module Predicate::And

Public Instance Methods

&(other) click to toggle source
# File lib/predicate/nodes/and.rb, line 9
def &(other)
  case other
  when Tautology     then self
  when Contradiction then other
  when And           then sexpr(dup + other[1..-1])
  else               dup << other
  end
end
and_split(attr_list) click to toggle source
# File lib/predicate/nodes/and.rb, line 18
def and_split(attr_list)
  # Say we are X = X1 & X2 & X3
  # We will split each term: X = (X1 & Y1) & (X2 & Y2) & (X3 & Y3)
  # ... such that Y1, Y2, and Y2 makes no reference to attr_list
  # ... which is equivalent to (X1 & X2 & X3) & (Y1 & Y2 & Y3)
  # ... hence P1 & P2, that we return
  sexpr_body.inject([tautology, tautology]) do |(top,down),term|
    p1, p2 = term.and_split(attr_list)
    [top & p1, down & p2]
  end
end
attr_split() click to toggle source
# File lib/predicate/nodes/and.rb, line 30
def attr_split
  # Similar to and_split above, but the reasonning applies on
  # attribute names this time.
  sexpr_body.each_with_object({}) do |term, h|
    term.attr_split.each_pair do |a,p|
      h[a] = (h[a] || tautology) & p
    end
  end
end
constant_variables() click to toggle source
# File lib/predicate/nodes/and.rb, line 40
def constant_variables
  sexpr_body.inject([]) do |cvars,expr|
    cvars | expr.constant_variables
  end
end
constants() click to toggle source
# File lib/predicate/nodes/and.rb, line 46
def constants
  sexpr_body.each_with_object({}) do |op, cs|
    cs.merge!(op.constants){|k,v1,v2| v1 }
  end
end
evaluate(tuple) click to toggle source
# File lib/predicate/nodes/and.rb, line 52
def evaluate(tuple)
  sexpr_body.all?{|operand| operand.evaluate(tuple) }
end
operator_symbol() click to toggle source
# File lib/predicate/nodes/and.rb, line 5
def operator_symbol
  :'&&'
end
to_hash() click to toggle source
Calls superclass method
# File lib/predicate/nodes/and.rb, line 56
def to_hash
  sexpr_body.inject({}) do |p,term|
    p.merge(term.to_hash){|k,v1,v2|
      super unless v1 == v2
      v1
    }
  end
end