Class: Object

Inherits:
BasicObject
Defined in:
lib/funtools/recursion.rb,
lib/funtools/pattern-matching.rb

Instance Method Summary collapse

Instance Method Details

#defpattern(sym) ⇒ Object

Public: Define a method in the current scope which allow pattern matching function declaration to be used.

sym - Symbol defining the name of the method to be created. block - Block containing the logic for the function to be created.

Returns nothing.



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# File 'lib/funtools/pattern-matching.rb', line 11

def defpattern(sym)
  patterns = []
  self.class.send(:define_method, sym) do |*l, &b|
    patterns << ->(*n) do
      ->(*m) do
        flat_m = m.flatten
        flat_n = n.flatten
        if flat_m.length == flat_n.length
          e = flat_m.zip(n.flatten)
          unless e.reject { |e| e[0].nil? || e[0]==e[1] }.any?
            b.call(*flat_n)
          end
        end
      end.(l.flatten)
    end
  end

  yield

  self.send(:define_method, sym) do |*args|
    patterns.each do |pattern|
      result = pattern[args]
      break result unless result.nil?
    end
  end
end

#deftail(sym, &block) ⇒ Object

Public: Define a method in the current scope which will execute a given block recursively until a fixpoint is reached.

sym - Symbol defining the name of the method to be created. block - Block containing the logic for the function to be created.

Returns nothing.



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# File 'lib/funtools/recursion.rb', line 11

def deftail(sym, &block)
  self.send(:define_method, sym) do |*n|
    last = nil
    [1].cycle.reduce(n) { |c, e| break c if last == c; last = c; block[c] }
  end
end