars.merge! result
                @last = returning
                
                EM::next_tick { worker.call() }
            end
        elsif not callback.nil?
            EM::next_tick { callback.call(@last) }
        end
    end
    
    worker.call()
end

#variable(name, value) ⇒ Object Also known as: var

Declares variable.

Parameters:

  • name (Symbol) —

    name of the variable

  • value (Object) —

    value of the variable



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# File 'lib/em-sequence.rb', line 121

def variable(name, value)
    @vars[name] = value
end