MaybeAdd() public method

public MaybeAdd ( ProdItem item ) : void
item ProdItem
return void
示例#1
0
 public void AddStartItems(ParseState pstate, SymbolSet follows)
 {
     for (int index = 0; index < this.m_prods.Count; ++index)
     {
         Production prod = (Production)this.m_prods[index];
         pstate.MaybeAdd(new ProdItem(prod, 0));
     }
 }
示例#2
0
 public void AddEntries()
 {
     for (ProdItemList prodItemList = this.m_items; prodItemList.m_pi != null; prodItemList = prodItemList.m_next)
     {
         ProdItem pi1 = prodItemList.m_pi;
         if (!pi1.m_done)
         {
             CSymbol csymbol = pi1.Next();
             if (csymbol != null && !pi1.IsReducingAction())
             {
                 ParseState parseState = new ParseState(this.m_sgen, csymbol);
                 parseState.MaybeAdd(new ProdItem(pi1.m_prod, pi1.m_pos + 1));
                 for (ProdItemList next = prodItemList.m_next; next != null && next.m_pi != null; next = next.m_next)
                 {
                     ProdItem pi2 = next.m_pi;
                     if (csymbol == pi2.Next())
                     {
                         parseState.MaybeAdd(new ProdItem(pi2.m_prod, pi2.m_pos + 1));
                         pi2.m_done = true;
                     }
                 }
                 if (!this.m_items.AtEnd)
                 {
                     if (csymbol.IsAction())
                     {
                         ParseState next = parseState.CheckExists();
                         foreach (CSymbol key in (IEnumerable)csymbol.m_follow.Keys)
                         {
                             if (key != this.m_sgen.m_symbols.EOFSymbol)
                             {
                                 this.GetTransition(key).m_next = new ParserShift((ParserAction)csymbol, next);
                             }
                         }
                     }
                     else
                     {
                         this.GetTransition(csymbol).m_next = new ParserShift((ParserAction)null, parseState.CheckExists());
                     }
                 }
             }
         }
     }
 }
示例#3
0
		public void AddEntries() 
		{
			ProdItemList pil;
			for (pil=m_items; pil.m_pi!=null; pil=pil.m_next) 
			{
				ProdItem item = pil.m_pi;
				if (item.m_done)
					continue;
				CSymbol s = item.Next();
				if (s==null || item.IsReducingAction())
					continue;
				// shift/goto action
				// Build a new parse state as target: we will check later to see if we need it
				ParseState p = new ParseState(m_sgen,s);
				// the new state should have at least the successor of this item
				p.MaybeAdd(new ProdItem(item.m_prod, item.m_pos+1));

				// check the rest of the items in this ParseState (leads to m_done for them)
				// looking for other items that allow this CSymbol to pass
				for (ProdItemList pil1=pil.m_next; pil1!=null && pil1.m_pi!=null; pil1=pil1.m_next) 
				{
					ProdItem another = pil1.m_pi;
					if (s==another.Next())
					{
						p.MaybeAdd(new ProdItem(another.m_prod, another.m_pos+1));
						another.m_done = true;
					}
				}

				if (!m_items.AtEnd) 
				{
					if (s.IsAction()) 
					{
						p = p.CheckExists();
						foreach (CSymbol f in s.m_follow.Keys)
							if (f!=m_sgen.m_symbols.EOFSymbol) 
							{
								Transition t = GetTransition(f);
//								if (t.m_next!=null)
//									m_sgen.Error(15,s.pos,String.Format("Action/Action or Action/Shift conflict on {0}",f.yytext));
								t.m_next = new ParserShift((ParserAction)s,p);
							}
					} 
					else 
					{ // we guarantee to make a nonzero entry in the parsetable
						GetTransition(s).m_next = new ParserShift(null, p.CheckExists());
					}
				}
			}
		}
示例#4
0
		public ObjectList m_prods = new ObjectList(); // Production:  productions with this symbol as left side
		public void AddStartItems(ParseState pstate,SymbolSet follows) 
		{ 
			for (int pos=0;pos<m_prods.Count;pos++)	
			{
				Production p = (Production)m_prods[pos];
				pstate.MaybeAdd(new ProdItem(p, 0));
			}
		}
示例#5
0
文件: pg.cs 项目: bbriggs/FieldWorks
	void _Create()
	{
		ptokens tks = new ptokens(erh);
		m_outname = "syntax";
		tks.m_sgen = this;
		m_lexer = tks;
		m_symbols.erh = erh;
		m_symbols.ClassInit(this);
		m_outname = "syntax";
		m_outFile.WriteLine("using System;using Tools;");
		Production special = new Production(this,m_symbols.Special);
		m_lexer.yytext = "error";
		CSymbol e = (new CSymbol(this)).Resolve();
		e.m_symtype = CSymbol.SymType.nonterminal;
		e.m_defined=true;
		// 1: INPUT
		// top-down parsing of script
		m_lexer.Start(m_inFile);
		m_tok = (TOKEN)m_lexer.Next();
		//Console.WriteLine("Token <{0}> {1}",m_tok.yytext,m_tok.GetType().Name);
		while (m_tok!=null)
			ParseProduction();
		// that's the end of the script
		if (!m_parserseen)
			Error(30,0,"no parser directive detected - possibly incorrect text encoding?");
		m_outFile.WriteLine(m_actions); // output the action function
		m_outFile.WriteLine("}  return null; }");
		special.AddToRhs(m_symbols.m_startSymbol);
		special.AddToRhs(m_symbols.EOFSymbol);
		// 2: PROCESSING
		Console.WriteLine("First");
		DoFirst();
		Console.WriteLine("Follow");
		DoFollow();
		Console.WriteLine("Parse Table");
		ParseState start = new ParseState(this,null);
		m_symbols.m_states[0] = start;
		start.MaybeAdd(new ProdItem(special,0));
		start.Closure();
		start.AddEntries();
		Transition tfinal = (Transition)start.m_transitions[m_symbols.m_startSymbol.yytext];
		ParserShift pe = tfinal.m_next;
		m_symbols.m_accept = pe.m_next;
		if (m_symbols.m_accept==null)
			m_symbols.erh.Error(new CSToolsFatalException(43,0,0,"","No accept state. ParserGenerator cannot continue."));
		// 2A: Reduce States for the LR(0) parser
		foreach (ParseState ps in m_symbols.m_states.Values)
			ps.ReduceStates();
		/*	if (m_showParser)
			{
				foreach (ParseState ps in m_symbols.m_states.Values)
				{
					ps.Print0();
					if (ps==m_symbols.m_accept)
						Console.WriteLine("    EOF  accept");
				}
			} */
		// 3: Compute Look-ahead sets
		if (m_lalrParser)
		{
			m_symbols.Transitions(new Builder(Transition.BuildDR));
			/*	if (m_showParser)
					m_symbols.PrintTransitions(new Func(Transition.DR),"DR"); */
			m_symbols.Transitions(new Builder(Transition.BuildReads));
			new Digraph(this,
				new Relation(Transition.reads),
				new Func(Transition.DR),
				new Func(Transition.Read),
				new AddToFunc(Transition.AddToRead)).Compute();
			// detect cycles in Read TBD
			/*	if (m_showParser)
					m_symbols.PrintTransitions(new Func(Transition.Read),"Read"); */
			m_symbols.Transitions(new Builder(Transition.BuildIncludes));
			m_symbols.Transitions(new Builder(Transition.BuildLookback));
			new Digraph(this,
				new Relation(Transition.includes),
				new Func(Transition.Read),
				new Func(Transition.Follow),
				new AddToFunc(Transition.AddToFollow)).Compute();
			// detect cycles for which Read is non empty TBD
			/*	if (m_showParser)
					m_symbols.PrintTransitions(new Func(Transition.Follow),"Follow"); */
			m_symbols.Transitions(new Builder(Transition.BuildLA));
		}
		// 5: OUTPUT
		// output the run-time ParsingInfo table
		Console.WriteLine("Building parse table");
		m_symbols.Transitions(new Builder(Transition.BuildParseTable));
		foreach (CSymbol v in m_symbols.symbols.Values)
		{
			if (v.m_symtype!=CSymbol.SymType.nodesymbol)
				continue;
			ParsingInfo pi = new ParsingInfo(v.yytext);
			CSymbol r = v;
			while (r.m_symtype==CSymbol.SymType.nodesymbol)
				r = r.m_refSymbol;
			if (m_symbols.symbolInfo[v.yytext]!=null)
				m_symbols.erh.Error(new CSToolsException(45,"Bad %node/%symbol hierarchy"));
			pi.m_parsetable = m_symbols.GetSymbolInfo(r.yytext).m_parsetable;
			m_symbols.symbolInfo[v.yytext] = pi;
		}
		Console.WriteLine("Writing the output file");
		m_outFile.WriteLine(@"/// <summary/>");
		m_outFile.WriteLine("public yy"+m_outname+"():base() { arr = new int[] { ");
		m_symbols.Emit(m_outFile);
		// output the class factories
		CSymbol s;
		Console.WriteLine("Class factories");
		IDictionaryEnumerator de = m_symbols.symbols.GetEnumerator();
		for (int pos = 0; pos<m_symbols.symbols.Count; pos++)
		{
			de.MoveNext();
			string str = (string)de.Key;
			s = (CSymbol)de.Value;
			if ((s==null) // might happen because of error recovery
				|| (s.m_symtype!=CSymbol.SymType.nonterminal && s.m_symtype!=CSymbol.SymType.nodesymbol))
				continue;
			//Console.WriteLine("{0} {1}",s.yytext,s.m_symtype);
			m_outFile.WriteLine("new Sfactory(this,\"{0}\",new SCreator({0}_factory));",str);
		}
		m_outFile.WriteLine("}");
		de.Reset();
		for (int pos = 0; pos<m_symbols.symbols.Count; pos++)
		{
			de.MoveNext();
			string str = (string)de.Key;
			s = (CSymbol)de.Value;
			if ((s==null) // might happen because of error recovery
				|| (s.m_symtype!=CSymbol.SymType.nonterminal && s.m_symtype!=CSymbol.SymType.nodesymbol))
				continue;
			//Console.WriteLine("{0} {1}",s.yytext,s.m_symtype);
			m_outFile.WriteLine(@"/// <summary/>");
			m_outFile.WriteLine("public static object "+str+"_factory(Parser yyp) { return new "+str+"(yyp); }");
		}
		m_outFile.WriteLine("}");
		m_outFile.WriteLine(@"/// <summary/>");
		m_outFile.WriteLine("public class "+m_outname+": Parser {");
		m_outFile.WriteLine(@"/// <summary/>");
		m_outFile.WriteLine("public "+m_outname+"():base(new yy"+m_outname+"(),new "+m_lexerClass+"()) {}");
		m_outFile.WriteLine(@"/// <summary/>");
		m_outFile.WriteLine("public "+m_outname+"(Symbols syms):base(syms,new "+m_lexerClass+"()) {}");
		m_outFile.WriteLine(@"/// <summary/>");
		m_outFile.WriteLine("public "+m_outname+"(Symbols syms,ErrorHandler erh):base(syms,new "+m_lexerClass+"(erh)) {}");
		m_outFile.WriteLine(m_actvars);
		m_outFile.WriteLine(" }");
		if (m_namespace)
			m_outFile.WriteLine("}");
		Console.WriteLine("Done");
		if (m_showParser)
		{
			foreach (ParseState ps in m_symbols.m_states.Values)
			{
				ps.Print();
				if (ps==m_symbols.m_accept)
					Console.WriteLine("    EOF  accept");
			}
		}
	}