static string ItemToString(ProductionItem item, bool doLA)
{
int lhsLength;
List <string> list = new List <string>();
System.Text.StringBuilder builder = new System.Text.StringBuilder();
builder.AppendFormat("{0} {1}: ", item.production.num, item.production.lhs);
lhsLength = builder.Length;
for (int i = 0; i < item.production.rhs.Count; i++)
{
if (i == item.pos)
{
list.Add(".");
}
list.Add(item.production.rhs[i].ToString());
}
if (item.pos == item.production.rhs.Count)
{
list.Add(".");
}
builder.Append(ListUtilities.GetStringFromList(list, " ", lhsLength + 6));
if (item.LA != null && doLA)
{
builder.AppendLine();
builder.AppendFormat("\t-lookahead: {{ {0} }}", ListUtilities.GetStringFromList(item.LA, ", ", 16));
}
return(builder.ToString());
}
public override string ToString()
{
StringBuilder builder = new StringBuilder();
builder.AppendFormat("{0} {1}: ", production.num, production.lhs);
for (int i = 0; i < production.rhs.Count; i++)
{
if (i == pos)
{
builder.Append(". ");
}
builder.AppendFormat("{0} ", production.rhs[i]);
}
if (pos == production.rhs.Count)
{
builder.Append(".");
}
if (LA != null)
{
builder.AppendLine();
builder.AppendFormat("\t-lookahead: {0}", ListUtilities.GetStringFromList(LA, ", ", 16));
}
return(builder.ToString());
}
/// <summary>
/// This is the method that computes the shortest terminal
/// string sequence for each NonTerminal symbol. The immediate
/// guide is to find those NT that are non-terminating.
/// </summary>
void MarkTerminating()
{
bool changed = false;
int nonTerminatingCount = 0;
// This uses a naive algorithm that iterates until
// an iteration completes without changing anything.
do
{
changed = false;
nonTerminatingCount = 0;
foreach (KeyValuePair <string, NonTerminal> kvp in this.nonTerminals)
{
NonTerminal nonTerm = kvp.Value;
if (!nonTerm.terminating)
{
foreach (Production prod in nonTerm.productions)
{
if (ProductionTerminates(prod))
{
nonTerm.terminating = true;
changed = true;
}
}
if (!nonTerm.terminating)
{
nonTerminatingCount++;
}
}
}
} while (changed);
//
// Now produce some helpful diagnostics.
// We wish to find single NonTerminals that, if made
// terminating will fix up many, even all of the
// non-terminating NonTerminals that have been found.
//
if (nonTerminatingCount > 0)
{
List <NonTerminal> ntDependencies = BuildDependencyGraph();
hasNonTerminatingNonTerms = true;
handler.AddError(
5,
String.Format(CultureInfo.InvariantCulture, "There are {0} non-terminating NonTerminal Symbols{1} {{{2}}}",
nonTerminatingCount,
System.Environment.NewLine,
ListUtilities.GetStringFromList(ntDependencies)), null);
FindNonTerminatingSCC(ntDependencies); // Do some diagnosis
}
}
public override string ToString()
{
StringBuilder builder = new StringBuilder();
builder.AppendFormat("{0} -> ", lhs);
if (rhs.Count == 0)
{
builder.Append("/* empty */");
}
else
{
builder.Append(ListUtilities.GetStringFromList(rhs, ", ", builder.Length));
}
return(builder.ToString());
}
private void Walk(NonTerminal node, Stack <NonTerminal> stack, List <NonTerminal> fixes, ref int count)
{
count++;
stack.Push(node);
node.depth = count;
foreach (NonTerminal next in node.dependsOnList)
{
if (next.depth == 0)
{
Walk(next, stack, fixes, ref count);
}
if (next.depth < count)
{
node.depth = next.depth;
}
}
if (node.depth == count) // traversal leaving strongly connected component
{
// This algorithm is folklore. I have been using it since
// at least early 1980s in the Gardens Point compilers.
// I don't even remember where I learned it ... (kjg).
//
NonTerminal popped = stack.Pop();
popped.depth = finishMark;
if (popped != node)
{
List <NonTerminal> SCC = new List <NonTerminal>();
SCC.Add(popped);
do
{
popped = stack.Pop();
popped.depth = finishMark;
SCC.Add(popped);
}while (popped != node);
handler.AddWarning(150, String.Format(CultureInfo.InvariantCulture,
"The following {2} symbols form a non-terminating cycle {0}{{{1}}}",
System.Environment.NewLine,
ListUtilities.GetStringFromList(SCC),
SCC.Count), null);
//
// Check if termination of any single NonTerminal
// would eliminate the whole cycle of dependency.
//
SccExperiment(SCC, fixes);
}
}
count--;
}
static void DiagnoseState <T>(StreamWriter writer, AutomatonState state, Mapper <T, AutomatonState> map)
{
// List<T> statePath = ListUtilities.Map<T, AutomatonState>(state.statePath, map);
IEnumerable <T> statePath = ListUtilities.MapC <T, AutomatonState>(state.statePath, map);
IEnumerable <T> predList = ListUtilities.MapC <T, AutomatonState>(state.predecessors, map);
writer.WriteLine(" Shortest prefix: {0}", ListUtilities.GetStringFromList(state.shortestPrefix, " ", 8));
writer.WriteLine(" Shortest path: {0}", ListUtilities.GetStringFromList(statePath, "->", 19, (ListUtilities.BreakRule) 16));
writer.WriteLine(" Predecessors: {0}", ListUtilities.GetStringFromList(predList, ", ", 18, (ListUtilities.BreakRule) 16));
writer.Write(KernelToString(state));
if (state.conflicts != null)
{
writer.WriteLine();
writer.WriteLine(" <b>Conflicts in this state</b>");
foreach (Conflict conflict in state.conflicts)
{
conflict.HtmlReport(writer);
}
}
writer.WriteLine();
}
private void LeafPropagate(NonTerminal root, List <NonTerminal> thisTestConfig)
{
int count = 0;
bool changed = false;
do
{
count = 0;
changed = false;
foreach (NonTerminal nt in thisTestConfig)
{
if (!nt.terminating)
{
foreach (Production prod in nt.productions)
{
if (ProductionTerminates(prod))
{
nt.terminating = true;
changed = true;
}
}
if (!nt.terminating)
{
count++;
}
}
}
}while (changed);
List <NonTerminal> filtered = FilterTerminatingElements(thisTestConfig);
handler.AddWarning(151, String.Format(CultureInfo.InvariantCulture,
"Terminating {0} fixes the following size-{1} NonTerminal set{2}{{{3}}}",
root.ToString(),
filtered.Count,
System.Environment.NewLine,
ListUtilities.GetStringFromList(filtered)), null);
}
void WriteProductions(StreamWriter writer)
{
NonTerminal lhs = null;
string padding = "";
foreach (Production production in productions)
{
int lhsLength = 0;
if (production.lhs != lhs)
{
if (lhs != null) // ==> this is a change to a new LHS, write terminating ';'
{
writer.WriteLine("{0} {1};", indexSkip, padding);
}
lhsLength = production.lhs.ToString().Length;
padding = new string( ' ', lhsLength );
lhs = production.lhs;
writer.WriteLine();
writer.Write("{0} {1}: ", ProductionAnchor(production.num), lhs);
}
else
{
writer.Write("{0} {1}| ", ProductionAnchor(production.num), padding);
}
if (production.rhs.Count == 0)
{
writer.WriteLine("/* empty */");
}
else
{
writer.WriteLine(ListUtilities.GetStringFromList(production.rhs, " ", lhsLength + 12));
}
}
writer.Write("{0} {1};", indexSkip, padding);
writer.WriteLine();
}
