parser.cs

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using System.Collections;
using System.Text;
using System;
using System.Reflection;

namespace at.jku.ssw.Coco {
	
	
	
	public class Parser {
		const int maxT = 42;
		
		const bool T = true;
		const bool x = false;
		const int minErrDist = 2;
		const string errMsgFormat = "-- line {0} col {1}: {2}";  // 0=line, 1=column, 2=text
		
		static Token t;                   // last recognized token
		static Token la;                  // lookahead token
		static int errDist = minErrDist;
		
		const int id = 0;
		const int str = 1;
		
		static bool genScanner;
		
		/*-------------------------------------------------------------------------*/
		
		
		
		static void SynErr (int n) {
			if (errDist >= minErrDist) Errors.SynErr(la.line, la.col, n);
			errDist = 0;
		}
		
		public static void SemErr (string msg) {
			if (errDist >= minErrDist) Errors.Error(t.line, t.col, msg);
			errDist = 0;
		}
		
		static void Get () {
			for (;;) {
				t = la;
				la = Scanner.Scan();
				if (la.kind <= maxT) { ++errDist; break; }  /* ML return changed to break */
				if (la.kind == 43) {
					Tab.SetDDT(la.val);
				}
				
				la = t;
			}
		}
		
		static void Expect (int n) {
			if (la.kind==n) Get(); else { SynErr(n); }
		}
		
		static bool StartOf (int s) {
			return set[s, la.kind];
		}
		
		static void ExpectWeak (int n, int follow) {
			if (la.kind == n) Get();
			else {
				SynErr(n);
				while (!StartOf(follow)) Get();
			}
		}
		
		static bool WeakSeparator (int n, int syFol, int repFol) {
			bool[] s = new bool[maxT+1];
			if (la.kind == n) { Get(); return true; }
			else if (StartOf(repFol)) return false;
			else {
				for (int i=0; i <= maxT; i++) {
					s[i] = set[syFol, i] || set[repFol, i] || set[0, i];
				}
				SynErr(n);
				while (!s[la.kind]) Get();
				return StartOf(syFol);
			}
		}
		
		static void Coco() {
			Symbol sym; Graph g; string gramName;
			if (la.kind == 40) {
				UsingDecl(out ParserGen.usingPos);
			}
			Expect(6);
			int gramLine = t.line;
			genScanner = true;
			bool ok = true;
			Tab.ignored = null;
			
			Expect(1);
			gramName = t.val;
			int beg = la.pos;
			
			while (StartOf(1)) {
				Get();
			}
			Tab.semDeclPos = new Position(beg, la.pos-beg, 0);
			while (StartOf(2)) {
				Declaration();
			}
			while (!(la.kind == 0 || la.kind == 7)) {SynErr(43); Get();}
			Expect(7);
			if (genScanner) DFA.MakeDeterministic();
			Graph.DeleteNodes();
			
			while (la.kind == 1) {
				Get();
				sym = Symbol.Find(t.val);
				bool undef = sym == null;
				if (undef) sym = new Symbol(Node.nt, t.val, t.line);
				else {
					if (sym.typ == Node.nt) {
						if (sym.graph != null) SemErr("name declared twice");
					} else SemErr("this symbol kind not allowed on left side of production");
					sym.line = t.line;
				}
				bool noAttrs = sym.attrPos == null;
				sym.attrPos = null;
				
				if (la.kind == 24) {
					AttrDecl(sym);
				}
				if (!undef)
					if (noAttrs != (sym.attrPos == null))
					SemErr("attribute mismatch between declaration and use of this symbol");
				
				if (la.kind == 38) {
					SemText(out sym.semPos);
				}
				ExpectWeak(8, 3);
				Expression(out g);
				sym.graph = g.l;
				Graph.Finish(g);
				
				ExpectWeak(9, 4);
			}
			Expect(10);
			Expect(1);
			if (gramName != t.val)
				SemErr("name does not match grammar name");
			Tab.gramSy = Symbol.Find(gramName);
			if (Tab.gramSy == null)
				SemErr("missing production for grammar name");
			else {
				sym = Tab.gramSy;
				if (sym.attrPos != null)
					SemErr("grammar symbol must not have attributes");
			}
			Tab.noSym = new Symbol(Node.t, "???", 0); // noSym gets highest number
			Tab.SetupAnys();
			Tab.RenumberPragmas();
			if (Tab.ddt[2]) Node.PrintNodes();
			if (Errors.count == 0) {
				Console.WriteLine("checking");
				Tab.CompSymbolSets();
				ok = ok && Tab.GrammarOk();
				if (Tab.ddt[7]) Tab.XRef();
				if (ok) {
					Console.Write("parser");
					ParserGen.WriteParser();
					if (genScanner) {
						Console.Write(" + scanner");
						DFA.WriteScanner();
						if (Tab.ddt[0]) DFA.PrintStates();
					}
					Console.WriteLine(" generated");
					if (Tab.ddt[8]) ParserGen.WriteStatistics();
				}
			}
			if (Tab.ddt[6]) Tab.PrintSymbolTable();
			
			Expect(9);
		}
		
		static void UsingDecl(out Position pos) {
			Expect(40);
			int beg = t.pos;
			while (StartOf(5)) {
				Get();
			}
			Expect(41);
			int end = t.pos;
			while (la.kind == 40) {
				Get();
				while (StartOf(5)) {
					Get();
				}
				Expect(41);
				end = t.pos;
			}
			pos = new Position(beg, end - beg + 1, 0);
		}
		
		static void Declaration() {
			Graph g1, g2; bool nested = false;
			switch (la.kind) {
					case 11: {
						Get();
						while (la.kind == 1) {
							SetDecl();
						}
						break;
					}
					case 12: {
						Get();
						while (la.kind == 1 || la.kind == 3 || la.kind == 5) {
							TokenDecl(Node.t);
						}
						break;
					}
					case 13: {
						Get();
						while (la.kind == 1 || la.kind == 3 || la.kind == 5) {
							TokenDecl(Node.pr);
						}
						break;
					}
					case 14: {
						Get();
						Expect(15);
						TokenExpr(out g1);
						Expect(16);
						TokenExpr(out g2);
						if (la.kind == 17) {
							Get();
							nested = true;
						} else if (StartOf(6)) {
							nested = false;
						} else SynErr(44);
						new Comment(g1.l, g2.l, nested);
						break;
					}
					case 18: {
						Get();
						Set(out Tab.ignored);
						Tab.ignored[' '] = true; /* ' ' is always ignored */
						if (Tab.ignored[0]) SemErr("may not ignore \'\\0\'");
						break;
					}
					case 19: {
						Get();
						Symbol.tokenNames = new Hashtable();
						while (la.kind == 1 || la.kind == 3) {
							if (la.kind == 3) {
								Get();
							} else {
								Get();
							}
							string key = t.val;
							Expect(8);
							Expect(1);
							string val = t.val; Symbol.tokenNames.Add(key, val);
						}
						break;
					}
					default: SynErr(45); break;
			}
		}
		
		static void AttrDecl(Symbol sym) {
			Expect(24);
			int beg = la.pos; int col = la.col;
			while (StartOf(7)) {
				if (la.kind == 24) {
					AttrDecl(sym);
				} else if (StartOf(8)) {
					Get();
				} else {
					Get();
					SemErr("bad string in semantic action");
				}
			}
			Expect(25);
			sym.attrPos = new Position(beg, t.pos - beg, col);
		}
		
		static void SemText(out Position pos) {
			Expect(38);
			int beg = la.pos; int col = la.col;
			while (StartOf(9)) {
				if (StartOf(10)) {
					Get();
				} else if (la.kind == 4) {
					Get();
					SemErr("bad string in semantic action");
				} else {
					Get();
					SemErr("missing end of previous semantic action");
				}
			}
			Expect(39);
			pos = new Position(beg, t.pos - beg, col);
		}
		
		static void Expression(out Graph g) {
			Graph g2;
			Term(out g);
			bool first = true;
			while (WeakSeparator(26,11,12) ) {
				Term(out g2);
				if (first) { Graph.MakeFirstAlt(g); first = false; }
				Graph.MakeAlternative(g, g2);
				
			}
		}
		
		static void SetDecl() {
			BitArray s;
			Expect(1);
			string name = t.val;
			CharClass c = CharClass.Find(name);
			if (c != null) SemErr("name declared twice");
			
			Expect(8);
			Set(out s);
			if (Sets.Elements(s) == 0) SemErr("character set must not be empty");
			c = new CharClass(name, s);
			
			Expect(9);
		}
		
		static void TokenDecl(int typ) {
			string name; int kind; Symbol sym; Graph g;
			Sym(out name, out kind);
			sym = Symbol.Find(name);
			if (sym != null) SemErr("name declared twice");
			else {
				sym = new Symbol(typ, name, t.line);
				sym.tokenKind = Symbol.classToken;
			}
			
			while (!(StartOf(13))) {SynErr(46); Get();}
			if (la.kind == 8) {
				Get();
				TokenExpr(out g);
				Expect(9);
				if (kind != id) SemErr("a literal must not be declared with a structure");
				Graph.Finish(g);
				DFA.ConvertToStates(g.l, sym);
				
			} else if (la.kind == 9) {
				Get();
				if (typ != Node.rslv) SemErr("resolver is only allowed in RESOLVERS section");
			} else if (StartOf(14)) {
				if (kind == id) genScanner = false;
				else DFA.MatchLiteral(sym);
				
			} else SynErr(47);
			if (la.kind == 38) {
				SemText(out sym.semPos);
				if (typ == Node.t) SemErr("semantic action not allowed here");
			} else if (StartOf(15)) {
				if (typ == Node.rslv) SemErr("resolvers must have a semantic action");
			} else SynErr(48);
		}
		
		static void TokenExpr(out Graph g) {
			Graph g2;
			TokenTerm(out g);
			bool first = true;
			while (WeakSeparator(26,16,17) ) {
				TokenTerm(out g2);
				if (first) { Graph.MakeFirstAlt(g); first = false; }
				Graph.MakeAlternative(g, g2);
				
			}
		}
		
		static void Set(out BitArray s) {
			BitArray s2;
			SimSet(out s);
			while (la.kind == 20 || la.kind == 21) {
				if (la.kind == 20) {
					Get();
					SimSet(out s2);
					s.Or(s2);
				} else {
					Get();