public static BnfExpression MakePlusRule(NonTerminal listNonTerminal, BnfTerm delimiter, BnfTerm listMember)
{
if (delimiter == null)
{
listNonTerminal.Rule = listMember | listNonTerminal + listMember;
}
else
{
listNonTerminal.Rule = listMember | listNonTerminal + delimiter + listMember;
}
listNonTerminal.SetFlag(TermFlags.IsList);
return(listNonTerminal.Rule);
}
private void CollectTermsRecursive(BnfTerm term)
{
if (_grammarData.AllTerms.Contains(term))
{
return;
}
_grammarData.AllTerms.Add(term);
var nt = term as NonTerminal;
if (nt == null)
{
return;
}
if (string.IsNullOrEmpty(nt.Name))
{
if (!string.IsNullOrEmpty(nt.Rule?.Name))
{
nt.Name = nt.Rule.Name;
}
else
{
nt.Name = "Unnamed" + _unnamedCount++;
}
}
if (nt.Rule == null)
{
_language.Errors.AddAndThrow(GrammarErrorLevel.Error, null, Resources.ErrNtRuleIsNull, nt.Name);
}
//check all child elements
foreach (var elemList in nt.Rule.Data)
{
for (var i = 0; i < elemList.Count; i++)
{
var child = elemList[i];
if (child == null)
{
_language.Errors.Add(GrammarErrorLevel.Error, null, Resources.ErrRuleContainsNull, nt.Name, i);
continue;
}
//Check for nested expression - convert to non-terminal
if (child is BnfExpression expr)
{
child = new NonTerminal(null, expr);
elemList[i] = child;
}
CollectTermsRecursive(child);
}
}
}
public LRItemSet SelectByCurrent(BnfTerm current)
{
var result = new LRItemSet();
foreach (var item in this)
{
if (item.Core.Current == current)
{
result.Add(item);
}
}
return(result);
}
public static BnfExpression MakePlusRule(NonTerminal listNonTerminal, BnfTerm delimiter, BnfTerm listMember, TermListOptions options)
{
bool allowTrailingDelimiter = (options & TermListOptions.AllowTrailingDelimiter) != 0;
if (delimiter == null || !allowTrailingDelimiter)
{
return(MakePlusRule(listNonTerminal, delimiter, listMember));
}
//create plus list
var plusList = new NonTerminal(listMember.Name + "+");
plusList.Rule = MakePlusRule(listNonTerminal, delimiter, listMember);
listNonTerminal.Rule = plusList | plusList + delimiter;
listNonTerminal.SetFlag(TermFlags.IsListContainer);
return(listNonTerminal.Rule);
}
//Pipe/Alternative
//New version proposed by the codeplex user bdaugherty
internal static BnfExpression Op_Pipe(BnfTerm term1, BnfTerm term2)
{
BnfExpression expr1 = term1 as BnfExpression;
if (expr1 == null)
{
expr1 = new BnfExpression(term1);
}
BnfExpression expr2 = term2 as BnfExpression;
if (expr2 == null)
{
expr2 = new BnfExpression(term2);
}
expr1.Data.AddRange(expr2.Data);
return(expr1);
}
private ParserAction FindErrorShiftActionInStack(BnfTerm exitTerm)
{
while (Context.ParserStack.Count >= 1)
{
ParserAction errorShiftAction;
if (Context.CurrentParserState.Actions.TryGetValue(exitTerm, out errorShiftAction))
{
return(errorShiftAction);
}
//pop next state from stack
if (Context.ParserStack.Count == 1)
{
return(null); //don't pop the initial state
}
Context.ParserStack.Pop();
Context.CurrentParserState = Context.ParserStack.Top.State;
}
return(null);
}
protected BnfExpression MakeListRule(NonTerminal list, BnfTerm delimiter, BnfTerm listMember, TermListOptions options = TermListOptions.PlusList)
{
//If it is a star-list (allows empty), then we first build plus-list
var isPlusList = !options.IsSet(TermListOptions.AllowEmpty);
var allowTrailingDelim = options.IsSet(TermListOptions.AllowTrailingDelimiter) && delimiter != null;
//"plusList" is the list for which we will construct expression - it is either extra plus-list or original list.
// In the former case (extra plus-list) we will use it later to construct expression for list
NonTerminal plusList = isPlusList ? list : new NonTerminal(listMember.Name + "+");
plusList.SetFlag(TermFlags.IsList);
plusList.Rule = plusList; // rule => list
if (delimiter != null)
{
plusList.Rule += delimiter; // rule => list + delim
}
if (options.IsSet(TermListOptions.AddPreferShiftHint))
{
plusList.Rule += PreferShiftHere(); // rule => list + delim + PreferShiftHere()
}
plusList.Rule += listMember; // rule => list + delim + PreferShiftHere() + elem
plusList.Rule |= listMember; // rule => list + delim + PreferShiftHere() + elem | elem
if (isPlusList)
{
// if we build plus list - we're almost done; plusList == list
// add trailing delimiter if necessary; for star list we'll add it to final expression
if (allowTrailingDelim)
{
plusList.Rule |= list + delimiter; // rule => list + delim + PreferShiftHere() + elem | elem | list + delim
}
}
else
{
// Setup list.Rule using plus-list we just created
list.Rule = Empty | plusList;
if (allowTrailingDelim)
{
list.Rule |= plusList + delimiter | delimiter;
}
plusList.SetFlag(TermFlags.NoAstNode);
list.SetFlag(TermFlags.IsListContainer); //indicates that real list is one level lower
}
return(list.Rule);
}//method
//Find an LR item without hints compatible with term (either shift on term or reduce with term as lookahead);
// this item without hints would become our default. We assume that other items have hints, and when conditions
// on all these hints fail, we chose this remaining item without hints.
private ParserAction FindDefaultAction(ParserState state, BnfTerm term)
{
//First check reduce items
var reduceItems = state.BuilderData.ReduceItems.SelectByLookahead(term as Terminal);
foreach (var item in reduceItems)
{
if (item.Core.Hints.Count == 0)
{
return(ReduceParserAction.Create(item.Core.Production));
}
}
var shiftItem = state.BuilderData.ShiftItems.SelectByCurrent(term).FirstOrDefault();
if (shiftItem != null)
{
return(new ShiftParserAction(shiftItem));
}
//if everything failed, returned first reduce item
return(null);
}
protected BnfExpression MakeListRule(NonTerminal list, BnfTerm delimiter, BnfTerm listMember, TermListOptions options = TermListOptions.PlusList)
{
//If it is a star-list (allows empty), then we first build plus-list
var isStarList = options.IsSet(TermListOptions.AllowEmpty);
NonTerminal plusList = isStarList ? new NonTerminal(listMember.Name + "+") : list;
//"list" is the real list for which we will construct expression - it is either extra plus-list or original listNonTerminal.
// In the latter case we will use it later to construct expression for listNonTerminal
plusList.Rule = plusList; // rule => list
if (delimiter != null)
{
plusList.Rule += delimiter; // rule => list + delim
}
if (options.IsSet(TermListOptions.AddPreferShiftHint))
{
plusList.Rule += PreferShiftHere(); // rule => list + delim + PreferShiftHere()
}
plusList.Rule += listMember; // rule => list + delim + PreferShiftHere() + elem
plusList.Rule |= listMember; // rule => list + delim + PreferShiftHere() + elem | elem
//trailing delimiter
if (options.IsSet(TermListOptions.AllowTrailingDelimiter) & delimiter != null)
{
plusList.Rule |= list + delimiter; // => list + delim + PreferShiftHere() + elem | elem | list + delim
}
// set Rule value
plusList.SetFlag(TermFlags.IsList);
//If we do not use exra list - we're done, return list.Rule
if (plusList == list)
{
return(list.Rule);
}
// Let's setup listNonTerminal.Rule using plus-list we just created
//If we are here, TermListOptions.AllowEmpty is set, so we have star-list
list.Rule = Empty | plusList;
plusList.SetFlag(TermFlags.NoAstNode);
list.SetFlag(TermFlags.IsListContainer); //indicates that real list is one level lower
return(list.Rule);
}//method
public static BnfExpression MakeStarRule(NonTerminal listNonTerminal, BnfTerm delimiter, BnfTerm listMember, TermListOptions options) {
bool allowTrailingDelimiter = (options & TermListOptions.AllowTrailingDelimiter) != 0;
if (delimiter == null) {
//it is much simpler case
listNonTerminal.SetFlag(TermFlags.IsList);
listNonTerminal.Rule = _currentGrammar.Empty | listNonTerminal + listMember;
return listNonTerminal.Rule;
}
//Note that deceptively simple version of the star-rule
// Elem* -> Empty | Elem | Elem* + delim + Elem
// does not work when you have delimiters. This simple version allows lists starting with delimiters -
// which is wrong. The correct formula is to first define "Elem+"-list, and then define "Elem*" list
// as "Elem* -> Empty|Elem+"
NonTerminal plusList = new NonTerminal(listMember.Name + "+");
plusList.Rule = MakePlusRule(plusList, delimiter, listMember);
plusList.SetFlag(TermFlags.NoAstNode); //to allow it to have AstNodeType not assigned
if (allowTrailingDelimiter)
listNonTerminal.Rule = _currentGrammar.Empty | plusList | plusList + delimiter;
else
listNonTerminal.Rule = _currentGrammar.Empty | plusList;
listNonTerminal.SetFlag(TermFlags.IsListContainer);
return listNonTerminal.Rule;
}
public BnfExpression MakePlusRule(NonTerminal listNonTerminal, BnfTerm delimiter, BnfTerm listMember)
{
return(MakeListRule(listNonTerminal, delimiter, listMember));
}
public static BnfExpression MakePlusRule(NonTerminal listNonTerminal, BnfTerm listMember)
{
return(MakePlusRule(listNonTerminal, null, listMember));
}
}//method
private void ExecuteShiftTemp(BnfTerm term, ParserAction action)
{
Context.ParserStack.Push(new ParseTreeNode(term), action.NewState);
Context.CurrentParserState = action.NewState;
}
public BnfExpression(BnfTerm element) : this()
{
Data[0].Add(element);
}
public static BnfExpression MakeStarRule(NonTerminal listNonTerminal, BnfTerm listMember) {
return MakeStarRule(listNonTerminal, null, listMember, TermListOptions.None);
}
internal ParserState State; //used by parser to store current state when node is pushed into the parser stack
public ParseTreeNode(BnfTerm term)
{
Term = term;
}
public BnfExpression MakeStarRule(NonTerminal listNonTerminal, BnfTerm listMember)
{
return(MakeListRule(listNonTerminal, null, listMember, TermListOptions.StarList));
}
public ShiftParserAction(BnfTerm term, ParserState newState)
{
Term = term;
NewState = newState;
}
public BnfExpression MakeStarRule(NonTerminal listNonTerminal, BnfTerm delimiter, BnfTerm listMember, TermListOptions options)
{
return(MakeListRule(listNonTerminal, delimiter, listMember, options | TermListOptions.StarList));
}
public ParseTreeNode(NonTerminal term, SourceSpan span) : this()
{
Term = term;
Span = span;
}
public ParserState GetNextState(BnfTerm shiftTerm)
{
var shift = ShiftItems.FirstOrDefault(item => item.Core.Current == shiftTerm);
return(shift?.ShiftedItem.State);
}
public static BnfExpression MakeStarRule(NonTerminal listNonTerminal, BnfTerm delimiter, BnfTerm listMember)
{
return(MakeStarRule(listNonTerminal, delimiter, listMember, TermListOptions.None));
}
public ParseTreeNode(ParseTreeNode clone) : this(clone.State)
{
Term = clone.Term;
Tokens = clone.Tokens;
}
