public static Grammar Transform(GrammarAnalysis grammar)
{
if (grammar.GrammarType < GrammarChomskyType.Type2)
throw new ArgumentException("Must be type 2 grammar", nameof(grammar));
bool containsEmptyWord;
var rules = new NormalizedRuleCollection(grammar.Grammar.Rules);
var repeat = true;
while (repeat)
{
repeat = false;
foreach (var rule in rules.GetRules().ToArray())
{
if (rule.WordToInsert.IsEmpty)
{
if (rule.WordToReplace == grammar.Grammar.StartSymbol)
containsEmptyWord = true;
foreach (var r2 in rules.GetRules().Where(r => r.WordToInsert.Contains(rule.WordToReplace)))
foreach (var w in ReplaceAllEx(r2.WordToInsert, rule.WordToReplace, Word.Empty))
rules.AddRule(new GrammarRule(r2.WordToReplace, w));
rules.RemoveRule(rule);
repeat = true;
}
}
}
repeat = true;
while (repeat)
{
repeat = false;
foreach (var rule in rules.GetRules().ToArray())
{
if (rule.WordToInsert.IsNonTerminalSymbol)
{
foreach (var r2 in rules.GetRules().Where(r => r.WordToReplace == rule.WordToInsert))
rules.AddRule(new GrammarRule(rule.WordToReplace, r2.WordToInsert));
rules.RemoveRule(rule);
repeat = true;
}
}
}
// TODO: Split A -> ABc to A -> AB', B' -> BC, C -> c
return new Grammar(grammar.Grammar.Symbols, grammar.Grammar.StartSymbol, rules.GetRules());
}
static void Main1(string[] args)
{
var input = new GrammarAnalysis(Grammar.Create("ab", 'S', File.ReadAllText("input.txt")));
var reference = new GrammarAnalysis(Grammar.Create("ab", 'S', File.ReadAllText("reference.txt")));
Console.WriteLine("Input Type: " + input.GrammarType);
Console.WriteLine("Reference Type: " + reference.GrammarType);
int len1 = 0;
int len2 = 0;
var words1 = new List<string>();
var words2 = new List<string>();
ThreadStart a = () =>
{
foreach (var w in input.Derive())
{
var word = w.Item1;
len1 = w.Item2;
if (word.IsTerminalWord)
{
Console.WriteLine(word);
lock (words1)
{
words1.Add(word.ToString());
}
}
}
};
ThreadStart b = () =>
{
foreach (var w in reference.Derive())
{
var word = w.Item1;
len2 = w.Item2;
if (word.IsTerminalWord)
{
lock (words2)
{
words2.Add(word.ToString());
}
}
}
};
int minLen = 0;
new Thread(a).Start();
new Thread(b).Start();
while (true)
{
Thread.Sleep(100);
var m = Math.Min(len1, len2) - 1;
if (m != minLen)
{
minLen = m;
lock (words1)
{
lock (words2)
{
Comparison<string> c = (w1, w2) =>
(w1.Length != w2.Length)
? w1.Length.CompareTo(w2.Length)
: String.Compare(w1, w2, StringComparison.Ordinal);
words1.Sort(c);
words2.Sort(c);
foreach (var word in words2.Where(w => w.Length <= minLen).ToArray())
{
words2.RemoveAt(0);
while (true)
{
var fst = words1.FirstOrDefault();
if (fst == null || c(word, fst) < 0)
{
Console.WriteLine("Word '" + word +
"' is not in input grammar, but should be");
break;
}
words1.RemoveAt(0);
if (fst == word)
break;
Console.WriteLine("Word '" + fst +
"' is in input grammar, but it should not");
}
}
Console.WriteLine("Cur len: " + m);
}
}
}
}
}
static void Main(string[] args)
{
var input = new GrammarAnalysis(Grammar.Create("ab", 'S', File.ReadAllText("input.txt")));
var transformedGrammar = ChomskyNormalform.Transform(input);
}
