-// $Id: CQLParser.java,v 1.7 2002-10-25 16:56:43 mike Exp $
+// $Id: CQLParser.java,v 1.8 2002-10-27 00:46:25 mike Exp $
package org.z3950.zing.cql;
import java.util.Properties;
* Compiles a CQL string into a parse tree ...
* ###
*
- * @version $Id: CQLParser.java,v 1.7 2002-10-25 16:56:43 mike Exp $
+ * @version $Id: CQLParser.java,v 1.8 2002-10-27 00:46:25 mike Exp $
* @see <A href="http://zing.z3950.org/cql/index.html"
* >http://zing.z3950.org/cql/index.html</A>
*/
public class CQLParser {
- private String cql;
- private StreamTokenizer st;
+ private CQLLexer lexer;
+ static private boolean PARSEDEBUG = false;
+ static private boolean LEXDEBUG = false;
private class CQLParseException extends Exception {
CQLParseException(String s) { super(s); }
}
- public CQLParser() {
- // Nothing to do: do we need this constructor, then?
+ static void debug(String str) {
+ if (PARSEDEBUG)
+ System.err.println("PARSEDEBUG: " + str);
}
public CQLNode parse(String cql)
throws CQLParseException, IOException {
- this.cql = cql;
- st = new StreamTokenizer(new StringReader(cql));
- st.ordinaryChar('=');
- st.ordinaryChar('<');
- st.ordinaryChar('>');
- st.ordinaryChar('/');
- st.ordinaryChar('(');
- st.ordinaryChar(')');
-
- if (false) {
- // Lexical debug
- int token;
- while ((token = st.nextToken()) != st.TT_EOF) {
- System.out.println("token=" + token + ", " +
- "nval=" + st.nval + ", " +
- "sval=" + st.sval);
- }
- System.exit(0);
- }
+ lexer = new CQLLexer(cql, LEXDEBUG);
- st.nextToken();
- System.err.println("*about to parse_query()");
- CQLNode root = parse_query();
- if (st.ttype != st.TT_EOF)
- throw new CQLParseException("junk after end: " + render(st));
+ 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()
+ private CQLNode parse_query(String qualifier, String relation)
throws CQLParseException, IOException {
- System.err.println("*in parse_query()");
-
- CQLNode term = parse_term();
- while (st.ttype == st.TT_WORD) {
- String op = st.sval.toLowerCase();
- System.err.println("*checking op '" + op + "'");
- if (st.sval.equals("and")) {
- match(st.TT_WORD);
- CQLNode term2 = parse_term();
+ 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 (st.sval.equals("or")) {
- match(st.TT_WORD);
- CQLNode term2 = parse_term();
+ } else if (lexer.sval.equals("or")) {
+ match(lexer.TT_WORD);
+ CQLNode term2 = parse_term(qualifier, relation);
term = new CQLOrNode(term, term2);
- } else if (st.sval.equals("not")) {
- match(st.TT_WORD);
- CQLNode term2 = parse_term();
+ } 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 + "'");
}
- // ### Need to handle "prox"
}
- System.err.println("*no more ops");
+ debug("no more ops");
return term;
}
- private CQLNode parse_term()
+ private CQLNode parse_term(String qualifier, String relation)
throws CQLParseException, IOException {
- System.err.println("*in parse_term()");
- if (st.ttype == '(') {
- match('(');
- CQLNode expr = parse_query();
- match(')');
- return expr;
+ 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);
+ match(lexer.ttype);
+ debug("qualifier='" + qualifier + ", relation='" + relation + "'");
}
- System.err.println("*not a parenthesised term");
- // ### Need to parse qualifier-relation pairs
- String word = st.sval;
- match(st.ttype);
- CQLTermNode node = new CQLTermNode("x", "=", word);
- System.err.println("*made term node " + node);
+ CQLTermNode node = new CQLTermNode(qualifier, relation, word);
+ debug("made term node " + node);
return node;
}
- private void match(int token)
- throws CQLParseException, IOException {
- System.err.println("*in match(" + render(st, token, null) + ")");
- if (st.ttype != token)
- throw new CQLParseException("expected " + render(st, token, null) +
- ", " + "got " + render(st));
- st.nextToken();
- }
-
- // ### This utility should surely be a method of the StreamTokenizer class
- private static String render(StreamTokenizer st) {
- return render(st, st.ttype, null);
+ boolean isRelation() {
+ // ### Also need to handle <=, >=, <>
+ return (lexer.ttype == '<' ||
+ lexer.ttype == '>' ||
+ lexer.ttype == '=');
}
- private static String render(StreamTokenizer st, int token, String str) {
- String ret;
-
- if (token == st.TT_EOF) {
- return "EOF";
- } else if (token == st.TT_EOL) {
- return "EOL";
- } else if (token == st.TT_NUMBER) {
- return "number: " + st.nval;
- } else if (token == st.TT_WORD) {
- return "word: \"" + st.sval + "\"";
- } else if (token == '"' || token == '\'') {
- return "string: \"" + st.sval + "\"";
- }
-
- return "'" + String.valueOf((char) token) + "'";
+ 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();
}
// 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) {
// 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);
+ System.err.println("Can't read query: " + ex.getMessage());
System.exit(2);
}
String cql = new String(bytes);
CQLNode root;
try {
root = parser.parse(cql);
- System.err.println("root='" + root + "'");
+ debug("root='" + root + "'");
System.out.println(root.toXCQL(0));
} catch (CQLParseException ex) {
- System.err.println("Syntax error: " + ex);
+ System.err.println("Syntax error: " + ex.getMessage());
System.exit(3);
} catch (java.io.IOException ex) {
- System.err.println("Can't compile query: " + 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;
+
+ 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 (lexdebug)
+ System.out.println("LEXDEBUG: " +
+ "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 + "\"";
+ }
+
+ String res = String.valueOf((char) token);
+ if (quoteChars) res = "'" + res + "'";
+ return res;
+ }
+}
projects / cql-java-moved-to-github.git / commitdiff