Class: Type

Inherits:
Object show all
Defined in:
lib/platypus/type.rb

Overview

Base class for Euphoria-like Types.

class KiloType < Type
  condition do |x|
    x.case? Integer
    x.kind_of?(Integer)
    x.respond_to?(:succ)
    x > 1000
  end
end

Becuase the x.something? is so common, TypeCast provides special “magic-dot” method to make defining these conditions more concise.

class KiloType < Type
  x.case? Integer
  x.kind_of?(Integer)
  x.respond_to?(:succ)
  x > 1000
end

While TypeCasts are not actual types in the sense they are not actual classes. They can be used for conversion by defining a “from_<class>” class method. In doing so you should make sure the result of the conversion conforms to the typecast. You can use the TypeCast.validate method to make that a bit easier. For instance:

class KiloType
  def from_string(str)
    validate(str.to_i)
  end
end

TypeCast also provides a helper DSL method that handles this for you.

class KiloType
  conversion String do |str|
    str.to_i
  end
end

This will define a method equivalent to the prior example.

Defined Under Namespace

Classes: Conditions

Class Method Summary collapse

Class Method Details

.===(obj) ⇒ Object 



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# File 'lib/platypus/type.rb', line 125

def self.===(obj)
  #conditions.all? do |s, a, b|
  #  obj.__send__(s, *a, &b)
  #end
  instance = new
  conditions.all? do |method|
    instance.__send__(method, obj)
  end
end

.check(on_or_off = nil) ⇒ Object

Activeate/Deactivate type-checking globally (NOT USED YET).



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# File 'lib/platypus/type.rb', line 52

def self.check(on_or_off=nil)
  @check = on_or_off unless on_or_off.nil?
  @check
end

.condition(&block) ⇒ Object 



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# File 'lib/platypus/type.rb', line 63

def self.condition(&block)
  @index ||= index
  @index = @index.succ
  define_method("condition_#{@index}", &block)
  #@conditions << block
end

.conditions ⇒ Object 



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# File 'lib/platypus/type.rb', line 119

def self.conditions
  #x.__conditions__ + (@conditions || []) + (defined?(super) ? super : [])
  instance_methods.select{ |m| m.to_s =~ /^condition_/ }
end

.conversion(klass, &block) ⇒ Object 



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# File 'lib/platypus/type.rb', line 71

def self.conversion(klass, &block)
  name = klass.name.downcase.gsub('::', '_')
  (class << self; self; end).class_eval do
    define_method("from_#{name}") do |from|
      r = block.call(from)
      validate(r)
    end
  end
end

.index ⇒ Object 



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# File 'lib/platypus/type.rb', line 113

def self.index
  methods = instance_methods.select{ |m| m.to_s =~ /^condition_/ }
  indexes = methods.map{ |m| m.split('_')[1].to_i }
  indexes.max || 0
end

.validate(obj) ⇒ Object

Raises:

  • (TypeError) 


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# File 'lib/platypus/type.rb', line 57

def self.validate(obj)
  raise TypeError unless self === obj
  return obj
end

.x ⇒ Object 



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# File 'lib/platypus/type.rb', line 82

def self.x
  @x ||= Conditions.new(self)
end