-// ### not _quite_ finished yet ...
+// $Id: CQLParser.java,v 1.9 2002-10-29 10:15:58 mike Exp $
+
+package org.z3950.zing.cql;
+import java.util.Properties;
+import java.io.InputStream;
+import java.io.IOException;
+import java.io.StringReader;
+import java.io.StreamTokenizer;
+
+
+/**
+ * Compiles a CQL string into a parse tree ...
+ * ###
+ *
+ * @version $Id: CQLParser.java,v 1.9 2002-10-29 10:15:58 mike Exp $
+ * @see <A href="http://zing.z3950.org/cql/index.html"
+ * >http://zing.z3950.org/cql/index.html</A>
+ */
+public class CQLParser {
+ private CQLLexer lexer;
+ static private boolean PARSEDEBUG = false;
+ static private boolean LEXDEBUG = true;
+
+ private class CQLParseException extends Exception {
+ CQLParseException(String s) { super(s); }
+ }
+
+ static void debug(String str) {
+ if (PARSEDEBUG)
+ System.err.println("PARSEDEBUG: " + str);
+ }
+
+ public CQLNode parse(String cql)
+ throws CQLParseException, IOException {
+ lexer = new CQLLexer(cql, LEXDEBUG);
+
+ lexer.nextToken();
+ debug("about to parse_query()");
+ CQLNode root = parse_query("srw.serverChoice", "=");
+ if (lexer.ttype != lexer.TT_EOF)
+ throw new CQLParseException("junk after end: " + lexer.render());
+
+ return root;
+ }
+
+ private CQLNode parse_query(String qualifier, String relation)
+ throws CQLParseException, IOException {
+ debug("in parse_query()");
+
+ CQLNode term = parse_term(qualifier, relation);
+ while (lexer.ttype == lexer.TT_WORD) {
+ String op = lexer.sval.toLowerCase();
+ debug("checking op '" + op + "'");
+ if (lexer.sval.equals("and")) {
+ match(lexer.TT_WORD);
+ CQLNode term2 = parse_term(qualifier, relation);
+ term = new CQLAndNode(term, term2);
+ } else if (lexer.sval.equals("or")) {
+ match(lexer.TT_WORD);
+ CQLNode term2 = parse_term(qualifier, relation);
+ term = new CQLOrNode(term, term2);
+ } else if (lexer.sval.equals("not")) {
+ match(lexer.TT_WORD);
+ CQLNode term2 = parse_term(qualifier, relation);
+ term = new CQLNotNode(term, term2);
+ } else if (lexer.sval.equals("prox")) {
+ // ### Handle "prox"
+ } else {
+ throw new CQLParseException("unrecognised boolean: '" +
+ lexer.sval + "'");
+ }
+ }
+
+ debug("no more ops");
+ return term;
+ }
+
+ private CQLNode parse_term(String qualifier, String relation)
+ throws CQLParseException, IOException {
+ debug("in parse_term()");
+
+ String word;
+ while (true) {
+ if (lexer.ttype == '(') {
+ debug("parenthesised term");
+ match('(');
+ CQLNode expr = parse_query(qualifier, relation);
+ match(')');
+ return expr;
+ } else if (lexer.ttype != lexer.TT_WORD && lexer.ttype != '"') {
+ throw new CQLParseException("expected qualifier or term, " +
+ "got " + lexer.render());
+ }
+
+ debug("non-parenthesised term");
+ word = lexer.sval;
+ match(lexer.ttype);
+ if (!isRelation())
+ break;
+
+ qualifier = word;
+ relation = lexer.render(false);
+ debug("got relation '" + relation + "'");
+ match(lexer.ttype);
+ debug("qualifier='" + qualifier + ", relation='" + relation + "'");
+ }
+
+ CQLTermNode node = new CQLTermNode(qualifier, relation, word);
+ debug("made term node " + node);
+ return node;
+ }
+
+ boolean isRelation() {
+ // ### Handle any, all and exact
+ return (lexer.ttype == '<' ||
+ lexer.ttype == '>' ||
+ lexer.ttype == '=' ||
+ lexer.ttype == lexer.TT_LE ||
+ lexer.ttype == lexer.TT_GE ||
+ lexer.ttype == lexer.TT_NE);
+ }
+
+ private void match(int token)
+ throws CQLParseException, IOException {
+ debug("in match(" + lexer.render(token, null, true) + ")");
+ if (lexer.ttype != token)
+ throw new CQLParseException("expected " +
+ lexer.render(token, null, true) +
+ ", " + "got " + lexer.render());
+ lexer.nextToken();
+ }
+
+
+ // Test harness.
+ //
+ // e.g. echo '(au=Kerninghan or au=Ritchie) and ti=Unix' |
+ // java org.z3950.zing.cql.CQLParser
+ // yields:
+ // <triple>
+ // <boolean>and</boolean>
+ // <triple>
+ // <boolean>or</boolean>
+ // <searchClause>
+ // <index>au<index>
+ // <relation>=<relation>
+ // <term>Kerninghan<term>
+ // </searchClause>
+ // <searchClause>
+ // <index>au<index>
+ // <relation>=<relation>
+ // <term>Ritchie<term>
+ // </searchClause>
+ // </triple>
+ // <searchClause>
+ // <index>ti<index>
+ // <relation>=<relation>
+ // <term>Unix<term>
+ // </searchClause>
+ // </triple>
+ //
+ public static void main (String[] args) {
+ if (args.length != 0) {
+ System.err.println("Usage: " + args[0]);
+ System.exit(1);
+ }
+
+ byte[] bytes = new byte[10000];
+ try {
+ // Read in the whole of standard input in one go
+ int nbytes = System.in.read(bytes);
+ } catch (java.io.IOException ex) {
+ System.err.println("Can't read query: " + ex.getMessage());
+ System.exit(2);
+ }
+ String cql = new String(bytes);
+ CQLParser parser = new CQLParser();
+ CQLNode root;
+ try {
+ root = parser.parse(cql);
+ debug("root='" + root + "'");
+ System.out.println(root.toXCQL(0));
+ } catch (CQLParseException ex) {
+ System.err.println("Syntax error: " + ex.getMessage());
+ System.exit(3);
+ } catch (java.io.IOException ex) {
+ System.err.println("Can't compile query: " + ex.getMessage());
+ System.exit(4);
+ }
+ }
+}
+
+
+// This is a trivial subclass for java.io.StreamTokenizer which knows
+// about the multi-character tokens "<=", ">=" and "<>", and included
+// a render() method. Used only by CQLParser.
+//
+class CQLLexer extends StreamTokenizer {
+ private static boolean LEXDEBUG;
+ static int TT_LE = 1000; // The token "<="
+ static int TT_GE = 1001; // The token ">="
+ static int TT_NE = 1002; // The token "<>"
+
+ static void debug(String str) {
+ if (LEXDEBUG)
+ System.err.println("LEXDEBUG: " + str);
+ }
+
+ CQLLexer(String cql, boolean lexdebug) {
+ super(new StringReader(cql));
+ this.ordinaryChar('=');
+ this.ordinaryChar('<');
+ this.ordinaryChar('>');
+ this.ordinaryChar('/');
+ this.ordinaryChar('(');
+ this.ordinaryChar(')');
+ this.wordChars('\'', '\''); // prevent this from introducing strings
+ this.LEXDEBUG = lexdebug;
+ }
+
+ public int nextToken() throws java.io.IOException {
+ int token = super.nextToken();
+
+ if (token == '<') {
+ debug("token starts with '<' ...");
+ int t2 = super.nextToken();
+ if (t2 == '=') {
+ debug("token continues with '=' - it's '<='");
+ this.ttype = token = TT_LE;
+ } else if (t2 == '>') {
+ debug("token continues with '>' - it's '<>'");
+ this.ttype = token = TT_NE;
+ } else {
+ debug("next token is " + token + " (pushed back)");
+ //this.pushBack();
+ }
+ } else if (token == '>') {
+ debug("token starts with '>' ...");
+ int t2 = super.nextToken();
+ if (t2 == '=') {
+ debug("token continues with '=' - it's '>='");
+ this.ttype = token = TT_GE;
+ } else {
+ debug("next token is " + token + " (pushed back)");
+ //this.pushBack();
+ }
+ }
+
+ debug("token=" + token + ", " +
+ "nval=" + this.nval + ", " + "sval=" + this.sval);
+
+ return token;
+ }
+
+ String render() {
+ return this.render(this.ttype, null, true);
+ }
+
+ String render(boolean quoteChars) {
+ return this.render(this.ttype, null, quoteChars);
+ }
+
+ String render(int token, String str, boolean quoteChars) {
+ String ret;
+
+ if (token == this.TT_EOF) {
+ return "EOF";
+ } else if (token == this.TT_EOL) {
+ return "EOL";
+ } else if (token == this.TT_NUMBER) {
+ return "number: " + this.nval;
+ } else if (token == this.TT_WORD) {
+ return "word: " + this.sval;
+ } else if (token == '"') {
+ return "string: \"" + this.sval + "\"";
+ } else if (token == TT_LE) {
+ return "<=";
+ } else if (token == TT_GE) {
+ return ">=";
+ } else if (token == TT_NE) {
+ return "<>";
+ }
+
+ String res = String.valueOf((char) token);
+ if (quoteChars) res = "'" + res + "'";
+ return res;
+ }
+}
projects / cql-java-moved-to-github.git / blobdiff