Class: Factbase::Either

Inherits:

TermBase

• Object
• TermBase
• Factbase::Either

Defined in:

lib/factbase/terms/either.rb

Overview

Represents a logical “either” term. The term evaluates its operands and returns the first non-nil value.

Instance Method Summary

• #evaluate(fact, maps, fb) ⇒ Object, Boolean

  Evaluate term on a fact.

• #initialize(operands) ⇒ Either constructor

  Constructor.

Methods included from TermShared

#to_s

Constructor Details

#initialize(operands) ⇒ Either

Constructor.

Parameters:

• operands (Array) —

  Operands

# File 'lib/factbase/terms/either.rb', line 13

def initialize(operands)
  super()
  @operands = operands
  @op = :either
end

Instance Method Details

#evaluate(fact, maps, fb) ⇒ Object, Boolean

Evaluate term on a fact.

Parameters:

• fact (Factbase::Fact) —

  The fact

• maps (Array<Factbase::Fact>) —

  All maps available

• fb (Factbase) —

  Factbase to use for sub-queries

Returns:

• (Object) —

  First operand if not nil, otherwise second operand

• (Boolean) —

  True if first operand is false OR both are true

# File 'lib/factbase/terms/either.rb', line 25

def evaluate(fact, maps, fb)
  assert_args(2)
  v = _values(0, fact, maps, fb)
  return v unless v.nil?
  _values(1, fact, maps, fb)
end