Class: Factbase::Query

Inherits:
Object
  • Object
show all
Includes:
Enumerable
Defined in:
lib/factbase/query.rb

Overview

Query.

This is an internal class, it is not supposed to be instantiated directly. It is created by the query() method of the Factbase class.

It is NOT thread-safe!

Author

Yegor Bugayenko ([email protected])

Copyright

Copyright © 2024-2026 Yegor Bugayenko

License

MIT

Instance Method Summary collapse

Constructor Details

#initialize(maps, term, fb) ⇒ Query

Constructor.



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# File 'lib/factbase/query.rb', line 28

def initialize(maps, term, fb)
  @maps = maps
  @term = term.is_a?(String) ? Factbase::Syntax.new(term).to_term : term
  @fb = fb
end

Instance Method Details

#delete!(fb = @fb, id: '_id') ⇒ Integer

Delete all facts that match the query.



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# File 'lib/factbase/query.rb', line 84

def delete!(fb = @fb, id: '_id')
  deleted = 0
  ids = []
  each(fb) do |f|
    i = f[id]
    unless i
      ids = nil
      break
    end
    ids << i.first
  end
  @maps.delete_if do |m|
    d =
      if ids
        i = m[id]&.first
        i && ids.include?(i)
      else
        @term.evaluate(Factbase::Fact.new(m), @maps, fb)
      end
    deleted += 1 if d
    d
  end
  deleted
end

#each(fb = @fb, params = {}) {|Fact| ... } ⇒ Integer

Iterate facts one by one.

Yields:

  • (Fact) —

    Facts one-by-one



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# File 'lib/factbase/query.rb', line 45

def each(fb = @fb, params = {})
  return to_enum(__method__, fb, params) unless block_given?
  yielded = 0
  params = params.transform_keys(&:to_s) if params.is_a?(Hash)
  maybe = @term.predict(@maps, fb, Factbase::Tee.new({}, params))
  maybe ||= @maps unless maybe.equal?(@maps)
  maybe.each do |m|
    extras = {}
    f = Factbase::Fact.new(m)
    f = Factbase::Tee.new(f, params)
    a = Factbase::Accum.new(f, extras, false)
    r = @term.evaluate(a, @maps, fb)
    unless r.is_a?(TrueClass) || r.is_a?(FalseClass)
      raise "Unexpected evaluation result of type #{r.class}, must be Boolean at #{@term.inspect}"
    end
    next unless r
    yield Factbase::Accum.new(f, extras, true)
    yielded += 1
  end
  yielded
end

#one(fb = @fb, params = {}) ⇒ String|Integer|Float|Time|Array|NilClass

Read a single value.



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# File 'lib/factbase/query.rb', line 71

def one(fb = @fb, params = {})
  params = params.transform_keys(&:to_s) if params.is_a?(Hash)
  r = @term.evaluate(Factbase::Tee.new(Factbase::Fact.new({}), params), @maps, fb)
  unless %w[String Integer Float Time Array NilClass].include?(r.class.to_s)
    raise "Incorrect type #{r.class} returned by #{@term.inspect}"
  end
  r
end

#to_s ⇒ String

Print it as a string.



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# File 'lib/factbase/query.rb', line 36

def to_s
  @term.to_s
end