Module: Predicate::Expr

Includes:
Factory
Included in:
BinaryFunc, Contradiction, DyadicComp, Exists, Identifier, In, Literal, NadicBool, Native, Not, Opaque, QualifiedIdentifier, SetOp, Tautology, UnaryFunc, Var
Defined in:
lib/predicate/sequel.rb,
lib/predicate/nodes/expr.rb,
lib/predicate/postgres/rewriter.rb

Constant Summary collapse

OP_NEGATIONS = 
{
  :eq  => :neq,
  :neq => :eq,
  :lt  => :gte,
  :lte => :gt,
  :gt  => :lte,
  :gte => :lt
}

Instance Method Summary collapse

Methods included from Factory

#_factor_predicate, #and, #comp, #contradiction, #empty, #from_hash, #h, #has_size, #identifier, #in, #literal, #match, #native, #not, #opaque, #or, #pg_array_empty, #pg_array_literal, #pg_array_overlaps, #placeholder, #qualified_identifier, #tautology, #var, #vars

Instance Method Details

#! ⇒ Object 



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# File 'lib/predicate/nodes/expr.rb', line 34

def !
  sexpr([:not, self])
end

#&(other) ⇒ Object 



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# File 'lib/predicate/nodes/expr.rb', line 40

def &(other)
  return other if other.contradiction?
  return self  if other.tautology?
  return other & self if other.dyadic_priority > self.dyadic_priority
  sexpr([:and, self, other])
end

#and_split(attr_list) ⇒ Object 



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# File 'lib/predicate/nodes/expr.rb', line 53

def and_split(attr_list)
  # If we have no reference to attr_list, then we are P2, else we are P1
  (free_variables & attr_list).empty? ? [ tautology, self ] : [ self, tautology ]
end

#attr_split ⇒ Object 



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# File 'lib/predicate/nodes/expr.rb', line 58

def attr_split
  # if I have only one variable reference, then I can return
  # myself mapped to that variable...
  if (vars = free_variables).size == 1
    { vars.first => self }
  else
    # I must still map myself to nil to meet the conjunction
    # specification
    { nil => self }
  end
end

#bind(binding) ⇒ Object 



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# File 'lib/predicate/nodes/expr.rb', line 82

def bind(binding)
  Binder.new(binding).call(self)
end

#constant_variables ⇒ Object 



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# File 'lib/predicate/nodes/expr.rb', line 86

def constant_variables
  []
end

#constants ⇒ Object 



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# File 'lib/predicate/nodes/expr.rb', line 90

def constants
  {}
end

#contradiction? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/predicate/nodes/expr.rb', line 18

def contradiction?
  false
end

#dyadic_priority ⇒ Object 



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# File 'lib/predicate/nodes/expr.rb', line 38

def dyadic_priority; 0; end

#identifier? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/predicate/nodes/expr.rb', line 30

def identifier?
  sexpr_type == :identifier
end

#literal? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/predicate/nodes/expr.rb', line 22

def literal?
  sexpr_type == :literal
end

#opaque? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/predicate/nodes/expr.rb', line 26

def opaque?
  sexpr_type == :opaque
end

#qualify(qualifier) ⇒ Object 



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# File 'lib/predicate/nodes/expr.rb', line 74

def qualify(qualifier)
  Qualifier.new(qualifier).call(self)
end

#rename(renaming) ⇒ Object 



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# File 'lib/predicate/nodes/expr.rb', line 70

def rename(renaming)
  Renamer.call(self, :renaming => renaming)
end

#sexpr(arg) ⇒ Object 



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# File 'lib/predicate/nodes/expr.rb', line 102

def sexpr(arg)
  Factory.sexpr(arg)
end

#tautology? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/predicate/nodes/expr.rb', line 14

def tautology?
  false
end

#to_hash ⇒ Object

Raises:

  • (ArgumentError) 


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# File 'lib/predicate/nodes/expr.rb', line 98

def to_hash
  raise ArgumentError, "Unable to represent #{self} to a Hash"
end

#to_postgres(*args) ⇒ Object 



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# File 'lib/predicate/postgres/rewriter.rb', line 41

def to_postgres(*args)
  Postgres::Rewriter.new(*args).call(self)
end

#to_s(scope = nil) ⇒ Object 



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# File 'lib/predicate/nodes/expr.rb', line 94

def to_s(scope = nil)
  ToS.call(self, scope: scope)
end

#to_sequel ⇒ Object 



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# File 'lib/predicate/sequel.rb', line 5

def to_sequel
  ToSequel.call(self)
end

#unqualify ⇒ Object 



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# File 'lib/predicate/nodes/expr.rb', line 78

def unqualify
  Unqualifier.new.call(self)
end

#|(other) ⇒ Object 



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# File 'lib/predicate/nodes/expr.rb', line 47

def |(other)
  return other if other.tautology?
  return self  if other.contradiction?
  sexpr([:or, self, other])
end