private static RegularGrammar validateProductions(string[] nt, RegularGrammar rg)
{
TextScanner vnScan = null;
string vn = "";
string prod = "";
HashSet <string> pr = new HashSet <string>();
bool isDefined = false;
for (int i = 0; i < nt.Length; i++)
{
prod = nt[i];
vnScan = new TextScanner(prod);
vnScan.UseDelimiter("->");
bool valid;
if (vnScan.HasNext())
{
vn = vnScan.Next();
valid = rg.productions.TryGetValue(vn[0], out pr);
if (pr == null)
{
pr = new HashSet <string>();
}
if (vn.Length > 1 || char.IsLower(vn[0]) || !char.IsLetter(vn[0]))
{
rg.vn.Clear();
vnScan.Close();
}
else
{
rg.vn.Add(vn[0]);
if (!isDefined)
{
rg.s = vn[0];
isDefined = true;
}
if (!validateProduction(vn[0], prod, pr, rg))
{
rg.vn.Clear();
vnScan.Close();
return(null);
}
}
}
vnScan.Close();
}
return(rg);
}
private static bool validateProduction(char vn, string productions, HashSet <string> prodList, RegularGrammar rg)
{
string prod = productions.Substring(productions.IndexOf("->") + 2);
int prodLenght = 0;
char first, second;
prodScan = new TextScanner(prod);
prodScan.UseDelimiter("[|]");
if (prod.Length < 1)
{
prodScan.Close();;
return(false);
}
while (prodScan.HasNext())
{
prod = prodScan.Next();
prodLenght = prod.Length;
if (prodLenght < 1 || prodLenght > 2)
{
prodScan.Close();
return(false);
}
else
{
first = prod[0];
if (char.IsUpper(first))
{
prodScan.Close();
return(false);
}
if (char.IsDigit(first) || char.IsLetter(first))
{
rg.vt.Add(first);
}
if (prodLenght == 2)
{
second = prod[1];
if (char.IsUpper(first))
{
prodScan.Close();
return(false);
}
if (char.IsLetter(second) || char.IsDigit(second))
{
prodScan.Close();
return(false);
}
if (first == '&' || second == '&')
{
prodScan.Close();
return(false);
}
if (second == rg.s && rg.vt.Contains('&'))
{
prodScan.Close();
return(false);
}
rg.vn.Add(second);
prodList.Add(prod);
rg.productions.Add(vn, prodList);
}
else
{
if (char.IsUpper(first))
{
prodScan.Close();
return(false);
}
if (first == '&')
{
rg.vt.Add(first);
if (vn != rg.s)
{
prodScan.Close();
return(false);
}
if (rg.productions.Values.Any()) //rever!
{
prodScan.Close();
return(false);
}
}
prodList.Add(prod);
rg.productions.Add(vn, prodList);
}
}
}
prodScan.Close();
return(true);
}
/// <summary>
/// Initializes a new instance of the <see cref="PeekStream"/> class.
/// </summary>
/// <param name="textScanner">The text scanner.</param>
public PeekStream(TextScanner textScanner)
{
this.textReader = textScanner.textReader;
this.unconsumedChars = textScanner.unconsumedChars;
}
