--- a/lex/index.html Wed May 18 11:50:59 2016 +0100
+++ b/lex/index.html Wed May 18 13:45:30 2016 +0100
@@ -33,7 +33,7 @@
in order to deal with POSIX matching, which is the underlying
disambiguation strategy for regular expressions needed in lexers.
Sulzmann and Lu have made available on-line what they call a
-''rigorous proof'' of the correctness of their algorithm w.r.t. their
+``rigorous proof'' of the correctness of their algorithm w.r.t. their
specification; regrettably, it appears to us to have unfillable gaps.
In the first part of this paper we give our inductive definition of
what a POSIX value is and show (i) that such a value is unique (for
@@ -44,27 +44,27 @@
algorithm. Our definitions and proof are much simpler than those by
Sulzmann and Lu and can be easily formalised in Isabelle/HOL. In the
second part we analyse the correctness argument by Sulzmann and Lu and
-explain why it seems hard to turn it into a proof rigorous enough to
-be accepted by a system such as Isabelle/HOL.
+explain why the gaps in this argument cannot be filled easily.
+
<H3>Theory Files for Isabelle 2016</H3>
<ul>
-<li> <A HREF="http://talisker.inf.kcl.ac.uk/%7Eurbanc/cgi-bin/repos.cgi/lexing/raw-file/tip/thys/ReStar.thy">ReStar.thy</A>
+<li> <A HREF="http://talisker.inf.kcl.ac.uk/%7Eurbanc/cgi-bin/repos.cgi/lexing/raw-file/tip/thys/Lexer.thy">ReStar.thy</A>
<li> <A HREF="http://talisker.inf.kcl.ac.uk/%7Eurbanc/cgi-bin/repos.cgi/lexing/raw-file/tip/thys/Simplifying.thy">Simplifying.thy</A>
-<li> <A HREF="http://talisker.inf.kcl.ac.uk/%7Eurbanc/cgi-bin/repos.cgi/lexing/raw-file/tip/thys/Sulzmann.thy">Sulzmann.thy</A>
</ul>
<H3>Links</H3>
<ul>
+<li> <A HREF="http://talisker.inf.kcl.ac.uk/%7Eurbanc/cgi-bin/repos.cgi/lexing/raw-file/tip/thy/paper.pdf">our paper</A>
<li> <A HREF="http://talisker.inf.kcl.ac.uk/%7Eurbanc/cgi-bin/repos.cgi/lexing/raw-file/tip/Literature/sulzmann14-new.pdf">the paper</A> by Sulzmann and Lu
</ul>
</TABLE>
<P>
-<!-- hhmts start --> Last modified: Tue Mar 15 12:48:13 GMT 2016 <!-- hhmts end -->
+<!-- hhmts start --> Last modified: Wed May 18 13:44:30 BST 2016 <!-- hhmts end -->
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--- a/lex/index.html~ Wed May 18 11:50:59 2016 +0100
+++ /dev/null Thu Jan 01 00:00:00 1970 +0000
@@ -1,70 +0,0 @@
-<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN"
-"http://www.w3.org/TR/REC-html40/loose.dtd">
-<HEAD>
-<TITLE>HGMP</TITLE>
-<BASE HREF="http://www.inf.kcl.ac.uk/staff/urbanc/">
-</HEAD>
-
-<BODY TEXT="#000000"
- BGCOLOR="#4169E1"
- LINK="#0000EF"
- VLINK="#51188E"
- ALINK="#FF0000">
-
-<TABLE WIDTH="100%"
- BGCOLOR="#4169E1"
- BORDER="0"
- FRAME="border"
- CELLPADDING="10"
- CELLSPACING="2"
- RULES="all">
-
-<!-- right column -->
-<TR>
-<TD BGCOLOR="#FFFFFF" WIDTH="75%">
-<H2>POSIX Lexing with Derivatives of Regular Expressions (Proof Pearl)</H2>
-
-Fahad Ausaf, Roy Dyckhoff, Christian Urban
-<p>
-
-Brzozowski introduced the notion of derivatives for regular
-expressions. They can be used for a very simple regular expression
-matching algorithm. Sulzmann and Lu cleverly extended this algorithm
-in order to deal with POSIX matching, which is the underlying
-disambiguation strategy for regular expressions needed in lexers.
-Sulzmann and Lu have made available on-line what they call a
-''rigorous proof'' of the correctness of their algorithm w.r.t. their
-specification; regrettably, it appears to us to have unfillable gaps.
-In the first part of this paper we give our inductive definition of
-what a POSIX value is and show (i) that such a value is unique (for
-given regular expression and string being matched) and (ii) that
-Sulzmann and Lu's algorithm always generates such a value (provided
-that the regular expression matches the string). We also prove the
-correctness of an optimised version of the POSIX matching
-algorithm. Our definitions and proof are much simpler than those by
-Sulzmann and Lu and can be easily formalised in Isabelle/HOL. In the
-second part we analyse the correctness argument by Sulzmann and Lu and
-explain why it seems hard to turn it into a proof rigorous enough to
-be accepted by a system such as Isabelle/HOL.
-
-<H3>Theory Files for Isabelle 2016</H3>
-
-<ul>
-<li> <A HREF="http://talisker.inf.kcl.ac.uk/%7Eurbanc/cgi-bin/repos.cgi/lexing/raw-file/tip/thys/ReStar.thy">ReStar.thy</A>
-<li> <A HREF="http://talisker.inf.kcl.ac.uk/%7Eurbanc/cgi-bin/repos.cgi/lexing/raw-file/tip/thys/Simplifying.thy">Simplifying.thy</A>
-<li> <A HREF="http://talisker.inf.kcl.ac.uk/%7Eurbanc/cgi-bin/repos.cgi/lexing/raw-file/tip/thys/Sulzmann.thy">Sulzmann.thy</A>
-</ul>
-
-
-<H3>Links</H3>
-
-<ul>
-<li> <A HREF="http://talisker.inf.kcl.ac.uk/%7Eurbanc/cgi-bin/repos.cgi/lexing/raw-file/tip/Literature/sulzmann14-new.pdf">the paper</A> by Sulzmann and Lu
-</ul>
-
-</TABLE>
-<P>
-<!-- hhmts start --> Last modified: Tue Mar 15 12:47:17 GMT 2016 <!-- hhmts end -->
-<a href="http://validator.w3.org/check/referer">[Validate this page.]</a>
-</BODY>
-</HTML>