Class: Factbase::Rules

Inherits:
Object
  • Object
show all
Defined in:
lib/factbase/rules.rb

Overview

A decorator of a Factbase, that checks rules on every set.

Say, you want every fact to have foo property. You want any attempt to insert a fact without this property to lead to a runtime error. Here is how:

fb = Factbase.new
fb = Factbase::Rules.new(fb, '(exists foo)')
fb.txn do |fbt|
  f = fbt.insert
  f.bar = 3 # No exception here
end # Runtime exception here (transaction won't commit)
Author

Yegor Bugayenko ([email protected])

Copyright

Copyright © 2024-2025 Yegor Bugayenko

License

MIT

Defined Under Namespace

Classes: Check, Fact, Later, Query

Instance Method Summary collapse

Constructor Details

#initialize(fb, rules, check = Check.new(rules), uid: nil) ⇒ Rules

Returns a new instance of Rules.



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# File 'lib/factbase/rules.rb', line 30

def initialize(fb, rules, check = Check.new(rules), uid: nil)
  raise 'The "fb" is nil' if fb.nil?
  @fb = fb
  raise 'The "rules" is nil' if rules.nil?
  @rules = rules
  raise 'The "check" is nil' if check.nil?
  @check = check
  @uid = uid
end

Instance Method Details

#insert ⇒ Object 



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# File 'lib/factbase/rules.rb', line 40

def insert
  Fact.new(@fb.insert, @check, @fb)
end

#query(term, maps = nil) ⇒ Object 



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# File 'lib/factbase/rules.rb', line 44

def query(term, maps = nil)
  Query.new(@fb.query(term, maps), @check, self)
end

#txn ⇒ Object 



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# File 'lib/factbase/rules.rb', line 48

def txn
  before = @check
  later = Later.new(@uid)
  @check = later
  @fb.txn do |fbt|
    churn = Factbase::Churn.new
    yield Factbase::Tallied.new(Factbase::Rules.new(fbt, @rules, @check, uid: @uid), churn)
    @check = before
    unless churn.zero?
      fbt.query('(always)').each do |f|
        next unless later.include?(f)
        @check.it(f, @fb)
      end
    end
  end
end