Norman Ramsey

Send email to nr@cs.tufts.edu.
Send physical documents to my postal address.
If you come yourself you'll want directions.
Telephone +1 617 627 4923.
Skype (chat preferred): norman-ramsey
AIM: norman62ramsey
Yahoo chat: norman_ramsey
Fax +1 617 627 2227 (but if you can, scan and email instead)
My vita and public key (now with photo!) are online.

I type 75 words per minute. We are typists first, so test yourself.

On this page:

Book

Textbook

For some time now I have been teaching from a draft textbook which is intended to introduce the field of programming languages to an audience composed primarily of people who will have careers in software. My working title is Programming Languages: Build, Prove, and Compare, and if you want you can read a little bit about it.

Research

My research interests are broad, but grounded in programming languages. I like programming languages because there is nothing like a good language to help us express computations precisely, in ways that we can reason about them, while still keeping things at a high level.

I focus on reusable, low-level programming-language infrastructure; I want to make it easy and cheap to build the programming languages of the future. I also work in functional programming and programming-language design, including the design of special-purpose languages for solving problems in distributed systems.

My most recent work has been on reusable back ends and optimization libraries, which has been applied to the increasingly misnamed Glasgow Haskell Compiler (GHC). My research is currently in transition: I am working on or interested in compilers; interpreters; precise, machine-checkable, composable specifications for programming assignments; algorithms and infrastructure for managing replicated data; and distributed version control.

Selected papers

I have collected both highly significant and recent papers. Links are to abstracts so you can check out the topic without downloading a monster. For a complete view, including older work, see my publications list.

Five most significant papers

Relocating Machine Instructions by Currying. Proceedings of the ACM SIGPLAN '96 Conference on Programming Language Design and Implementation, in SIGPLAN Notices, 31(5):226–236, May 1996.
This paper connects two worlds: the ``low cult'' of systems programming and the pure, mathematical world of the lambda-calculus. The key insight is that relocation, which is a low-level operation performed on binary code, is an instance of currying, which is the expression of a multiple-argument function in the lambda-calculus.
Stochastic Lambda Calculus and Monads of Probability Distributions (with Avi Pfeffer). Proceedings of the 29th ACM Symposium on the Principles of Programming Languages, in SIGPLAN Notices, 37(1):154–165, January 2002.
This paper explores the design of probabilistic languages in a foundational, principled way. Its special contribution is to analyze important implementation techniques in a way that is completely formal and is rigorously connected to the theory of probability.
A Transformational Approach to Binary Translation of Delayed Branches (with Cristina Cifuentes). ACM Transactions on Programming Languages and Systems, 25(2):210–224, March 2003.
The paper solves a small but difficult problem in analysis of binary codes. This problem is repeatedly a stumbling block for industry groups that work with binary codes, and I believe our solution is definitive.
An Expressive Language of Signatures (with Kathleen Fisher and Paul Govereau). In Proceedings of the Tenth ACM SIGPLAN International Conference on Functional Programming (ICFP'05), pages 27–40, September 2005.
In this paper, we identified an important class of programming problems the solutions to which cannot be expressed in current languages, and we showed that these problems can be solved by new mechanisms that cohere with an existing language.
Automatically Generating Back Ends Using Declarative Machine Descriptions (with João Dias). In Proceedings of the 37th ACM Symposium on the Principles of Programming Languages, pages 403–416, January 2010.
The most beautiful results from João Dias's doctoral dissertation: (a) if all you know is the semantics of the intermediate code and the target instruction set, generating a code generator is undecidable; and (b) by using a clever new heuristic search based on algebraic laws, João can generate code generators for real machines quickly. The core of the algorithm combines Hoare logic and unification to find sequences of machine instructions that implement intermediate code. Will appeal especially to those who like inference rules with their compilers.

Five other significant papers

Specifying Representations of Machine Instructions (with Mary F. Fernández). ACM Transactions on Programming Languages and Systems, 19(3):492–524, May 1997.
This is the most technical and the definitive description of my early work on declarative machine descriptions.
A Single Intermediate Language That Supports Multiple Implementations of Exceptions (with Simon L. Peyton Jones). Proceedings of the ACM SIGPLAN '00 Conference on Programming Language Design and Implementation, in SIGPLAN Notices, 35(5):285–298, May 2000.
This paper is the most technical and rigorous of the C-- papers. It exemplifies what I am trying to achieve in C--: clean, low-level mechanisms that compiler writers can use to implement different high-level–language features and to control cost tradeoffs.
An Algebraic Approach to File Synchronization (with Elöd Csirmaz). In Proceedings of the 8th European Software Engineering Conference (ESEC) and 9th ACM SIGSOFT Symposium on the Foundations of Software Engineering (FSE-9), pages 175–185, September 2001.
This paper discusses how to maintain consistency among multiple replicas of files that may be modified concurrently. We proposed reasoning about this problem by examining the algebraic structure of a sequence of modifications.
A Generalized Algorithm for Graph-Coloring Register Allocation (with Michael D. Smith and Glenn Holloway). ACM SIGPLAN '04 Conference on Programming Language Design and Implementation, in SIGPLAN Notices, 39(6):277–288, June 2004.
A new technique for dealing with irregularities in target machines, which arise because not all machine registers can be used interchangeably. We hope this will be the definitive paper on handling irregular register files in a graph-coloring register allocator.
Staged Allocation: A Compositional Technique for Specifying and Implementing Procedure Calling Conventions (with Reuben Olinsky and Christian Lindig). In Proceedings of the 33rd ACM Symposium on the Principles of Programming Languages, pages 409–421, January 2006.
A specification language for parameter passing, unique in having a formal semantics. Together with an earlier paper on stack-frame layout, a complete approach to calling conventions.

Other recent papers

These are some recent papers not listed above. They are in chronological order, so the most recent work is at the bottom.

Hoopl: A Modular, Reusable Library for Dataflow Analysis and Transformation (with João Dias and Simon Peyton Jones). In Proceedings of the 3rd ACM SIGPLAN Symposium on Haskell (Haskell 2010), September 2010.
We implement dataflow analysis and transformation in modular fashion using advanced features of Haskell. Unlike our 2009 technical report, which emphasizes the advantages of using Hoopl, this paper focuses on the implementation, which has been carefully modularized to separate each of the tricky bits from all of the others. Of greatest interest to hard-core functional programmers and compiler writers.
Resourceable, Retargetable, Modular Instruction Selection Using a Machine-Independent, Type-Based Tiling of Low-Level Intermediate Code (with João Dias). In Proceedings of the 38th ACM Symposium on the Principles of Programming Languages, pages 575–586, January 2011.
In most compilers, building an instruction selector requires a mapping from intermediate form to target-machine instructions. The mapping must be defined once per target machine. Here we describe a single mapping that works for all register machines. By using this mapping, we make the machine-dependent components simple enough that they can be generated automatically.
Teaching Technical Writing Using the Engineering Method. A handbook for teaching writing to students in science or engineering. Accompanied by a student's edition.
Embedding an Interpreted Language Using Higher-Order Functions and Types. Journal of Functional Programming, 21(6):585–615, November 2011. (A previous version appeared in ACM SIGPLAN 2003 Workshop on Interpreters, Virtual Machines and Emulators.).
Homage to Olivier Danvy: How to embed an application-specific function into an interpreter simply by describing its type. The paper, while not technically deep, shows the capabilities of functional languages to elegant advantage, and it is representative of my work on interpreters.
Experience Report: Haskell in Computational Biology (with Noah M. Daniels and Andrew Gallant). In Proceedings of the Seventeenth ACM SIGPLAN International Conference on Functional Programming (ICFP'12), September 2012. To appear.
Encouragement for computational biologists to try Haskell. If you are a functional programmer, you will see an interesting variation on lazy search. You might also get some insight into why beginners may find it difficult to use QuickCheck.

For a complete view, including older work, see my publications list.

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The documents contained in these pages are included to ensure timely dissemination of scholarly and technical work on a non-commercial basis. Copyright and all rights therein are maintained by the authors or by other copyright holders, notwithstanding that they have offered their works here electronically. It is understood that all persons copying this information will adhere to the terms and constraints invoked by each author's copyright. These works may not be reposted without the explicit permission of the copyright holder.

Teaching

In Fall 2012 I am teaching a seminar applying functional-programming ideas to the study of distributed source-code control (git and all that).

In Spring 2013 I am teaching COMP 105 (Programming Languages).

In 2013–2014, Ben Hescott and I will be co-teaching new versions of our introductory courses, COMP 11 and COMP 15.

In the past, I have taught COMP 40 (Machine Structures and Assembly-Language Programming), COMP 105 (Programming Languages), COMP 150DAO (Dataflow Analysis and Optimization), COMP 150FP (Advanced Functional Programming), and COMP 150TW (The Engineering Method of Technical Writing), as well as many courses at other universities that need not be named.

Resources for Students

Office hours for Fall 2012 are Mondays from 3:45–4:30, Thursdays from 2:00–3:00, and by appointment.

If you are interested in the development of the new versions of COMP 11 and COMP 15, I am holding additional office hours most Fridays from 2:00–4:00. These additional hours are for curriculum development only.

I am always interested in discussing projects with students, and I often have several undergraduate or master's students working with me part-time.

I have gathered material of interest to research students, including resources for writers, and how to give a talk.
Undergraduate research students might also be interested, especially in my thoughts about admission to graduate programs. And I tell you what you need to give me (and when) if you want a letter of recommendation.

About Me

My professional home is in the Department of Computer Science at Tufts University. Some people think I'm a power user; others think I never sleep. My ORCID ID is 0000-0002-5435-1135.

I currently serve ACM as a member of the SIGPLAN Executive Committee. I served as program chair for ICFP '07.

I no longer maintain a hot list; this is more of a random list. An interest in personal productivity and pointers from Benjamin Pierce and Phil Wadler got me to Inbox Zero on Wed 21 Feb 2007 at 6:00 PM. After serious lossage caused by various alarums and excursions, I recovered Zero at 6:30 PM on Mon 31 Dec 2007. It was a pleasure to start the New Year with an empty inbox! After starting at Tufts, I got a little behind; at the end of my first year, my email debt was over 600 messages. At the end of my third year, at 9:12 PM on Monday 23 May 2011, I recovered Zero once again, but I cheated—I put 600 messages from 2009 and 2010 into an email demilitarized zone. The next time I got to Zero wasat 5:03 PM on Wednesday 29 August 2012. I signed the email charter; if you won't, I won't.

I'm a Bellcore alumnus and a long-standing member of the Luxuriant Flowing Hair Club for Scientists, and I have an Erdös Number of 3. I've been seen wearing orange and black academic regalia. Despite these distinguished credentials, I'm not ashamed to subscribe to a magazine with a centerfold. A secret vice is that I used to answer programming questions for fun; at one time, I was the 40th most reputable contributor (out of over 100,000). Along the way I earned silver Specialist badges in C, Haskell, programming languages, functional programming, and a couple of other topics.

Although it surprises some people, for over thirty years I have been a foot ball fan. When it's not football season, I've been known to play Guild Wars. I also have a rare autographed copy of Ad Verbum. I try to avoid P. J. Brown's deadly sins. I'm married to a licensed psychologist and game designer. I've appeared onstage (and in various clubs) as a jazz pianist, as a dancer, but most often as a chorister. My wish-fulfillment dreams are of sleeping.