Handle relations, improve XML rendering (wow, was that hard.

The Java class library can be really sucky!)

diff --git a/README b/README
index 6d123c7..ad98b9c 100644 (file)
--- a/README
+++ b/README
@@ -1,4 +1,4 @@
-$Id: README,v 1.3 2002-10-25 07:38:16 mike Exp $
+$Id: README,v 1.4 2002-10-29 10:15:58 mike Exp $
 
 cql-java -- a free CQL compiler for Java
 
@@ -76,3 +76,29 @@ SEE ALSO
 Adam Dickmeiss's CQL compiler, written in C.
 Rob Sanderson's CQL compiler, written in Python.
 All the other free CQL compilers everyone's going to write.
+
+
+TO DO
+-----
+
+### Finish the parser:
+###    * multi-character relations             DONE but ### single "<" fails!
+###    * word relations
+###    * relation modifiers
+###    * proximity, 
+
+### Finish the CXQL-rendering back end (mostly a matter of quoting
+    characters to be emitted as part of an XML document).
+       DONE
+
+### Finish CQL-decompiling back end (mostly a matter of quoting)
+
+### Write PQN-generating back end (will need to be driven from a
+    configuation file specifying how to represent the qualifiers,
+    relations, relation modifiers and wildcard characters as Z39.50
+    attributes.)
+
+### Write stochastic query generator, driven off MA grammar.
+
+### Write "javadoc" comments.
+

diff --git a/src/org/z3950/zing/cql/CQLNode.java b/src/org/z3950/zing/cql/CQLNode.java
index baa6cad..3d16a37 100644 (file)
--- a/src/org/z3950/zing/cql/CQLNode.java
+++ b/src/org/z3950/zing/cql/CQLNode.java
@@ -1,4 +1,4 @@
-// $Id: CQLNode.java,v 1.5 2002-10-27 00:46:25 mike Exp $
+// $Id: CQLNode.java,v 1.6 2002-10-29 10:15:58 mike Exp $
 
 package org.z3950.zing.cql;
 
@@ -7,7 +7,7 @@ package org.z3950.zing.cql;
  * Represents a node in a CQL parse-tree ...
  * ###
  *
- * @version    $Id: CQLNode.java,v 1.5 2002-10-27 00:46:25 mike Exp $
+ * @version    $Id: CQLNode.java,v 1.6 2002-10-29 10:15:58 mike Exp $
  */
 public abstract class CQLNode {
     abstract String toXCQL(int level);
@@ -21,14 +21,36 @@ public abstract class CQLNode {
        return x;
     }
 
+    // XML Quote --
+    // s/&/&/g;
+    // s/</&lt;/g;
+    // s/>/&gt;/g;
+    // This is hideously inefficient, but I just don't see a better
+    // way using the standard JAVA library.
+    //
     protected String xq(String str) {
-       // XML Quote
-       // ###  s/&/&amp;/g;
-       //      s/</&lt;/g;
-       //      s/>/&gt;/g;
+       str = replace(str, "&", "&amp;");
+       str = replace(str, "<", "&lt;");
+       str = replace(str, ">", "&gt;");
        return str;
     }
 
+    String replace(String str, String from, String to) {
+       StringBuffer sb = new StringBuffer();
+       int ix;                 // index of next `from'
+       int offset = 0;         // index of previous `from' + length(from)
+
+       while ((ix = str.indexOf(from, offset)) != -1) {
+           sb.append(str.substring(offset, ix));
+           sb.append(to);
+           offset = ix + from.length();
+       }
+
+       // End of string: append last bit and we're done
+       sb.append(str.substring(offset));
+       return sb.toString();
+    }
+
     // Test harness
     public static void main (String[] args) {
        CQLNode n1 = new CQLTermNode("dc.author", "=", "kernighan");

diff --git a/src/org/z3950/zing/cql/CQLParser.java b/src/org/z3950/zing/cql/CQLParser.java
index 16d9bd6..8c5d871 100644 (file)
--- a/src/org/z3950/zing/cql/CQLParser.java
+++ b/src/org/z3950/zing/cql/CQLParser.java
@@ -1,4 +1,4 @@
-// $Id: CQLParser.java,v 1.8 2002-10-27 00:46:25 mike Exp $
+// $Id: CQLParser.java,v 1.9 2002-10-29 10:15:58 mike Exp $
 
 package org.z3950.zing.cql;
 import java.util.Properties;
@@ -12,14 +12,14 @@ import java.io.StreamTokenizer;
  * Compiles a CQL string into a parse tree ...
  * ###
  *
- * @version    $Id: CQLParser.java,v 1.8 2002-10-27 00:46:25 mike Exp $
+ * @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 = false;
+    static private boolean LEXDEBUG = true;
 
     private class CQLParseException extends Exception {
        CQLParseException(String s) { super(s); }
@@ -100,6 +100,7 @@ public class CQLParser {
 
            qualifier = word;
            relation = lexer.render(false);
+           debug("got relation '" + relation + "'");
            match(lexer.ttype);
            debug("qualifier='" + qualifier + ", relation='" + relation + "'");
        }
@@ -110,10 +111,13 @@ public class CQLParser {
     }
 
     boolean isRelation() {
-       // ### Also need to handle <=, >=, <>
+       // ### Handle any, all and exact
        return (lexer.ttype == '<' ||
                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)
@@ -191,7 +195,15 @@ public class CQLParser {
 // a render() method.  Used only by CQLParser.
 //
 class CQLLexer extends StreamTokenizer {
-    private static boolean lexdebug;
+    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));
@@ -202,16 +214,39 @@ class CQLLexer extends StreamTokenizer {
        this.ordinaryChar('(');
        this.ordinaryChar(')');
        this.wordChars('\'', '\''); // prevent this from introducing strings
-       this.lexdebug = lexdebug;
+       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);
+
+       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;
     }
@@ -234,9 +269,15 @@ class CQLLexer extends StreamTokenizer {
        } else if (token == this.TT_NUMBER) {
            return "number: " + this.nval;
        } else if (token == this.TT_WORD) {
-           return "word: \"" + this.sval + "\"";
+           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);