public readonly LR0ItemList LR0Items = new LR0ItemList(); //LR0 items based on this production
public Production(bool isInitial, NonTerminal lvalue, BnfTermList rvalues)
{
LValue = lvalue;
//copy RValues skipping Empty pseudo-terminal
foreach (BnfTerm rv in rvalues)
{
if (rv != Grammar.Empty)
{
RValues.Add(rv);
}
}
//Calculate flags
foreach (BnfTerm term in RValues)
{
Terminal terminal = term as Terminal;
if (terminal == null)
{
continue;
}
HasTerminals = true;
if (terminal.Category == TokenCategory.Error)
{
IsError = true;
}
}//foreach
//Note that we add an extra LR0Item with p = RValues.Count
for (int p = 0; p <= RValues.Count; p++)
{
LR0Items.Add(new LR0Item(this, p));
}
}//constructor
public BnfExpression MakePlusRule(NonTerminal listNonTerminal, BnfTerm delimiter, BnfTerm listMember)
{
listNonTerminal.SetOption(TermOptions.IsList);
if (delimiter == null)
{
listNonTerminal.Rule = listMember | listNonTerminal + listMember;
}
else
{
listNonTerminal.Rule = listMember | listNonTerminal + delimiter + listMember;
}
return(listNonTerminal.Rule);
}
public BnfExpression MakeStarRule(NonTerminal listNonTerminal, BnfTerm delimiter, BnfTerm listMember)
{
if (delimiter == null)
{
//it is much simpler case
listNonTerminal.SetOption(TermOptions.IsList);
listNonTerminal.Rule = Empty | listNonTerminal + listMember;
return(listNonTerminal.Rule);
}
NonTerminal tmp = new NonTerminal(listMember.Name + "+");
MakePlusRule(tmp, delimiter, listMember);
listNonTerminal.Rule = Empty | tmp;
listNonTerminal.SetOption(TermOptions.IsStarList);
return(listNonTerminal.Rule);
}
}//method
private AstNode CreateNode(ActionRecord reduceAction, SourceSpan sourceSpan, AstNodeList childNodes)
{
NonTerminal nt = reduceAction.NonTerminal;
AstNode result;
AstNodeArgs args = new AstNodeArgs(nt, _context, sourceSpan, childNodes);
result = nt.InvokeNodeCreator(args);
if (result != null)
{
return(result);
}
Type defaultNodeType = _context.Compiler.Grammar.DefaultNodeType;
Type ntNodeType = nt.NodeType ?? defaultNodeType ?? typeof(AstNode);
// Check if NonTerminal is a list
// List nodes are produced by .Plus() or .Star() methods of BnfElement
// In this case, we have a left-recursive list formation production:
// ntList -> ntList + delim? + ntElem
// We check if we have already created the list node for ntList (in the first child);
// if yes, we use this child as a result directly, without creating new list node.
// The other incoming child - the last one - is a new list member;
// we simply add it to child list of the result ntList node. Optional "delim" node is simply thrown away.
bool isList = nt.IsSet(TermOptions.IsList);
if (isList && childNodes.Count > 1 && childNodes[0].Term == nt)
{
result = childNodes[0];
AstNode newChild = childNodes[childNodes.Count - 1];
newChild.Parent = result;
result.ChildNodes.Add(newChild);
return(result);
}
//Check for StarList produced by MakeStarList; in this case the production is: ntList -> Empty | Elem+
// where Elem+ is non-empty list of elements. The child list we are actually interested in is one-level lower
if (nt.IsSet(TermOptions.IsStarList) && childNodes.Count == 1)
{
childNodes = childNodes[0].ChildNodes;
}
// Check for "node-bubbling" case. For identity productions like
// A -> B
// the child node B is usually a subclass of node A,
// so child node B can be used directly in place of the A. So we simply return child node as a result.
// TODO: probably need a grammar option to enable/disable this behavior explicitly
if (!isList && !nt.IsSet(TermOptions.IsPunctuation) && childNodes.Count == 1)
{
Type childNodeType = childNodes[0].Term.NodeType ?? defaultNodeType ?? typeof(AstNode);
if (childNodeType == ntNodeType || childNodeType.IsSubclassOf(ntNodeType))
{
return(childNodes[0]);
}
}
// Try using Grammar's CreateNode method
result = Data.Grammar.CreateNode(_context, reduceAction, sourceSpan, childNodes);
if (result == null)
{
//Finally create node directly. For perf reasons we try using "new" for AstNode type (faster), and
// activator for all custom types (slower)
if (ntNodeType == typeof(AstNode))
{
result = new AstNode(args);
}
else
#if PocketPC || SILVERLIGHT
{
ConstructorInfo ctor = ntNodeType.GetConstructor(new Type[] { typeof(AstNodeArgs) });
if (ctor == null)
{
throw new Exception("Failed to located constructor: " + ntNodeType.ToString() + "(AstNodeArgs args)");
}
result = (AstNode)ctor.Invoke(new object[] { args });
}
#else
{
result = (AstNode)Activator.CreateInstance(ntNodeType, args);
}
#endif
}
if (result != null)
{
nt.OnNodeCreated(result);
}
return(result);
}
