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>CDuce is fast, functional,
type-safe, and <b>conforms to basic standards</b>: <a href="http://www.unicode.org">Unicode</a>, <a href="http://www.w3.org/XML/">XML</a>, <a href="http://www.w3.org/TR/REC-xml#dt-doctype">DTD</a>,
<a href="http://www.w3.org/TR/REC-xml-names/">Namespaces</a> are fully supported, partial support of <a href="http://www.w3.org/TR/xmlschema-1/">XML Schema</a> validation is
in alpha testing (and undocumented) while queries are being
implemented.
</p>

<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
27	<left>
28
29	<p> CDuce ("seduce") is a new typed functional language with
30	innovative features.</p>
31
32	<p> Although CDuce is a general programming language, it features
33	several characteristics that make it adapted to XML documents
34	manipulation (transformation, extraction of information, creation of
35	documents).
36	<a href="http://www.w3.org/XML/">XML</a> is a syntax to
37	describe tree-like documents (aka semi-structured data), and XML
38	documents often come with a description of their type. The type is
39	expressed in a system like DTD, or
40	<a href="http://www.w3.org/XML/Schema">XML Schema</a>.
41	XML types play a central role in CDuce.
42	</p>
43
44	</left>
45
46	<left>
47	<p> All pages of this site were automatically generated from an XML description of
48	the content by <a href="examples.html#site">the following CDuce program</a>.
49	</p><p>
50	<img src="img/cducepower2.jpg" alt="Powered by CDuce"/></p>
51	</left>
52
53
54	<box title="What is CDuce ?" link="whatis">
55
56	<p> <b>CDuce</b> is modern programming language, adapted to the
57	manipulation of XML documents. It is developped by the <a
58	href="http://www.di.ens.fr/~castagna/EQUIPE"><b>Languages</b></a>
59	group of ENS in Paris and the <a
60	href="http://www.lri.fr/bd"><b>Databases</b></a> group of LRI in
61	Orsay, two <a href="http://www.cnrs.fr">CNRS</a> labs.
62	See also the <local href="team">CDuce team</local> page,
63	our <local href="papers">technical papers</local>.
64	</p>
65
66	<section title="Online running prototype">
67	<p> To get a feeling of CDuce,
68	you can play with the <local href="proto">online prototype</local>,
69	try the examples and modify them. We also have some
70	<local href="examples">larger examples</local>. </p>
71
72	<p>We are planning to distribute a stable release in the next
73	few weeks. To help us prepare this release, you can download a
74	<local href="download">beta version</local>, and send your comments.
75	</p>
76
77	</section>
78	</box>
79
80	<box title="Design and features" link="design">
81	<p> Our point of view and our guideline for the design of CDuce is
82	that a programming language for XML should take XML types (
83	DTD, XML Schema, Relax-NG, ...) seriously. The benefit are the following:</p>
84
85	<ul>
86	<li> <b>static verifications</b>
87	(e.g.: ensure that a transformation produces a valid document);</li>
88	<li> in particular, we aim at <b>smooth and safe</b> compositions
89	of XML transformations, and incremental programming;</li>
90	<li> static <b>optimizations</b> and <b>efficient execution model</b>
91	(knowing the type of a document is crucial to extract information
92	efficiently).</li>
93	</ul>
94
95	<p>
96	Some of CDuce peculiar features:
97	</p>
98	<ul>
99	<li> XML objects can be manipulated as first-class citizen values:
100	elements, sequences, tags, characters and strings, attribute
101	sets; sequences of XML elements can be specified by
102	<b>regular expressions</b>, which also apply to
103	characters strings; </li>
104	<li> functions themselves are <b>first-class</b> values, they
105	can be manipulated, stored in data structure, returned by
106	a function,...</li>
107	<li> a powerful <b>pattern matching</b> operation can perform
108	complex extractions from sequences of XML elements; </li>
109	<li> a rich <b>type algebra</b>, with recursive types and arbitrary
110	boolean combinations (union, intersection, complement) allows
111	precise definitions of data structures and XML types;
112	<b>general purpose types</b> and types constructors are taken seriously
113	(products, extensible records, arbitrary precision integers with interval
114	constraints, Unicode characters);</li>
115	<li> <b>polymorphism</b> through a natural notion of <b>subtyping</b>,
116	and <b>overloaded functions</b> with dynamic dispatch; </li>
117	<li> an highly-effective <b>type-driven compilation schema</b>. </li>
118	</ul>
119
120	<p>CDuce is fast, functional,
121	type-safe, and <b>conforms to basic standards</b>: <a href="http://www.unicode.org">Unicode</a>, <a href="http://www.w3.org/XML/">XML</a>, <a href="http://www.w3.org/TR/REC-xml#dt-doctype">DTD</a>,
122	<a href="http://www.w3.org/TR/REC-xml-names/">Namespaces</a> are fully supported, partial support of <a href="http://www.w3.org/TR/xmlschema-1/">XML Schema</a> validation is
123	in alpha testing (and undocumented) while queries are being
124	implemented.
125	</p>
126
127	<p>
128	<local href="bench">Preliminary benchmarks</local> suggest that despite the
129	overhead for static type verification, a CDuce
130	program can run faster (30% to 60%) than an equivalent XSLT
131	style-sheet (we performed benchmarks with
132	the xsltproc tools from the Gnome libxslt library).
133	</p>
134	</box>
135
136	<box title="Research directions" link="research">
137
138	<p>Our plans concerning the design of the core language
139	include:</p>
140	<ul>
141	<li>a module system to support incremental programming;</li>
142	<li>parametric polymorphism;</li>
143	<li>XML-friendly primitives, to mimic XSLT transformations.</li>
144	</ul>
145
146	<p>
147	Apart from the core language design and implementation,
148	our research projects include:
149	</p>
150	<ul>
151	<li> integration of a <b>query sub-language</b> into CDuce, using
152	types as a primary optimization strategy for request evaluation;</li>
153	<li> study of <b>security</b> (confidentiality, ...) properties in the
154	setting of XML transformations.</li>
155	</ul>
156
157	<p>
158	We wrote several <local href="papers">technical papers</local> about
159	the language design and its theoretical foundations.
160	</p>
161	</box>
162
163	<box title="XDuce and CDuce" link="xduce">
164	<p>
165
166	The starting point of our work on CDuce was the
167	<a href="http://xduce.sourceforge.net/">XDuce</a> language developped
168	at the UPenn DB group. Many of CDuce features originate from XDuce.
169	Some of our achievements:
170
171	</p>
172	<ul>
173	<li>integration of first-class and overloaded functions, arbitrary boolean
174	connectives, and extensible (or not) records, to the semantic
175	definition of subtyping;</li>
176	<li>a subtyping algorithm without backtracking;</li>
177	<li>extending pattern matching to capture non consecutive
178	subsequences; removing tail condition for exact matching
179	(they arrived independently to another solution);</li>
180	<li>efficient evaluation model that takes profit of static type information;</li>
181	</ul>
182	<p>
183	Of course, the work on XDuce continued during our, and they
184	developped nice ideas: mixed attribute-element types (same
185	expressive power as our records, but they can sometimes avoid exponential
186	explosion where we cannot); powerful filter operation.
187	</p>
188	</box>
189
190	<box title="Related links" link="links">
191	<ul>
192	<li> <link url="http://www.w3.org/XML/"
193	title="Extensible Markup Language (XML)"> The W3C page on XML. </link>
194	</li>
195	<li> <link url="http://www.research.avayalabs.com/user/wadler/xml/"
196	title="XML: Some hyperlinks minus the hype"> By Philip Wadler. </link>
197	</li>
198	<li> <link url="http://xduce.sourceforge.net/"
199	title="XDuce"> XDuce home page. </link> </li>
200	</ul> </box>
201
202
203	<meta>
204	<p>
205	<a href="comeon.htm">
206	<img style="border:0;width:88px;height:31px"
207	src="img/cducepower3.png"
208	alt="Powered by CDuce"/>
209	</a>
210
211	<a href="http://validator.w3.org/check?uri=http%3A%2F%2Fwww.cduce.org">
212	<img style="border:0;width:88px;height:31px"
213	src="http://www.w3.org/Icons/valid-xhtml10"
214	alt="Valid XHTML 1.0!"/>
215	</a>
216
217	<a href="http://jigsaw.w3.org/css-validator/">
218	<img style="border:0;width:88px;height:31px"
219	src="http://jigsaw.w3.org/css-validator/images/vcss"
220	alt="Valid CSS!"/>
221	</a>
222
223	<a href="http://www.ens.fr">
224	<img style="border:0"
225	src="img//symbENSmio.gif"
226	alt="ENS" title="ENS"/>
227	</a>
228
229	<a href="http://www.u-psud.fr">
230	<img style="border:0"
231	src="img//symbP11mio.gif"
232	alt="Paris 11" title="Paris 11"/>
233	</a>
234
235	<a href="http://www.cnrs.fr">
236	<img style="border:0"
237	src="img//symbCNRSmio.gif"
238	alt="CNRS" title="CNRS"/>
239	</a>
240	</p>
241	<p>
242	<a href="mailto:Alain.Frisch@ens.fr">Webmaster</a> -
243	<local href="sitemap">Site map</local>
244	</p>
245	</meta>
246
247	</page>