package euler;

import java.net.URI;
import java.util.Enumeration;
import java.util.Vector;

import euler.output.ILogger;
import euler.output.Outputter;

/**
 * N3 parser.
 * 
 * @author Jos De Roo
 */

public class Parser {

	String str;		// N3 string
	int pos = 0;		// tokenizer position
	int line = 1;		// line counter
	Vector vt = null;	// quantified variables table
	Euler r = null;		// root Euler object
	String u = null;	// base URI of the RDF resource
	String ou = null;	// original base URI of the RDF resource
	int lv = 0;		// graph nesting level

	static final String ST = "{}[]()<>\"';,.^! \t\r\n\\\ufeff";
	static final String LOGa = "a";
	static final String LOGe = "=";
	static final String LOGi = "=>";
	static final String LOGt = "true";
	static final String LOGf = "false";
	static final String DPO = "<http://www.daml.org/2001/03/daml+oil";
	static final String ONT = "<http://www.w3.org/2001/10/daml+oil";
	static final String OWLUnambiguousProperty = "<http://www.w3.org/2002/07/owl#UnambiguousProperty>";
	static final String OWLUniqueProperty = "<http://www.w3.org/2002/07/owl#UniqueProperty>";
	static final String OWLdifferentIndividualFrom = "<http://www.w3.org/2002/07/owl#differentIndividualFrom>";
	static final String OWLequivalentTo = "<http://www.w3.org/2002/07/owl#equivalentTo>";
	static final String OWLsameClassAs = "<http://www.w3.org/2002/07/owl#sameClassAs>";
	static final String OWLsameIndividualAs = "<http://www.w3.org/2002/07/owl#sameIndividualAs>";
	static final String OWLsamePropertyAs = "<http://www.w3.org/2002/07/owl#samePropertyAs>";

	/**
	 * constructs an N3 parser
	 */
	public Parser() {
	}

	/**
	 * constructs an N3 parser
	 * 
	 * @param s
	 *            the N3 string
	 * @param vartab
	 *            quantified variables table
	 * @param root
	 *            Euler object
	 * @param uri
	 *            URI of the RDF resource
	 */
	public Parser(String s, Vector vartab, Euler root, String uri) {
		str = s;
		vt = vartab;
		r = root;
		u = uri;
		ou = u;
	}

	/**
	 * N3 triple parse method
	 * 
	 * @return Euler obj
	 */
	public Euler parse() {
		String nt = tokenize();
		if (nt == null)
			return null;
		return parse(true, nt);
	}

	/**
	 * N3 node parse method
	 * 
	 * @param nt
	 *            next token
	 * @return Euler obj
	 */
	public Euler parse(String nt) {
		return parse(false, nt);
	}

	Euler parse(boolean b, String nt) {
		Euler e = new Euler();
		try {
			if (u != null && u.startsWith("_:"))
				e.src = Euler.Ekb;
			else if (u != null) {
				e.src = "<" + u + ">";
				if (Euler.prologBChain)
					e.src = toQName(u + "#line_" + line);
				String es = (String) Euler.z.get(e.src);
				if (es != null)
					e.src = es;
				else
					Euler.z.put(e.src, e.src);
			}
			e.line = line;
			if (b) {
				if (nt == null)
					e.subj = null;
				else if (nt.equals("{")) {
					lv++;
					nt = tokenize();
					if (nt.equals("."))
						e.subj = parse(false, "{}");
					else
						e.subj = parse(true, nt);
					Euler el = e.subj;
					while (el.near != null)
						el = el.near;
					nt = tokenize();
					while (!nt.equals("}")) {
						el.near = parse(true, nt);
						while (el.near != null)
							el = el.near;
						nt = tokenize();
					}
					lv--;
				} else if (nt.equals("[")) {
					e.subj = parse(true, null);
					if (e.subj.verb == null)
						r.verb = ";]";
					nt = tokenize();
					if (!nt.equals("]"))
						System.err.println("** Parser error ** " + u + " line " + line + ": (p1) expecting ] at " + e + " but got " + nt);
					int cpos = pos;
					nt = tokenize();
					if (nt.equals(".")) {
						e.obj = parse(false, "");
						e.verb = "";
						e.cverb = "";
						e.bound = true;
						return e;
					} else
						pos = cpos;
				} else if (nt.equals("(")) {
					list(e);
					e.subj = e.obj;
					e.obj = null;
					int cpos = pos;
					nt = tokenize();
					if (nt.equals("."))
						return new Euler();
					else
						pos = cpos;
				} else {
					e.subj = parse(false, nt);
					if (nt.equals("this"))
						e.subj.verb = '<' + u + "#frag" + e.uid + '>';
				}
				path(e.subj);
				if (nt != null && nt.equals("@forAll")) {
					e.subj = parse(false, "this");
					nt = "log:forAll";
				} else if (nt != null && nt.equals("@forSome")) {
					e.subj = parse(false, "this");
					nt = "log:forSome";
				} else
					nt = tokenize();
			}
			if (nt == null || nt.equals(";")) {
				e.bound = true;
				return e;
			} else if (e.subj != null && nt.startsWith("_:")) {
				e.cverb = nt;
				if (!vt.contains(nt))
					vt.addElement(nt);
			} else if (nt.equals("[")) {
				String a = (Euler.prolog ? "?V" : "_:e") + e.uid;
				Euler ap = parse(true, a);
				e.cverb = a;
				if (ap.verb != null)
					r.verb = ";]";
				nt = tokenize();
				if (!nt.equals("]"))
					System.err.println("** Parser error ** " + u + " line " + line + ": (p2) expecting ] at " + e + " but got " + nt);
				if (ap.verb.equals(Euler.OWLsameAs)) {
					e.cverb = ap.obj.cverb;
					e.vv = true;
				} else
					e.near = ap;
			} else if (nt.equals("(")) {
				list(e);
				return e.obj;
			} else
				e.cverb = nt;
			if (e.cverb.endsWith("_@")) {
				e.vv = true;
				e.cverb = e.cverb.substring(0, e.cverb.length() - 2);
			}
			e.verb = e.cverb;
			if (e.verb.endsWith("@@"))
				e.verb = e.verb.substring(0, e.verb.length() - 2);
			if (r != null && e.verb.length() > 0 && e.verb.charAt(0) == '<') {
				String nsq = toURI(e.verb.substring(1, e.verb.length() - 1));
				e.verb = e.cverb = toQName(nsq);
			}
			if (e.subj != null && (e.cverb.equals("log:semantics") || e.cverb.equals("log:uri")))
				e.subj.cverb = e.subj.verb;
			String s1 = e.verb;
			String s2 = "";
			if (e.verb.indexOf('"') != -1) {
				s1 = e.verb.substring(0, e.verb.indexOf('"'));
				s2 = e.verb.substring(e.verb.indexOf('"'));
			}
			if (r != null && s1.length() > 0 && s1.indexOf(':') == -1 && s1.charAt(0) != '(' && s1.charAt(0) != '<'
					&& s1.charAt(0) != '[' && s1.charAt(0) != '_' && s1.charAt(0) != '"' && s1.charAt(0) != '?' && !r.isNumeral(s1)
					&& r.ext.kw.get(s1) == null)
				s1 = ":" + s1;
			if (r != null && s1.length() > 0 && s1.indexOf(':') != -1 && s1.charAt(0) != '(' && s1.charAt(0) != '<'
					&& s1.charAt(0) != '[' && s1.charAt(0) != '_' && s1.charAt(0) != '"') {
				String pf = s1.substring(0, s1.indexOf(':') + 1);
				String pg = (String) r.ext.nsp.get(pf);
				if (pg != null)
					pf = pg;
				String qf = (String) r.ext.ns.get(pf);
				if (qf == null) {
					System.err.println("** Parser warning ** " + ou + " line " + line + ": no @prefix " + pf + " found for " + s1
							+ ", taking <" + ou + "#>");
					qf = "<" + ou + "#>";
					r.ext.ns.put(pf, qf);
				}
				StringBuffer sb = new StringBuffer(pf);
				sb.append(e.cverb.substring(e.cverb.indexOf(':') + 1));
				e.cverb = sb.toString();
				sb = new StringBuffer(qf);
				sb.insert(sb.length() - 1, s1.substring(s1.indexOf(':') + 1));
				e.verb = sb.toString() + s2;
			} else if (u != null && s1.length() > 0 && s1.charAt(0) == '<' && s1.indexOf(':') == -1)
				e.verb = e.cverb = '<' + toURI(s1.substring(1, s1.length() - 1)) + '>' + s2;
			if (e.verb.length() > 0 && e.verb.charAt(0) == '?' && e.verb.indexOf('@') != -1 || e.verb.indexOf("\"@") != -1
					&& str.charAt(pos) != '^' && str.charAt(pos + 1) != '^') {
				r.ext.kw.put(e.verb.substring(e.verb.lastIndexOf('@') + 1), r);
				e.subj = parse(false, e.verb.substring(0, e.verb.lastIndexOf('@')));
				e.obj = parse(false, e.verb.substring(e.verb.lastIndexOf('@') + 1));
				e.verb = e.cverb = "@";
			}
			if (e.verb.equals(LOGa))
				e.verb = Euler.RDFtype;
			if (e.verb.equals(LOGe)) {
				e.verb = Euler.OWLsameAs;
				e.cverb = "owl:sameAs";
			}
			if (e.verb.equals(LOGi))
				e.verb = Euler.LOGimplies;
			if (e.verb.equals(LOGt))
				e = parse(false, "\"true\"^^xsd:boolean");
			if (e.verb.equals(LOGf))
				e = parse(false, "\"false\"^^xsd:boolean");
			if (e.verb.startsWith(DPO))
				e.verb = Euler.OWL + e.verb.substring(DPO.length());
			if (e.verb.startsWith(ONT))
				e.verb = Euler.OWL + e.verb.substring(ONT.length());
			if (e.verb.equals(OWLequivalentTo))
				e.verb = Euler.OWLsameAs;
			if (e.verb.equals(OWLsameIndividualAs))
				e.verb = Euler.OWLsameAs;
			if (e.verb.equals(OWLsameClassAs))
				e.verb = Euler.OWLequivalentClass;
			if (e.verb.equals(OWLsamePropertyAs))
				e.verb = Euler.OWLequivalentProperty;
			if (e.verb.equals(OWLdifferentIndividualFrom))
				e.verb = Euler.OWLdifferentFrom;
			if (e.verb.equals(OWLUnambiguousProperty))
				e.verb = Euler.OWLInverseFunctionalProperty;
			if (e.verb.equals(OWLUniqueProperty))
				e.verb = Euler.OWLFunctionalProperty;
			if (e.verb.equals(Euler.RDFfirst))
				e.cverb = "rdf:first";
			if (e.verb.equals(Euler.RDFrest))
				e.cverb = "rdf:rest";
			if (e.verb.equals(Euler.RDFnil))
				e.cverb = "()";
			if (e.verb.equals("?"))
				e.verb = e.cverb = "?anon_" + pos;
			if (e.verb.startsWith("?") && vt != null && !vt.contains(e.verb))
				vt.addElement(e.verb);
			if (vt != null)
				e.varid = vt.indexOf(e.verb);
			if (e.varid == -1)
				e.bound = true;
			if (nt.equals(".") && (str.charAt(pos) == ' ' || str.charAt(pos) == '\t' || str.charAt(pos) == '\r' || str.charAt(pos) == '\n' || str.charAt(pos) == '\ufeff'))
				return new Euler();
			if (!nt.equals("rdf:first") && str != null && pos < str.length() && str.charAt(pos) == '^' && str.charAt(pos + 1) == '^') {
				pos = pos + 2;
				Euler et = parse(false, tokenize());
				if (!et.verb.equals(Euler.XSDstring)) {
					e.subj = e.copy();
					e.verb = e.cverb = "^^";
					e.bound = true;
					e.obj = et;
				}
			}
			String ev = (String) Euler.z.get(e.verb);
			if (ev != null)
				e.verb = ev;
			else
				Euler.z.put(e.verb, e.verb);
			if (b) {
				nt = tokenize();
				if (nt.equals("{")) {
					lv++;
					nt = tokenize();
					if (nt.equals("."))
						e.obj = parse(false, "{}");
					else
						e.obj = parse(true, nt);
					Euler el = e.obj;
					while (el.near != null)
						el = el.near;
					nt = tokenize();
					while (nt != null && !nt.equals("}")) {
						el.near = parse(true, nt);
						while (el.near != null)
							el = el.near;
						nt = tokenize();
					}
					lv--;
				} else if (nt.equals("[")) {
					e.obj = parse(true, null);
					if (e.obj.verb != null)
						r.verb = ";]";
					nt = tokenize();
					if (!nt.equals("]"))
						System.err.println("** Parser error ** " + u + " line " + line + ": (p3) expecting ] at " + e + " but got " + nt);
				} else if (nt.equals("("))
					list(e);
				else
					e.obj = parse(false, nt);
				path(e.obj);
				nt = tokenize();
				if (nt == null)
					return e;
				if (nt.endsWith("\"\"\"")) {
					e.obj.cverb = e.obj.cverb + nt;
					e.obj.verb = e.obj.cverb;
					nt = tokenize();
				}
				Euler el = e;
				while (nt.equals(";") || nt.equals(",")) {
					while (el.near != null)
						el = el.near;
					if (nt.equals(";")) {
						nt = tokenize();
						if (nt.equals("]")) {
							r.verb = ";]";
							nt = ";";
							break;
						} else if (nt.equals("."))
							break;
						el.near = parse(false, nt);
					} else if (nt.equals(",")) {
						el.near = parse(false, el.cverb);
						el.near.cverb = el.cverb;
					}
					el.near.subj = e.subj;
					nt = tokenize();
					if (nt.equals("{")) {
						lv++;
						nt = tokenize();
						if (nt.equals("."))
							el.near.obj = parse(false, "{}");
						else
							el.near.obj = parse(true, nt);
						Euler ef = el.near.obj;
						while (ef.near != null)
							ef = ef.near;
						nt = tokenize();
						while (nt != null && !nt.equals("}")) {
							ef.near = parse(true, nt);
							while (ef.near != null)
								ef = ef.near;
							nt = tokenize();
						}
						lv--;
					} else if (nt.equals("[")) {
						el.near.obj = parse(true, null);
						if (el.near.obj.verb != null)
							r.verb = ";]";
						nt = tokenize();
						if (!nt.equals("]"))
							System.err.println("** Parser error ** " + u + " line " + line + ": (p4) expecting ] at " + e + " but got " + nt);
					} else if (nt.equals("("))
						list(el.near);
					else
						el.near.obj = parse(false, nt);
					nt = tokenize();
					if (nt == null)
						return e;
					if (nt.endsWith("\"\"\"")) {
						el.near.obj.cverb = el.near.obj.cverb + nt;
						el.near.obj.verb = el.near.obj.cverb;
						nt = tokenize();
					}
					swap(el.near);
				}
				if (!nt.equals(".") && !nt.equals(";"))
					System.err.println("** Parser error ** " + u + " line " + line + ": (p5) expecting . or ; at " + e + " but got " + nt);
			}
			swap(e);
			if (e.verb.equals(Euler.LOGimplies) && e.subj != null && e.subj.verb.equals("{}")) {
				e.obj.vv = true;
				e = e.obj;
			}
			e.far = r;
			return e;
		} catch (NullPointerException exc) {
			exc.printStackTrace();
			return e;
		}
	}

	String tokenize() {
		String nt = token();
		while (pos < str.length() && nt == null)
			nt = token();
		return nt;
	}

	String next() {
		int start = pos;
		while (pos < str.length() && ST.indexOf(str.charAt(pos)) < 0)
			pos++;
		if (pos < str.length() && start == pos && ST.indexOf(str.charAt(pos)) >= 0)
			pos++;
		if (pos < str.length() && str.charAt(pos) == '\n')
			line++;
		return str.substring(start, pos);
	}

	String token() {
		if (r.verb != null && r.verb.equals(".}"))
			return r.verb = "}";
		if (r.verb != null && r.verb.equals(";]"))
			return r.verb = "]";
		if (pos >= str.length())
			return null;
		int start = pos;
		String t = null;
		String nt = next();
		if (nt.indexOf('#') != -1) {
			t = nt.substring(0, nt.indexOf('#'));
			String v = r.verb;
			while (nt != null && !nt.equals("\n") && pos < str.length())
				nt = next();
			r.verb = v;
			if (t.equals(""))
				return null;
		} else if (nt.equals("SELECT")) {
			StringBuffer sb = new StringBuffer("(");
			nt = tokenize();
			while (!nt.equals("\r") && !nt.equals("\n") && pos < str.length()) {
				sb.append(nt);
				nt = next();
			}
			t = sb.append(')').toString();
		} else if (nt.equals("CONSTRUCT")) {
			t = tokenize();
		} else if (nt.equals("FROM")) {
			// TODO
			nt = tokenize();
			if (nt.equals("NAMED"))
				tokenize();
			t = tokenize();
		} else if (nt.equals("UNION")) {
			t = ".";
		} else if (nt.equals("OPTIONAL")) {
			// TODO
			t = tokenize();
		} else if (nt.equals("FILTER")) {
			// TODO
			t = tokenize();
		} else if (nt.equals("@base")) {
			String b = tokenize();
			u = toURI(b.substring(1, b.length() - 1));
			tokenize();
			return null;
		} else if (nt.equals("@prefix") || nt.equals("PREFIX")) {
			String nsc = tokenize();
			if (nsc.equals("default"))
				nsc = ":";
			String nsd = null;
			String nsu = tokenize();
			if (u != null && nsu.length() > 0 && nsu.charAt(0) == '<' && nsu.indexOf(':') == -1)
				nsu = '<' + toURI(nsu.substring(1, nsu.length() - 1)) + '>';
			for (Enumeration enr = r.ext.ns.keys(); enr.hasMoreElements();) {
				String nsx = (String) enr.nextElement();
				String nsy = (String) r.ext.ns.get(nsx);
				if (nsu.equals(nsy))
					nsd = nsx;
			}
			if (nsd == null) {
				nsd = nsc;
				String nsv = (String) r.ext.ns.get(nsd);
				int i = 0;
				while (nsv != null && !nsu.equals(nsv)) {
					nsd = "p" + i + nsc;
					nsv = (String) r.ext.ns.get(nsd);
					i++;
				}
			}
			r.ext.nsp.put(nsc, nsd);
			r.ext.ns.put(nsd, nsu);
			if (nt.equals("@prefix"))
				tokenize();
			return null;
		} else if (nt.equals("@keywords")) {
			while (nt != null && !nt.equals(".") && pos < str.length()) {
				nt = next();
				if (!nt.equals(" ") && !nt.equals("\t") && !nt.equals("\r") && !nt.equals("\n") && !nt.equals("\ufeff") && !nt.equals(",") && !nt.equals("."))
					r.ext.kw.put(nt, r);
			}
			t = tokenize();
		} else if (nt.equals("@true")) {
			t = "true";
		} else if (nt.equals("@false")) {
			t = "false";
		} else if (nt.equals("\"")) {
			StringBuffer sb = new StringBuffer("\"");
			if (str.charAt(pos) == '"' && str.charAt(pos + 1) == '"') {
				sb.append(next()).append(next());
				while (pos < str.length() && (str.charAt(pos) != '"' || str.charAt(pos + 1) != '"' || str.charAt(pos + 2) != '"'))
					sb.append(next());
				sb.append(next()).append(next()).append(next());
			} else {
				nt = next();
				while (!nt.equals("\"")) {
					if (nt.equals("\\")) {
						sb.append(nt);
						nt = next();
					}
					sb.append(nt);
					if (pos >= str.length()) {
						System.err.println("** Parser error ** " + u + " line " + line + ": (t1) expecting \" at " + sb);
						break;
					}
					nt = next();
				}
				sb.append("\"");
			}
			if (pos < str.length() && str.charAt(pos) == '@') {
				String lang = token();
				int i = lang.indexOf('-');
				if (i != -1)
					sb.append(lang.substring(0, i) + lang.substring(i).toUpperCase());
				else
					sb.append(lang);
			}
			t = sb.toString().replace("\\\\", "\\");
		} else if (nt.equals("'")) {
			StringBuffer sb = new StringBuffer("'");
			nt = next();
			while (!nt.equals("'")) {
				sb.append(nt);
				if (pos >= str.length()) {
					System.err.println("** Parser error ** " + u + " line " + line + ": (t2) expecting ' at " + sb);
					break;
				}
				nt = next();
			}
			t = sb.append("'").toString();
		} else if (nt.equals("<") && str.charAt(pos) == '=') {
			next();
			t = "=>@@";				
		} else if (nt.equals("<")) {
			StringBuffer sb = new StringBuffer("<");
			nt = next();
			while (!nt.equals(">")) {
				sb.append(nt);
				if (pos >= str.length()) {
					System.err.println("** Parser error ** " + u + " line " + line + ": (t2) expecting > at " + sb);
					break;
				}
				nt = next();
			}
			t = sb.append(">").toString();
		} else if (nt.equals("=")) {
			if (str.charAt(pos) == '>')
				t = nt + next();
			else
				t = nt;
		} else if (nt.equals("is") || nt.equals("@is")) {
			t = tokenize();
			nt = tokenize();
			if (!(nt.equals("of") || nt.equals("@of")))
				System.err.println("** Parser error ** " + u + " line " + line + ": (t4) expecting \"of\" but got " + nt);
			t = t + "@@";
		} else if (nt.equals("has") || nt.equals("@has")) {
			t = tokenize() + "_@";
			int cpos = pos;
			nt = tokenize();
			if (!(nt.equals("of") || nt.equals("@of")))
				pos = cpos;
		} else if (nt.equals(" ") || nt.equals("\t") || nt.equals("\r") || nt.equals("\n") || nt.equals("\ufeff") || nt.equals("-") || nt.equals(">"))
			return null;
		else if (nt.startsWith("_:") && !nt.endsWith("_"))
			t = nt + "_" + r.doc + "_";
		else
			t = nt;
		if (pos < str.length() && ST.indexOf(t) == -1 && t.charAt(0) != '"' && str.charAt(pos) == '"')
			t = t + token();
		while (pos < str.length() - 1 && str.charAt(pos) == '.' && str.charAt(pos + 1) != ' ' && str.charAt(pos + 1) != '\t'
				&& str.charAt(pos + 1) != '\r' && str.charAt(pos + 1) != '\n' && str.charAt(pos + 1) != '\ufeff'
				&& str.charAt(pos + 1) != ']' && str.charAt(pos + 1) != '}' && str.charAt(pos + 1) != '#') {
			t = t + next() + next();
		}
		if (r.verb != null && t != null && !r.verb.equals(".") && t.equals("}")) {
			r.verb = ".}";
			return ".";
		}
		if (r.verb != null && t != null && !r.verb.equals(";") && t.equals("]")) {
			r.verb = ";]";
			return ";";
		}
		return r.verb = t;
	}

	void swap(Euler e) {
		if (e != null && e.subj == null && e.cverb.endsWith("@@")) {
			e.subj = e.obj;
			e.obj = parse(false, e.cverb.substring(0, e.cverb.length() - 2));
			e.verb = e.cverb = "!";
		} else if (e.subj != null && e.obj != null && e.cverb.endsWith("@@")) {
			Euler el = e.subj;
			e.subj = e.obj;
			e.obj = el;
			e.cverb = e.cverb.substring(0, e.cverb.length() - 2);
		}
	}

	void list(Euler e) {
		Euler el = e;
		while (true) {
			String nt = tokenize();
			if (nt.startsWith("@")) {
				el.obj = parse(false, nt.substring(1));
				nt = tokenize();
				if (!nt.equals(")"))
					System.err.println("** Parser error ** " + u + " line " + line + ": (p6) expecting ) at " + el + " but got " + nt);
				break;
			} else if (nt.equals(")")) {
				el.obj = parse(false, "rdf:nil");
				break;
			} else
				el.obj = parse(false, "rdf:first");
			if (nt.equals("{")) {
				lv++;
				nt = tokenize();
				if (nt.equals("."))
					el.obj.obj = parse(false, "{}");
				else
					el.obj.obj = parse(true, nt);
				Euler er = el.obj.obj;
				while (er.near != null)
					er = er.near;
				nt = tokenize();
				while (!nt.equals("}")) {
					er.near = parse(true, nt);
					while (er.near != null)
						er = er.near;
					nt = tokenize();
				}
				lv--;
			} else if (nt.equals("[")) {
				//el.obj.obj = parse(true, null);
				Euler f = parse(true, null);
				if (f.verb.equals(Euler.RDFfirst))
					el.obj.obj = f;
				else {
					f.subj = parse(false, "_:e" + f.uid + "_" + r.doc + "_");
					el.obj.obj = f.subj;
					if (lv == 0)
						str = str + f;
				}
				tokenize();
			} else
				el.obj.obj = parse(false, nt);
			path(el.obj.obj);
			el.obj.near = parse(false, "rdf:rest");
			el = el.obj.near;
		}
		path(e.obj);
	}

	void path(Euler e) {
		if (str != null && pos < str.length() - 1 && str.charAt(pos) == '!' && str.charAt(pos + 1) != ' '
				&& str.charAt(pos + 1) != '\t' && str.charAt(pos + 1) != '\r' && str.charAt(pos + 1) != '\n' && str.charAt(pos + 1) != '\ufeff'
				&& str.charAt(pos + 1) != ']' && str.charAt(pos + 1) != '}' && str.charAt(pos + 1) != '#') {
			pos = pos + 1;
			e.subj = e.copy();
			e.verb = e.cverb = "!";
			e.varid = -1;
			e.bound = true;
			e.obj = parse(false, tokenize());
			e.near = null;
			path(e);
		}
		if (str != null && pos < str.length() - 1 && str.charAt(pos) == '^' && str.charAt(pos + 1) != '^'
				&& str.charAt(pos + 1) != ' ' && str.charAt(pos + 1) != '\t' && str.charAt(pos + 1) != '\r'
				&& str.charAt(pos + 1) != '\n' && str.charAt(pos + 1) != '\ufeff'
				&& str.charAt(pos + 1) != ']' && str.charAt(pos + 1) != '}' && str.charAt(pos + 1) != '#') {
			pos = pos + 1;
			e.subj = e.copy();
			e.verb = e.cverb = "^";
			e.varid = -1;
			e.bound = true;
			e.obj = parse(false, tokenize());
			if (e.obj.verb.equals(Euler.Esource) && e.subj.cverb == null)
				e.subj = parse(false, toQName(u + "#line_" + line));
			e.near = null;
			path(e);
		}
	}

	final String toQName(String nsq) {
		int nsh = nsq.lastIndexOf('#');
		int nss = nsq.lastIndexOf('/');
		int nsc = nsq.lastIndexOf(':');
		int nsi = (nsh != -1 ? nsh + 1 : (nss != -1 ? nss + 1 : nsc + 1));
		String nsu = '<' + nsq.substring(0, nsi) + '>';
		String nsn = nsq.substring(nsi);
		String nsp = null;
		for (Enumeration enr = r.ext.ns.keys(); enr.hasMoreElements();) {
			String nsx = (String) enr.nextElement();
			String nsy = (String) r.ext.ns.get(nsx);
			if (nsu.equals(nsy))
				nsp = nsx;
		}
		if (nsp == null) {
			int i = 0;
			while (true) {
				nsp = "nsp" + i + ':';
				if (r.ext.ns.get(nsp) == null)
					break;
				i++;
			}
			r.ext.ns.put(nsp, nsu);
		}
		return nsp + nsn;
	}

	final String toURI(String s) {
		if (s.equals(""))
			return u;
		try {
			if (!u.startsWith("_:"))
				s = new URI(u).resolve(s).toString();
		} catch (Exception e) {
			System.err.println("** Parser error ** " + u + " line " + line + ": found " + s + "\n" + e);
		}
		return s;
	}
}