Class: PatternMatch::ValuePattern

Inherits:
PatternElement show all
Defined in:
lib/egison/core.rb

Defined Under Namespace

Classes: BindingModule

Instance Attribute Summary

Attributes inherited from Pattern

#quantified

Instance Method Summary collapse

Methods inherited from Pattern

#match_stream, #to_a

Constructor Details

#initialize(ctx, expr) ⇒ ValuePattern

Returns a new instance of ValuePattern.



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# File 'lib/egison/core.rb', line 246

def initialize(ctx, expr)
  super()
  @ctx = ctx
  @expr = expr
end

Instance Method Details

#binding_module(obj) ⇒ Object 



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# File 'lib/egison/core.rb', line 287

def binding_module(obj)
  m = obj.singleton_class.ancestors.find { |i| i.kind_of?(BindingModule) }
  unless m
    m = BindingModule.new
    obj.singleton_class.class_eval do
      if respond_to?(:prepend, true)
        prepend m
      else
        include m
      end
    end
  end
  m
end

#match(tgt, bindings) ⇒ Object 



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# File 'lib/egison/core.rb', line 252

def match(tgt, bindings)
  val = with_bindings(@ctx, bindings, {:expr => @expr}) { eval expr }
  if val.__send__(:===, tgt)
    [[[], []]]
  else
    []
  end
end

#with_bindings(obj, bindings, ext_bindings, &block) ⇒ Object 



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# File 'lib/egison/core.rb', line 264

def with_bindings(obj, bindings, ext_bindings, &block)
  binding_module(obj).module_eval do
    begin
      bindings.each do |name, val|
        define_method(name) { val }
        private name
      end
      ext_bindings.each do |name, val|
        define_method(name) { val }
        private name
      end
      obj.instance_eval(&block)
    ensure
      bindings.each do |name, _|
        remove_method(name)
      end
      ext_bindings.each do |name, _|
        remove_method(name)
      end
    end
  end
end