private CflParse Read(ref string input)
{
if (!string.IsNullOrEmpty(input))
{
var match = null as Tuple <string, string[]>;
var space = null as Match;
var sofar = input;
var lexicals =
!(space = Grammar.WhiteSpace.Match(sofar)).Success ?
(match = Grammar.Lexicon.Match(sofar)).Item2
:
null;
if (lexicals != null)
{
if (lexicals.Length > 0)
{
var productions = new CnfProductions(Grammar, lexicals);
var value = match.Item1;
input = input.Substring(value.Length);
return(new CflParse(productions, value));
}
else
{
input = null;
return(Error(sofar));
}
}
else
{
input = input.Substring(space.Length);
return(WhiteSpace(space.Value));
}
}
return(null);
}
public CnfProductions Lookup(CnfProductions left, CnfProductions right)
{
var reductions =
Binaries.
Aggregate
(
new CnfProductions(this),
(found, production)
=>
{
if (left.Contains(production.Rhs1) && right.Contains(production.Rhs2))
{
found.Add(production.Lhs);
}
return(found);
}
);
return((reductions != null) && (reductions.Count > 0) ? reductions : null);
}
public CflParse(CnfProductions productions, CflParse left, CflParse right)
: base(left, right)
{
Productions = productions;
}
public CflParse(CnfProductions productions, string token)
: this(productions, null, null)
{
Value = token;
}
public CnfGrammar()
{
Productions = new Dictionary <string, CnfProduction>();
Error = new CnfProductions(this, "Error");
WhiteSpace = GetInsignificantWhiteSpace();
}