public static LexerEngine.Lexer Generate(string filename)
{
if (!filename.Contains(".miniflex"))
{
throw new FileLoadException("File not supported");
}
var lexContent = File.ReadAllLines(filename);
try
{
var lexer = new LexerEngine.Lexer();
foreach (var line in lexContent)
{
var newMember = GetMember(line);
//Console.WriteLine("Added Token: {0} Rule {1}", newMember.Item1,@newMember.Item2);
lexer.AddDefinition(new TokenDefinition(newMember.Item1, new Regex(@newMember.Item2)));
}
return(lexer);
}
catch
{
return(null);
}
}
public LR1Table(Grammar g, string miniflex)
{
lexer = LexerGenerator.Generate(miniflex);
_grammar = g; //consider building a new grammar, not just stealing the pointer (as LL1).
_grammar.GenerateFirstAndFollow();
_terminalLookup = new Dictionary <Symbol, int>();
_gotoLookup = new Dictionary <Tuple <Symbol, int>, int>();
_lr1 = new LR1(g);
//Get terminal symbols from grammar
var terminals = (_grammar.Symbols.Where(x => x.IsTerminal())).ToArray();
var nonTerminals = (_grammar.Symbols.Where(x => x.IsNonTerminal())).ToArray();
_acceptanceState = _lr1.AutomataStates.Keys.Count - 1;
var maxState = _acceptanceState;
for (var i = 0; i < terminals.Length; i++)
{
_terminalLookup.Add(terminals[i], i);
}
_terminalLookup.Add(new Symbol(Symbol.SymTypes.EOS, "$"), terminals.Length); //add the end of string symbol
_table = new Action[_terminalLookup.Count, maxState + 1]; //generate Action lookUp table
//Construct the table with the provided automaton
for (var i = 0; i < maxState; i++)
{
var focusState = _lr1.AutomataStates[i]; //get the nth state
//set reduce Actions
var reduceRule = focusState.RuleToReduce;
if (reduceRule != null)
{
reduceRule.Caret = 0; //reset the caret
for (var j = 0; j < _grammar.ProductionRules.Count; j++)
{
if (!_grammar.ProductionRules[j].Equals(reduceRule))
{
continue;
}
foreach (var follow in g.FollowSets[focusState.Header.Header])
{
_table[_terminalLookup[follow], focusState.StateName] = new Action(ActionTypes.Reduce, j);
}
break;
}
}
//set shift Actions
foreach (var term in _terminalLookup.Keys.Where(term => focusState.PublicTransitions.ContainsKey(term)))
{
_table[_terminalLookup[term], focusState.StateName] = new Action(ActionTypes.Shift, focusState.PublicTransitions[term]);
}
//set goto lookup
foreach (var nonTerm in nonTerminals.Where(nonTerm => focusState.PublicTransitions.ContainsKey(nonTerm)))
{
_gotoLookup[new Tuple <Symbol, int>(nonTerm, focusState.StateName)] =
focusState.PublicTransitions[nonTerm];
}
}
}
