/// <summary>
/// Creates nodes in the trie to capture all the don't care (unbound) locations in the pattern.
/// </summary>
private ShapeNode CreateDontCareNodes()
{
int i;
bool isExpanded;
ShapeNode n;
ShapeNode[] children;
return(Pattern.Compute <ShapeNode>(
(x, s) => x.Groundness == Groundness.Variable ? x.Args : null,
(x, ch, s) =>
{
if (x.Symbol.Arity == 0)
{
if (Executer.IsUnboundPatternVariable(x))
{
return new ShapeNode(true);
}
else
{
return null;
}
}
Contract.Assert(x.Symbol.IsDataConstructor);
isExpanded = false;
foreach (var m in ch)
{
if (m != null)
{
isExpanded = true;
break;
}
}
if (!isExpanded)
{
return null;
}
children = new ShapeNode[x.Symbol.Arity];
i = 0;
foreach (var m in ch)
{
children[i++] = m;
}
n = new ShapeNode();
n.AddRefinement((UserSymbol)x.Symbol, children);
return n;
}));
}