-$Id: README,v 1.7 2002-10-31 22:22:01 mike Exp $
-cql-java -- a free CQL compiler for Java
+CQL-Java - a free CQL compiler, and other CQL tools, for Java
-This project provides a set of classes for representing a CQL parse
-tree (CQLBooleanNode, CQLTermNode, etc.) and a CQLCompiler class which
-builds a parse tree given a CQL query as input. It also provides
-compiler back-ends to render out the parse tree as XCQL (the XML
-representation), as PQF (Yaz-style Prefix Query Format) and as CQL
-(i.e. decompiling the parse-tree). Oh, and there's a random query
-generator, too.
+INTRODUCTION
+------------
-CQL is "Common Query Language", a new query language designed under
+CQL-Java is a Free Software project that provides:
+
+* A set of classes for representing a CQL parse tree (a base CQLNode
+ class, CQLBooleanNode and its subclasses, CQLTermNode, etc.)
+* A CQLCompiler class (and its lexer) which builds a parse tree given
+ a CQL query as input.
+* A selection of compiler back-ends to render out the parse tree as:
+ * XCQL (the standard XML representation)
+ * CQL (i.e. decompiling the parse-tree)
+ * PQF (Yaz-style Prefix Query Format)
+ * BER code for the Z39.50 Type-1 query
+* A random query generator, useful for testing.
+
+CQL is "Common Query Language", a query language designed under
the umbrella of the ZING initiative (Z39.59-International Next
-Generation). More information at
+Generation). The official specification is at
+ http://www.loc.gov/standards/sru/cql/
+and there's more (and friendlier) information at
http://zing.z3950.org/cql/index.html
XCQL is "XML CQL", a representation of CQL-equivalent queries in XML
-which is supposed to be easier to parse. More information at
- http://www.loc.gov/z3950/agency/zing/srwu/xcql.html
-(not much more, though)
+which is supposed to be easier to parse. The specification is at
+ http://www.loc.gov/standards/sru/xml-files/xcql.xsd
+in the form of an XML Schema.
But if you didn't know that, why are you even reading this? :-)
+WHAT'S WHAT IN THIS DISTRIBUTION?
+---------------------------------
+
+ README This file
+ Changes History of releases
+ LGPL-2.1 The GNU lesser GPL (see below)
+ pom.xml Maven project file to control compilation.
+ src Source-code for the CQL-Java library and tests
+ target The compiled library file, "cql-java.jar" and javadoc
+ bin Simple shell-scripts to invoke CQL programs (parser/lexer/generator)
+ util Various testing and sanity-checking Perl scripts
+ etc Other files: PQF indexes, generator properties, etc.
+
+
+COMPILATION AND INSTALLATION
+----------------------------
+
+The build process is controlled by Maven so compilation is the standard:
+
+ mvn clean install
+
+which generates build artifacts under target/.
+
+"Installation" of this package would consist of putting the bin
+directory on your PATH and target/cql-java.jar on your CLASSPATH.
+
+
SYNOPSIS
--------
-Test-harness:
+Using the test-harnesses:
- $ echo "foo and (bar or baz)" | java org.z3950.zing.cql.CQLParser
+ $ CQLParser 'title=foo and author=(bar or baz)'
+ $ CQLParser -c 'title=foo and author=(bar or baz)'
+ $ CQLParser -p /etc/pqf.properties 'dc.title=foo and dc.author=bar'
+ $ CQLLexer 'title=foo and author=(bar or baz)'
+ (not very interesting unless you're debugging)
+ $ CQLGenerator etc/generate.properties seed 18
-Library:
+Using the library in your own applications:
import org.z3950.zing.cql.*
// Building a parse-tree by hand
- CQLNode n1 = new CQLTermNode("dc.author", "=", "kernighan");
- CQLNode n2 = new CQLTermNode("dc.title", "all", "elements style");
+ CQLNode n1 = new CQLTermNode("dc.author", new CQLRelation("="),
+ "kernighan");
+ CQLNode n2 = new CQLTermNode("dc.title", new CQLRelation("all"),
+ "elements style");
CQLNode root = new CQLAndNode(n1, n2);
- System.out.println(root.toXCQL(3));
+ System.out.println(root.toXCQL(0));
// Parsing a CQL query
CQLParser parser = new CQLParser();
CQLNode root = parser.parse("title=dinosaur");
- System.out.println(root.toXCQL(0));
+ System.out.print(root.toXCQL(0));
System.out.println(root.toCQL());
- System.out.println(root.toPQF(qualSet));
- // ... where `qualSet' specifies CQL-qualfier => Z-attr mapping
+ System.out.println(root.toPQF(config));
+ // ... where `config' specifies CQL-qualfier => Z-attr mapping
DESCRIPTION
-----------
-See the automatically generated class documentation in the "doc"
-subdirectory. (It's not all there yet, but it's coming.)
+See the automatically generated class documentation in the "target"
+subdirectory.
AUTHOR
------
-Mike Taylor <mike@z3950.org>
-http://www.miketaylor.org.uk
+Original code and documentation by Mike Taylor, Index Data <mike@indexdata.com>
+At present maintained by Jakub Skoczen, Index Data <jakub@indexdata.dk>
+
+ http://www.indexdata.com/cql-java
+ http://zing.z3950.org/cql
+
+Please email me with bug-reports, wishlist items, patches, deployment
+stories and, of course, large cash donations.
LICENCE
-------
-This software is open source, but I've not yet decided exactly what
-licence to use. Be good. Assume I'm going with the GPL (most
-restrictive) until I say otherwise.
+The CQL-Java suite is Free Software, which is pretty much legally
+equivalent -- though not morally equivalent -- to Open Source. See
+ http://www.gnu.org/philosophy/free-software-for-freedom.html
+for a detailed if somewhat one-sided discussion of the differences,
+and particularly of why Free Software is an important idea.
+
+CQL-Java is distributed under version 2.1 of the LGPL (GNU LESSER
+GENERAL PUBLIC LICENSE). A copy of the licence is included in this
+distribution, as the file LGPL-2.1. This licence does not allow you
+to restrict the freedom of others to use derived versions of CQL-Java
+(i.e. you must share your enhancements), but does let you do pretty
+much anything else with it. In particular, you may deploy CQL-Java as
+a part of a non-free larger work.
SEE ALSO
Adam Dickmeiss's CQL compiler, written in C.
Rob Sanderson's CQL compiler, written in Python.
+Jakub Skoczen's CQL-js compiler, written in JavaScript http://git.indexdata.com/?p=cql-js.git
All the other free CQL compilers everyone's going to write :-)
-
-
-TO DO
------
-
-* Add proximity support to parser -- just the back-ends left to do.
-
-* Relation modifiers could be limited to known modifiers only.
-
-* Fix CQLParser and CQLLexer shell-script front-ends to elegantly
- handle their classes' test harnesses' ability to read the query from
- the command-line arguments, if any, falling back to stdin if there
- are none.
-
-* Add CQLGenerate shell-script. Allow CQLGenerate test-harness to
- take some arguments on command-line as well as or instead of a
- file.
-
-* Trivial CQLCanonicalise application, which renders out its source
- tree in a canonical form, enabling queries to be diffed for
- semantically significant differences only. Tests can be run by
- generating random trees, canonicalising them, then canonicalising
- them _again_ and checking that the before-and-after results are the
- same.
-
-* Some niceties for the cql-decompiling back-end:
- * don't emit redundant parentheses.
- * don't put spaces around relations that don't need them.
-
-* 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.)
-
-* Consider the utility of yet another back-end that translates a
- cqlnode tree into a type-1 query tree using the jzkit data
- structures. That would be nice so that CQL could become a JZKit
- query-type, but you could achieve the same effect by generating PQN,
- and running that through JZKit's existing PQN-to-Type-1 compiler.
-
-* Refinements to random query generator:
- * Generate relation modifiers
- * Proximity support
- * Don't always generate qualifier/relation for terms
- * Better selection of qualifier (configurable?)
- * Better selection of terms (from a dictionary file?)
- * Introduce wildcard characters into generated terms
- * Generate multi-word terms
-
-* Write fuller "javadoc" comments.
-
-* Write generic test suite.
-
+The "Changes" file, including the "Still to do" section.
projects / cql-java-moved-to-github.git / blobdiff