#include "../AST.h"


static string arguments( int count )
{
  string result( int2string( count ) );
  result += " argument";
  if (count == 1) result += 's';
  return result;
}


ClassDecl *TemplateInstanceTypeNode::checkTemplateUse() const
{
  TypeDecl &typeDecl = *dtype()->decl();
  
  if (!typeDecl.category() & (Decl::Class | Decl::Interface))
    {
      error() << typeDecl.errorName() << " is neither a class nor an interface" << endl;
      return UnknownClassDecl;
    }

  ClassDecl &basisDecl = static_cast< ClassDecl & >( typeDecl );

  if (!basisDecl.instantiations)
    {
      const string errorName( basisDecl.errorName() );
      error() << errorName << " is not a template" << endl;
      basisDecl.source()->message() << errorName << " originally declared here" << endl;
      return UnknownClassDecl;
    }

  TreeListNode &formals = *basisDecl.source()->parent()->params();
  TreeListNode &actuals = *args();
  const int numFormals = formals.arity();
  const int numActuals = actuals.arity();
  
  if (numFormals != numActuals)
    {
      actuals.error() <<   arguments( numActuals ) << " used to instantiate template " << errorName() << endl;
      formals.message() << arguments( numFormals ) << " expected by template declaration" << endl;
      return UnknownClassDecl;
    }

  // sanity checked ok; now we can disambiguate

  for (int arg = 0; arg < numActuals; ++arg)
    {
      TreeNode &formal = *formals.child( arg );
      TreeNode &actual = *actuals.child( arg );
      TreeNode *fixed = formal.fixTemplateActual( actual );
      actuals.child( arg, fixed );
    }
  
  return 0;
}



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