Class: Factbase::Env

Inherits:

TermBase

• Object
• TermBase
• Factbase::Env

Defined in:

lib/factbase/terms/env.rb

Overview

The ‘Factbase::Env` class is used to evaluate terms based on environment variables. It retrieves the value of an environment variable or returns a default value if the variable is not set.

Instance Method Summary

• #evaluate(fact, maps, fb) ⇒ String

  Evaluate term on a fact.

• #initialize(operands) ⇒ Env constructor

  Constructor.

Methods included from TermShared

#to_s

Constructor Details

#initialize(operands) ⇒ Env

Constructor.

Parameters:

• operands (Array) —

  Operands

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

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

Instance Method Details

#evaluate(fact, maps, fb) ⇒ String

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:

• (String) —

  The value of the environment variable or the default

# File 'lib/factbase/terms/env.rb', line 23

def evaluate(fact, maps, fb)
  assert_args(2)
  n = _values(0, fact, maps, fb)[0]
  ENV.fetch(n.upcase) { _values(1, fact, maps, fb)[0] }
end