Boston Lispers June 25, 2008

Where: Room 135

DivaScheme http://www.cs.brown.edu/research/plt/software/divascheme/
is a semi-structured text editor layer on top of the DrScheme IDE. It
provides structured editing operations that provide additional support
for the navigation and maintenance of Scheme source code. DivaScheme's
operations act on whole s-expressions rather than characters:
unbalanced parentheses are impossible within the confines of
DivaScheme. It also manages whitespace cleanup and indentation for the
user. Finally, its keybindings are single keystrokes rather than
chords to reduce hand strain.

Danny Yoo http://hkn.eecs.berkeley.edu/~dyoo/ received his bachelor's
from UC Berkeley in 2001, and worked for the Arabidopsis Information
Resource (http://arabidopsis.org) at the Carnegie Institution of
Washington from 2001-2006. He is currently a CS graduate student at
Worcester Polytechnic Institute. His web site is:
http://hashcollision.org/.

Shriram Krishnamurthi will give a 50' talk about
Relationally-Parametric Polymorphic Contracts
http://www.cs.brown.edu/~sk/Publications/Papers/Published/gmfk-rel-par-poly-cont/

The analogy between types and contracts raises the question of how
many features of static type systems can be expressed as dynamic
contracts. An important feature missing in prior work on contracts is
parametricity, as represented by the polymorphic types in languages
like Standard ML.

We present a contract counterpart to parametricity. We explore
multiple designs for such a system and present one that is simple and
incurs minimal execution overhead. We show how to extend the notion of
contract blame to our definition. We present a form of inference that
can often save programmers from having to explicitly instantiate many
parametric contracts. Finally, we present several examples that
illustrate how this system mimics the feel and properties of
parametric polymorphism in typed languages.

Shriram Krishnamurthi http://www.cs.brown.edu/~sk/ is an Associate
Professor of Computer Science at Brown University. His recent work
focuses on language support for interactive software, and on analyses
for security policies. He is a co-author of the DrScheme programming
environment, the FASTLINK genetic linkage analysis package, the
Continue conference paper server, the Margrave access control policy
analysis package, the Flapjax programming language, and the book "How
to Design Programs". He has also written "Programming Languages:
Application and Interpretation" and coordinates the decade-old
TeachScheme! high-school computer science outreach program.

Please note that the meeting is taking places both at an unusual day
(as has been usual) and at an unusual place (as is unusual).

Official Website: http://common-lisp.net/project/boston-lisp/