#include "AST.h"
#include "llist.h"


static PointNode *slice( const TreeListNode &args, int index, SourcePosn where )
{
  llist< TreeNode * > *exprs = 0;
  
  for (int sweep = args.arity(); sweep--; )
    {
      const TreeNode &arg = *args.child( sweep );
      assert( arg.arity() >= 2 );
      assert( arg.arity() <= 3 );
      push( exprs, args.child( sweep )->child( index ) );
    }
  
  return new PointNode( exprs, where );
}


TreeNode *DomainNode::rewrite( const FieldContext *context )
{
  TreeNode::rewrite( context );

  TreeNode *lower;
  TreeNode *upper;
  TreeNode *stride = 0;

  if (args()->child(0)->child(0)->type()->isPointType())
    {
      // preassembled points
      
      assert( args()->arity() == 1 );
      assert( args()->child(0)->arity() >= 2 );
      assert( args()->child(0)->arity() <= 3 );

      const TreeNode &arg = *args()->child(0);
      
      lower = arg.child(0);
      upper = arg.child(1);

      if (arg.arity() == 3)
	stride = arg.child(2);
    }
  else
    {
      // assemble points ourselves

      lower = slice( *args(), 0, where );
      upper = slice( *args(), 1, where );

      if (args()->child(0)->arity() == 3)
	stride = slice( *args(), 2, where );
    }

  // create a default unit stride if none was given
  if (!stride)
    {
      Literal one( (int32) 1 );
      llist< TreeNode * > *ones = 0;
      
      for (unsigned dimension = type()->tiArity(); dimension--; )
	push( ones, (TreeNode *) new PrimitiveLitNode( one, where ) );

      stride = new PointNode( ones, where );
    }

  llist< TreeNode * > * domainArgs = 0;
  push( domainArgs, stride );
  push( domainArgs, upper );
  push( domainArgs, lower );
  
  TreeNode *args = new TreeListNode( domainArgs, where );
  DomainNode *replacement = new DomainNode( cons( args ), where );
  return replacement;
}