Class: Maybe
- Inherits:
-
Object
show all
- Defined in:
- lib/maybe.rb
Instance Method Summary
collapse
Constructor Details
#initialize(value) ⇒ Maybe
Returns a new instance of Maybe.
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# File 'lib/maybe.rb', line 9
def initialize(value)
@value = value
self.join
end
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Dynamic Method Handling
This class handles dynamic methods through the method_missing method
#method_missing(method_name, *args) ⇒ Object
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# File 'lib/maybe.rb', line 14
def method_missing(method_name, *args)
self.fmap do |value|
value.send(method_name,*args) do |*block_args|
yield(*block_args) if block_given?
end
end
end
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Instance Method Details
#fmap ⇒ Object
Given that the value is of type A takes a function from A->B and returns M (a monad with a value of type B)
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# File 'lib/maybe.rb', line 40
def fmap
if(@value==nil)
self
else
Maybe.new(yield(@value))
end
end
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#join ⇒ Object
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# File 'lib/maybe.rb', line 52
def join
if(@value.is_a?(Maybe))
@value = value.value
end
self
end
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#nil? ⇒ Boolean
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# File 'lib/maybe.rb', line 48
def nil?
@value==nil
end
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#pass ⇒ Object
Given that the value is of type A takes a function from A->M and returns M (a monad with a value of type B)
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# File 'lib/maybe.rb', line 33
def pass
fmap {|*block_args| yield(*block_args)}.join
end
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#value(value_if_nil = nil) ⇒ Object
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# File 'lib/maybe.rb', line 22
def value(value_if_nil=nil)
if(value_if_nil!=nil && @value==nil)
value_if_nil
else
@value
end
end
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#value=(value) ⇒ Object
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# File 'lib/maybe.rb', line 60
def value=(value)
@value = value
end
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