//Parser states are distinguished by the subset of kernel LR0 items.
// So when we derive new LR0-item list by shift operation,
// we need to find out if we have already a state with the same LR0Item list.
// We do it by looking up in a state hash by a key - [LR0 item list key].
// Each list's key is a concatenation of items' IDs separated by ','.
// Before producing the key for a list, the list must be sorted;
// thus we garantee one-to-one correspondence between LR0Item sets and keys.
// And of course, we count only kernel items (with dot NOT in the first position).
#endregion
public static string ComputeLR0ItemSetKey(LR0ItemSet items)
{
if (items.Count == 0)
{
return("");
}
//Copy non-initial items to separate list, and then sort it
LR0ItemList itemList = new LR0ItemList();
foreach (var item in items)
{
itemList.Add(item);
}
//quick shortcut
if (itemList.Count == 1)
{
return(itemList[0].ID.ToString());
}
itemList.Sort(CompareLR0Items); //Sort by ID
//now build the key
StringBuilder sb = new StringBuilder(255);
foreach (LR0Item item in itemList)
{
sb.Append(item.ID);
sb.Append(",");
}//foreach
return(sb.ToString());
}
private string CalcItemListKey(LR0ItemList items)
{
items.Sort((x, y) => x.ID - y.ID); //Sort by ID
if (items.Count == 0)
{
return("");
}
if (items.Count == 1 && items[0].IsKernel)
{
return(items[0].ID.ToString());
}
StringBuilder sb = new StringBuilder(1024);
foreach (LR0Item item in items)
{
if (item.IsKernel)
{
sb.Append(item.ID);
sb.Append(",");
}
}
return(sb.ToString());
}
//Parser states are distinguished by the subset of kernel LR0 items.
// So when we derive new LR0-item list by shift operation,
// we need to find out if we have already a state with the same LR0Item list.
// We do it by looking up in a state hash by a key - [LR0 item list key].
// Each list's key is a concatenation of items' IDs separated by ','.
// Before producing the key for a list, the list must be sorted;
// thus we garantee one-to-one correspondence between LR0Item sets and keys.
// And of course, we count only kernel items (with dot NOT in the first position).
public static string ComputeLR0ItemSetKey(LR0ItemSet items)
{
if (items.Count == 0) return string.Empty;
//Copy non-initial items to separate list, and then sort it
LR0ItemList itemList = new LR0ItemList();
itemList.AddRange(items);
//quick shortcut
if (itemList.Count == 1)
return itemList[0].ID.ToString();
itemList.Sort(CompareLR0Items); //Sort by ID
//now build the key
StringBuilder sb = new StringBuilder(100);
foreach (LR0Item item in itemList) {
sb.Append(item.ID);
sb.Append(",");
}//foreach
return sb.ToString();
}
//Parser states are distinguished by the subset of kernel LR0 items.
// So when we derive new LR0-item list by shift operation,
// we need to find out if we have already a state with the same LR0Item list.
// We do it by looking up in a state hash by a key - [LR0 item list key].
// Each list's key is a concatenation of items' IDs separated by ','.
// Before producing the key for a list, the list must be sorted;
// thus we garantee one-to-one correspondence between LR0Item sets and keys.
// And of course, we count only kernel items (with dot NOT in the first position).
#endregion
private string CalcItemListKey(LR0ItemList items)
{
items.Sort(ById); //Sort by ID
if (items.Count == 0)
{
return("");
}
//quick shortcut
if (items.Count == 1 && items[0].IsKernel)
{
return(items[0].ID.ToString());
}
StringBuilder sb = new StringBuilder(1024);
foreach (LR0Item item in items)
{
if (item.IsKernel)
{
sb.Append(item.ID);
sb.Append(",");
}
}//foreach
return(sb.ToString());
}
private string CalcItemListKey(LR0ItemList items)
{
items.Sort((x, y) => x.ID - y.ID); //Sort by ID
if (items.Count == 0) return "";
if (items.Count == 1 && items[0].IsKernel)
return items[0].ID.ToString();
StringBuilder sb = new StringBuilder(1024);
foreach (LR0Item item in items)
{
if (item.IsKernel)
{
sb.Append(item.ID);
sb.Append(",");
}
}
return sb.ToString();
}
