viewcvs.cgi/web/index.xml

<?xml version="1.0" encoding="ISO-8859-1" standalone="yes"?>
<page name="index">

<title>Home page</title>
<banner>
  <img title="CDuce" src="img/cduce_logo.jpg" width="400" height="206"
       alt="CDuce"/>
</banner>

<left>
<p>On this page:</p>
<boxes-toc/>
<p>Under this page:</p>
<pages-toc/>
</left>

<external href="/cgi-bin/cduce" title="Online demo" name="proto"/>
<include file="download.xml"/>
<include file="bench.xml"/>
<include file="papers.xml"/>
<include file="examples.xml"/>
<include file="team.xml"/>
<include file="manual.xml"/>
<include file="sitemap.xml"/>

<left>

<p> CDuce ("seduce") is a new typed functional language with
innovative features.</p>

<p> Although CDuce is a general programming language, it features
several characteristics that make it adapted to XML documents
manipulation (transformation, extraction of information, creation of
documents).  
<a href="http://www.w3.org/XML/">XML</a> is a syntax to
describe tree-like documents (aka semi-structured data), and XML
documents often come with a description of their type. The type is
expressed in a system like DTD, or 
<a href="http://www.w3.org/XML/Schema">XML Schema</a>.
XML types play a central role in CDuce.
  </p>

</left>

<left>
<p> All pages of this site were automatically generated from an XML description of
the content by <a href="examples.html#site">the following CDuce program</a>.
</p><p> 
<img src="img/cducepower2.jpg" alt="Powered by CDuce"/></p>
</left>


<box title="What is CDuce ?" link="whatis">

<p> <b>CDuce</b> is modern programming language, adapted to the
manipulation of XML documents.  It is developped by the <a
href="http://www.di.ens.fr/~castagna/EQUIPE"><b>Languages</b></a>
group of ENS in Paris and the <a
href="http://www.lri.fr/bd"><b>Databases</b></a> group of LRI in
Orsay, two <a href="http://www.cnrs.fr">CNRS</a> labs.
See also the <local href="team">CDuce team</local> page,
our <local href="papers">technical papers</local>.
</p>

<section title="Online running prototype">
<p> To get a feeling of CDuce,
you can play with the <local href="proto">online prototype</local>,
try the examples and modify them. We also have some 
<local href="examples">larger examples</local>. </p>

<p>We are planning to distribute a stable release in the next
few weeks. To help us prepare this release, you can download a
<local href="download">beta version</local>, and send your comments.
</p>

</section>
</box>

<box title="Design and features" link="design">
<p> Our point of view and our guideline for the design of CDuce is
that a programming language for XML should take XML types (
DTD, XML Schema, Relax-NG, ...) seriously. The benefit are the following:</p>

<ul>
<li> <b>static verifications</b>
(e.g.: ensure that a transformation produces a valid document);</li>
<li> in particular, we aim at <b>smooth and safe</b> compositions
of XML transformations, and incremental programming;</li>
<li> static <b>optimizations</b> and <b>efficient execution model</b>
(knowing the type of a document is crucial to extract information 
efficiently).</li> 
</ul>

<p>
Some of CDuce peculiar features:
</p>
<ul>
<li> XML objects can be manipulated as first-class citizen values:
     elements, sequences, tags, characters and strings, attribute
     sets; sequences of XML elements can be specified by 
     <b>regular expressions</b>, which also apply to
     characters strings; </li>
<li> functions themselves are <b>first-class</b> values, they
     can be manipulated, stored in data structure, returned by
     a function,...</li>
<li> a powerful <b>pattern matching</b> operation can perform
     complex extractions from sequences of XML elements; </li>
<li> a rich <b>type algebra</b>, with recursive types and arbitrary
     boolean combinations (union, intersection, complement) allows
     precise definitions of data structures and XML types;
     <b>general purpose types</b> and types constructors are taken seriously
     (products, extensible records, arbitrary precision integers with interval
     constraints,  Unicode characters);</li>
<li> <b>polymorphism</b> through a natural notion of <b>subtyping</b>,
     and <b>overloaded functions</b> with dynamic dispatch; </li>
<li> an highly-effective <b>type-driven compilation schema</b>. </li>
</ul>

<p>
<local href="bench">Preliminary benchmarks</local> suggest that despite the
overhead for static type verification, a CDuce
program can run faster (30% to 60%) than an equivalent XSLT
style-sheet (we performed benchmarks with
the xsltproc tools from the Gnome libxslt library).
</p>
</box>

<box title="Research directions" link="research">

<p>Our plans concerning the design of the core language
include:</p>
<ul>
 <li>a module system to support incremental programming;</li>
 <li>parametric polymorphism;</li>
 <li>XML-friendly primitives, to mimic XSLT transformations.</li>
</ul>

<p>
Apart from the core language design and implementation, 
our research projects include:
</p>
<ul>
<li> integration of a <b>query sub-language</b> into CDuce, using
     types as a primary optimization strategy for request evaluation;</li>
<li> study of <b>security</b> (confidentiality, ...) properties in the
     setting of XML transformations.</li>
</ul>

<p>
We wrote several <local href="papers">technical papers</local> about
the language design and its theoretical foundations.
</p>
</box>

<box title="XDuce and CDuce" link="xduce">
<p>

The starting point of our work on CDuce was the
<a href="http://xduce.sourceforge.net/">XDuce</a> language developped
at the UPenn DB group. Many of CDuce features originate from XDuce.
Some of our achievements:

</p>
<ul>
<li>integration of first-class and overloaded functions, arbitrary boolean
    connectives, and extensible (or not) records, to the semantic
    definition of subtyping;</li>
<li>a subtyping algorithm without backtracking;</li>
<li>extending pattern matching to capture non consecutive
    subsequences; removing tail condition for exact matching
    (they arrived independently to another solution);</li>
<li>efficient evaluation model that takes profit of static type information;</li>
</ul>
<p>
Of course, the work on XDuce continued during our, and they
developped nice ideas: mixed attribute-element types (same
expressive power as our records, but they can sometimes avoid exponential
explosion where we cannot); powerful filter operation.
</p>
</box>

<box title="Related links" link="links">
<ul>
<li> <link url="http://www.w3.org/XML/"
title="Extensible Markup Language (XML)"> The W3C page on XML. </link>
</li>
<li> <link url="http://www.research.avayalabs.com/user/wadler/xml/"
title="XML: Some hyperlinks minus the hype"> By Philip Wadler. </link>
</li>
<li> <link url="http://xduce.sourceforge.net/"
title="XDuce"> XDuce home page. </link> </li>
</ul> </box>


<meta>
<p>
<a href="comeon.htm">
<img style="border:0;width:88px;height:31px"
     src="img/cducepower3.png" 
     alt="Powered by CDuce"/>
</a>

<a href="http://validator.w3.org/check?uri=http%3A%2F%2Fwww.cduce.org">
<img style="border:0;width:88px;height:31px"
     src="http://www.w3.org/Icons/valid-xhtml10"
     alt="Valid XHTML 1.0!"/>
</a>

<a href="http://jigsaw.w3.org/css-validator/">
<img style="border:0;width:88px;height:31px"
     src="http://jigsaw.w3.org/css-validator/images/vcss" 
     alt="Valid CSS!"/>
</a>

<a href="http://www.ens.fr">
<img style="border:0"
     src="img//symbENSmio.gif"
     alt="ENS" title="ENS"/>
</a>

<a href="http://www.u-psud.fr">
<img style="border:0" 
     src="img//symbP11mio.gif" 
     alt="Paris 11" title="Paris 11"/>
</a>

<a href="http://www.cnrs.fr">
<img style="border:0" 
     src="img//symbCNRSmio.gif" 
     alt="CNRS" title="CNRS"/>
</a>
</p>
<p>
<a href="mailto:Alain.Frisch@ens.fr">Webmaster</a> -
<local href="sitemap">Site map</local>
</p>
</meta>

</page>
1	<?xml version="1.0" encoding="ISO-8859-1" standalone="yes"?>
2	<page name="index">
3
4	<title>Home page</title>
5	<banner>
6	<img title="CDuce" src="img/cduce_logo.jpg" width="400" height="206"
7	alt="CDuce"/>
8	</banner>
9
10	<left>
11	<p>On this page:</p>
12	<boxes-toc/>
13	<p>Under this page:</p>
14	<pages-toc/>
15	</left>
16
17	<external href="/cgi-bin/cduce" title="Online demo" name="proto"/>
18	<include file="download.xml"/>
19	<include file="bench.xml"/>
20	<include file="papers.xml"/>
21	<include file="examples.xml"/>
22	<include file="team.xml"/>
23	<include file="manual.xml"/>
24	<include file="sitemap.xml"/>
25
26	<left>
27
28	<p> CDuce ("seduce") is a new typed functional language with
29	innovative features.</p>
30
31	<p> Although CDuce is a general programming language, it features
32	several characteristics that make it adapted to XML documents
33	manipulation (transformation, extraction of information, creation of
34	documents).
35	<a href="http://www.w3.org/XML/">XML</a> is a syntax to
36	describe tree-like documents (aka semi-structured data), and XML
37	documents often come with a description of their type. The type is
38	expressed in a system like DTD, or
39	<a href="http://www.w3.org/XML/Schema">XML Schema</a>.
40	XML types play a central role in CDuce.
41	</p>
42
43	</left>
44
45	<left>
46	<p> All pages of this site were automatically generated from an XML description of
47	the content by <a href="examples.html#site">the following CDuce program</a>.
48	</p><p>
49	<img src="img/cducepower2.jpg" alt="Powered by CDuce"/></p>
50	</left>
51
52
53	<box title="What is CDuce ?" link="whatis">
54
55	<p> <b>CDuce</b> is modern programming language, adapted to the
56	manipulation of XML documents. It is developped by the <a
57	href="http://www.di.ens.fr/~castagna/EQUIPE"><b>Languages</b></a>
58	group of ENS in Paris and the <a
59	href="http://www.lri.fr/bd"><b>Databases</b></a> group of LRI in
60	Orsay, two <a href="http://www.cnrs.fr">CNRS</a> labs.
61	See also the <local href="team">CDuce team</local> page,
62	our <local href="papers">technical papers</local>.
63	</p>
64
65	<section title="Online running prototype">
66	<p> To get a feeling of CDuce,
67	you can play with the <local href="proto">online prototype</local>,
68	try the examples and modify them. We also have some
69	<local href="examples">larger examples</local>. </p>
70
71	<p>We are planning to distribute a stable release in the next
72	few weeks. To help us prepare this release, you can download a
73	<local href="download">beta version</local>, and send your comments.
74	</p>
75
76	</section>
77	</box>
78
79	<box title="Design and features" link="design">
80	<p> Our point of view and our guideline for the design of CDuce is
81	that a programming language for XML should take XML types (
82	DTD, XML Schema, Relax-NG, ...) seriously. The benefit are the following:</p>
83
84	<ul>
85	<li> <b>static verifications</b>
86	(e.g.: ensure that a transformation produces a valid document);</li>
87	<li> in particular, we aim at <b>smooth and safe</b> compositions
88	of XML transformations, and incremental programming;</li>
89	<li> static <b>optimizations</b> and <b>efficient execution model</b>
90	(knowing the type of a document is crucial to extract information
91	efficiently).</li>
92	</ul>
93
94	<p>
95	Some of CDuce peculiar features:
96	</p>
97	<ul>
98	<li> XML objects can be manipulated as first-class citizen values:
99	elements, sequences, tags, characters and strings, attribute
100	sets; sequences of XML elements can be specified by
101	<b>regular expressions</b>, which also apply to
102	characters strings; </li>
103	<li> functions themselves are <b>first-class</b> values, they
104	can be manipulated, stored in data structure, returned by
105	a function,...</li>
106	<li> a powerful <b>pattern matching</b> operation can perform
107	complex extractions from sequences of XML elements; </li>
108	<li> a rich <b>type algebra</b>, with recursive types and arbitrary
109	boolean combinations (union, intersection, complement) allows
110	precise definitions of data structures and XML types;
111	<b>general purpose types</b> and types constructors are taken seriously
112	(products, extensible records, arbitrary precision integers with interval
113	constraints, Unicode characters);</li>
114	<li> <b>polymorphism</b> through a natural notion of <b>subtyping</b>,
115	and <b>overloaded functions</b> with dynamic dispatch; </li>
116	<li> an highly-effective <b>type-driven compilation schema</b>. </li>
117	</ul>
118
119	<p>
120	<local href="bench">Preliminary benchmarks</local> suggest that despite the
121	overhead for static type verification, a CDuce
122	program can run faster (30% to 60%) than an equivalent XSLT
123	style-sheet (we performed benchmarks with
124	the xsltproc tools from the Gnome libxslt library).
125	</p>
126	</box>
127
128	<box title="Research directions" link="research">
129
130	<p>Our plans concerning the design of the core language
131	include:</p>
132	<ul>
133	<li>a module system to support incremental programming;</li>
134	<li>parametric polymorphism;</li>
135	<li>XML-friendly primitives, to mimic XSLT transformations.</li>
136	</ul>
137
138	<p>
139	Apart from the core language design and implementation,
140	our research projects include:
141	</p>
142	<ul>
143	<li> integration of a <b>query sub-language</b> into CDuce, using
144	types as a primary optimization strategy for request evaluation;</li>
145	<li> study of <b>security</b> (confidentiality, ...) properties in the
146	setting of XML transformations.</li>
147	</ul>
148
149	<p>
150	We wrote several <local href="papers">technical papers</local> about
151	the language design and its theoretical foundations.
152	</p>
153	</box>
154
155	<box title="XDuce and CDuce" link="xduce">
156	<p>
157
158	The starting point of our work on CDuce was the
159	<a href="http://xduce.sourceforge.net/">XDuce</a> language developped
160	at the UPenn DB group. Many of CDuce features originate from XDuce.
161	Some of our achievements:
162
163	</p>
164	<ul>
165	<li>integration of first-class and overloaded functions, arbitrary boolean
166	connectives, and extensible (or not) records, to the semantic
167	definition of subtyping;</li>
168	<li>a subtyping algorithm without backtracking;</li>
169	<li>extending pattern matching to capture non consecutive
170	subsequences; removing tail condition for exact matching
171	(they arrived independently to another solution);</li>
172	<li>efficient evaluation model that takes profit of static type information;</li>
173	</ul>
174	<p>
175	Of course, the work on XDuce continued during our, and they
176	developped nice ideas: mixed attribute-element types (same
177	expressive power as our records, but they can sometimes avoid exponential
178	explosion where we cannot); powerful filter operation.
179	</p>
180	</box>
181
182	<box title="Related links" link="links">
183	<ul>
184	<li> <link url="http://www.w3.org/XML/"
185	title="Extensible Markup Language (XML)"> The W3C page on XML. </link>
186	</li>
187	<li> <link url="http://www.research.avayalabs.com/user/wadler/xml/"
188	title="XML: Some hyperlinks minus the hype"> By Philip Wadler. </link>
189	</li>
190	<li> <link url="http://xduce.sourceforge.net/"
191	title="XDuce"> XDuce home page. </link> </li>
192	</ul> </box>
193
194
195	<meta>
196	<p>
197	<a href="comeon.htm">
198	<img style="border:0;width:88px;height:31px"
199	src="img/cducepower3.png"
200	alt="Powered by CDuce"/>
201	</a>
202
203	<a href="http://validator.w3.org/check?uri=http%3A%2F%2Fwww.cduce.org">
204	<img style="border:0;width:88px;height:31px"
205	src="http://www.w3.org/Icons/valid-xhtml10"
206	alt="Valid XHTML 1.0!"/>
207	</a>
208
209	<a href="http://jigsaw.w3.org/css-validator/">
210	<img style="border:0;width:88px;height:31px"
211	src="http://jigsaw.w3.org/css-validator/images/vcss"
212	alt="Valid CSS!"/>
213	</a>
214
215	<a href="http://www.ens.fr">
216	<img style="border:0"
217	src="img//symbENSmio.gif"
218	alt="ENS" title="ENS"/>
219	</a>
220
221	<a href="http://www.u-psud.fr">
222	<img style="border:0"
223	src="img//symbP11mio.gif"
224	alt="Paris 11" title="Paris 11"/>
225	</a>
226
227	<a href="http://www.cnrs.fr">
228	<img style="border:0"
229	src="img//symbCNRSmio.gif"
230	alt="CNRS" title="CNRS"/>
231	</a>
232	</p>
233	<p>
234	<a href="mailto:Alain.Frisch@ens.fr">Webmaster</a> -
235	<local href="sitemap">Site map</local>
236	</p>
237	</meta>
238
239	</page>