Class: Factbase::Defn

Inherits:
TermBase show all
Defined in:
lib/factbase/terms/defn.rb

Overview

Factbase::Defn is responsible for defining new terms in the Factbase system.

Author

Yegor Bugayenko (yegor256@gmail.com)

Copyright

Copyright © 2024-2026 Yegor Bugayenko

License

MIT

Instance Method Summary collapse

Methods inherited from TermBase

#to_s

Constructor Details

#initialize(operands) ⇒ Defn

Constructor.

Parameters:

  • operands (Array) —

    Operands



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# File 'lib/factbase/terms/defn.rb', line 15

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

Instance Method Details

#evaluate(_fact, _maps, _fb) ⇒ Object

Evaluate term on a fact.

Parameters:

Returns:

  • (Object) —

    Term definition result

Raises:

  • (ArgumentError) 


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

def evaluate(_fact, _maps, _fb)
  assert_args(2)
  fn = @operands[0]
  raise(ArgumentError, "A symbol expected as first argument of 'defn'") unless fn.is_a?(Symbol)
  raise(ArgumentError, "Can't use '#{fn}' name as a term") if Factbase::Term.method_defined?(fn)
  raise(ArgumentError, "Term '#{fn}' is already defined") if Factbase::Term.private_method_defined?(fn, false)
  raise(ArgumentError, "The '#{fn}' is a bad name for a term") unless fn.match?(/^[a-z_]+$/)
  # rubocop:disable Security/Eval
  eval(
    "class Factbase::Term\nprivate\ndef #{fn}(fact, maps, fb)\n#{@operands[1]}\nend\nend",
    binding, __FILE__, __LINE__ - 1
  )
  # rubocop:enable Security/Eval
  true
end