C++ (Cpp) Term::isvar示例

// checks that the atom has the form f(x) = t[x],
// where f is a function symbol and t[x] is a term of x not containing f
// 09/05/2002, Manchester
bool Atom::isDefinition (Term& lhs, Term& rhs) const
{
  TRACER ( "Atom::isDefinition" );

  if ( ! isEquality() ) {
    return false;
  }

  // the atom is an equality
  Term l (args().head());
  Term r (args().second());
  if ( l.isvar() || r.isvar() ) {
    return false;
  }
  // l=r, both l and r are non-variables
  if ( r.defines(l) ) {
    lhs = l;
    rhs = r;
    return true;
  }

  if ( l.defines(r) ) {
    rhs = l;
    lhs = r;
    return true;
  }

  return false;
} // Term* Atom::isDefinition

示例#2

显示文件

文件： Atom.cpp 项目： kdgerring/sigma

// return true if the atoms are x = y, P[x] and P[y]
// 29/04/2002 Manchester
bool Atom::predicateMonotonicity (Atom a1, Atom a2, Atom a3)
{
  TRACER("Atom::predicateMonotonicity");

  if ( ! a1.isEquality() )
    return false;
  if ( a2.isEquality() )
    return false;
  if ( a3.isEquality() )
    return false;

  Term x (a1.args().head());
  Term y (a1.args().second());
  if ( ! x.isvar() || ! y.isvar() )
    return false;

  Var vx = x.var();
  Var vy = y.var();
  // variables must be different
  if ( vx == vy ) 
    return false;

  if ( a2.functor() != a3.functor() )
    return false;
  
  return a2.args().equalUpTo (a3.args(),vx,vy);
} // Atom::predicateMonotonicity