Class: Factbase::Prev

Inherits:

TermBase

• Object
• TermBase
• Factbase::Prev

Defined in:

lib/factbase/terms/prev.rb

Overview

of terms based on provided operands and facts.

Instance Method Summary

• #evaluate(fact, maps, fb) ⇒ Object

  Evaluate term on a fact.

• #initialize(operands) ⇒ Prev constructor

  Constructor.

Methods included from TermShared

#to_s

Constructor Details

#initialize(operands) ⇒ Prev

Constructor.

Parameters:

• operands (Array) —

  Operands

# File 'lib/factbase/terms/prev.rb', line 12

def initialize(operands)
  super()
  @operands = operands
end

Instance Method Details

#evaluate(fact, maps, fb) ⇒ Object

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) —

  The previous value

# File 'lib/factbase/terms/prev.rb', line 22

def evaluate(fact, maps, fb)
  assert_args(1)
  before = @prev
  v = _values(0, fact, maps, fb)
  @prev = v
  before
end