Class: ActiveFacts::CQL::Compiler::Constraint

Inherits:
Definition
  • Object
show all
Defined in:
lib/activefacts/cql/compiler/constraint.rb

Instance Attribute Summary

Attributes inherited from Definition

#constellation, #tree, #vocabulary

Instance Method Summary collapse

Methods inherited from Definition

#all_bindings_in_clauses, #build_all_steps, #build_step, #build_variables, #source

Constructor Details

#initialize(context_note, enforcement, clauses_lists = []) ⇒ Constraint

Returns a new instance of Constraint.



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# File 'lib/activefacts/cql/compiler/constraint.rb', line 49

def initialize context_note, enforcement, clauses_lists = []
  if context_note.is_a?(Treetop::Runtime::SyntaxNode) && !context_note.empty?
    context_note = context_note.empty? ? nil : context_note.ast
  else
    context_note = nil  # Perhaps a context note got attached to one of the clauses. Steal it.
    clauses_lists.detect do |clauses_list|
      if c = clauses_list.last.context_note
        context_note = c
        clauses_list.last.context_note = nil
      end
    end
  end
  @context_note = context_note
  @enforcement = enforcement
  @clauses_lists = clauses_lists
end

Instance Method Details

#bind_clauses(extra = []) ⇒ Object 



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# File 'lib/activefacts/cql/compiler/constraint.rb', line 75

def bind_clauses extra = []
  @context = CompilationContext.new(@vocabulary)
  @context.left_contraction_allowed = true

  @context.bind @clauses_lists, extra
  @clauses_lists.map do |clauses_list|
    @context.left_contractable_clause = nil # Don't contract outside this set of clauses
    clauses_list.each do |clause| 
      fact_type = clause.match_existing_fact_type @context
      raise "Unrecognised fact type #{clause.inspect} in #{self.class}" unless fact_type
      raise "Negated fact type #{clause.inspect} in #{self.class} is not yet supported" if clause.certainty == false
    end
  end

  # Any constrained roles will be first identified here.
  # This means that they can't introduce role names.
  loose_binding

  # Ok, we have bound all players by subscript/role_name, by adjectives, and by loose binding,
  # and matched all the fact types that matter. Now assemble a query (with all steps) for
  # each query list, and build an array of the bindings that are involved in the steps.
  @bindings_by_list =
    @clauses_lists.map do |clauses_list|
      all_bindings_in_clauses(clauses_list)
    end

  warn_ignored_queries
end

#common_bindings ⇒ Object 



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# File 'lib/activefacts/cql/compiler/constraint.rb', line 180

def common_bindings
  @common_bindings ||= @bindings_by_list[1..-1].inject(@bindings_by_list[0]) { |r, b| r & b }
  raise "#{self.class} must cover some of the same roles, see #{@bindings_by_list.inspect}" unless @common_bindings.size > 0
  @common_bindings
end

#compile ⇒ Object 



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# File 'lib/activefacts/cql/compiler/constraint.rb', line 66

def compile
  @context_note.compile @constellation, @constraint if @context_note
  @constraint
end

#loose_bind ⇒ Object 



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# File 'lib/activefacts/cql/compiler/constraint.rb', line 147

def loose_bind
  # Apply loose binding over applicable @roles:
  trace :binding, "Check for loose bindings on #{@roles.size} roles in #{self.class.name}" do
    @roles.each do |ref|
      if ref.binding.refs.size < @clauses_lists.size+1
        trace :binding, "Insufficient bindings for #{ref.inspect} (#{ref.binding.refs.size}, expected #{@clauses_lists.size+1}), attempting loose binding" do
          @clauses_lists.each do |clauses_list|
            candidates = []
            next if clauses_list.
              detect do |clause|
                trace :binding, "Checking #{clause.inspect}"
                clause.refs.
                  detect do |vr|
                    already_bound = vr.binding == ref.binding
                    if !already_bound && vr.player == ref.player
                      candidates << vr
                    end
                    already_bound
                  end
              end
            trace :binding, "Attempting loose binding for #{ref.inspect} in #{clauses_list.inspect}, from the following candidates: #{candidates.inspect}"

            if candidates.size == 1
              trace :binding, "Rebinding #{candidates[0].inspect} to #{ref.inspect}"
              candidates[0].rebind_to(@context, ref)
            end
          end
        end
      end
    end
  end
end

#loose_bind_wherever_possible ⇒ Object 



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# File 'lib/activefacts/cql/compiler/constraint.rb', line 114

def loose_bind_wherever_possible
  # Apply loose binding over applicable roles:
  trace :binding, "Loose binding on #{self.class.name}" do
    @clauses_lists.each do |clauses_list|
      clauses_list.each do |clause|
        clause.refs.each_with_index do |ref, i|
          next if ref.binding.refs.size > 1
#                  if clause.side_effects && !clause.side_effects.role_side_effects[i].residual_adjectives
#                    trace :binding, "Discounting #{ref.inspect} as needing loose binding because it has no residual_adjectives"
#                    next
#                  end
          # This ref didn't match any other ref. Have a scout around for a suitable partner
          candidates = @context.bindings.
            select do |key, binding|
              binding.player == ref.binding.player and
                binding != ref.binding and
                binding.role_name == ref.binding.role_name and  # Both will be nil if they match
                # REVISIT: Don't bind to a binding with a role occurrence in the same clause
                !binding.refs.detect{|vr|
                  x = vr.clause == clause
                  # puts "Discounting binding #{binding.inspect} as a match for #{ref.inspect} because it's already bound to a player in #{ref.clause.inspect}" if x
                  x
                }
            end.map{|k,b| b}
          next if candidates.size != 1  # Fail
          trace :binding, "Loose binding #{ref.inspect} to #{candidates[0].inspect}"
          ref.rebind_to(@context, candidates[0].refs[0])
        end
      end
    end
  end
end

#loose_binding ⇒ Object 



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# File 'lib/activefacts/cql/compiler/constraint.rb', line 71

def loose_binding
  # Override for constraint types that need loose binding (same role player matching with different adjectives)
end

#to_s ⇒ Object 



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# File 'lib/activefacts/cql/compiler/constraint.rb', line 186

def to_s
  "#{self.class.name.sub(/.*::/,'')}" + (@clauses_lists.size > 0 ? " over #{@clauses_lists.inspect}" : '')
end

#warn_ignored_queries ⇒ Object 



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# File 'lib/activefacts/cql/compiler/constraint.rb', line 104

def warn_ignored_queries
  # Warn about ignored queries
  @clauses_lists.each do |clauses_list|
    fact_types = clauses_list.map{|clauses| (rr = clauses.refs[0].role_ref) && rr.role.fact_type}.compact.uniq
    if fact_types.size > 1
      raise "------->>>> join ignored in #{self.class}: #{fact_types.map{|ft| ft.preferred_reading.expand}*' and '}"
    end
  end
end