School of Computing

Olaf Chitil

Lecturer / Admissions Officer

Photo of O Chitil, if available
  • Tel:     +44 (0)1227 824320
  • Fax:     +44 (0)1227 762811
  • Email:
  • Room S129
    School of Computing
    University of Kent,
    CT2 7NF


My publications are available from the University of Kent's Academic Repository.

Many of my publications are also on DBLP and Google Scholar.

I also keep a list of external talks, mostly with slides.

Research Interests

I belong to the following research groups:

All my research interests are connected to programming and programming languages. I am interested in semantics and theoretical foundations of programming languages, type theory, program transformation, compiler construction, message-passing-based concurrency, programming tools, and how to write programs. I aim to support programmers in developing software more effectively. My favourite programming languages are functional languages, especially Haskell.



Professional Activities

General chair and local organiser together with Andy King of PPDP 2014 and LOPSTR 2014.

Programme committee chair of IFL 2007.

Programme committee member of , PEPM 2016, LOPSTR 2015, TFP 2015, SLE 2013, ICFP 2013, Haskell Symposium 2013, IFL 2011, DSL 2011, WFLP 2011, TFP 2011, IFL 2010, PADL 2010, IFL 2008, TFP 2006, WCFLP 2005, WFLP 2004, Haskell Workshop 2003, WFLP 2003, IFL 2002, IFL 2001.

I am a member of the PPDP steering commitee. I am also a member of the IFL advisory committee. A long time ago I co-maintained the Haskell Home Page.

I gave the invited talk at PROLE 2013.

Research Students

Do you want to do a PhD? Are you interested in functional programming languages or related topics? Then I would be pleased to hear from you. I have a list of some research topic suggestions.


  • Hat
    is a source-level tracer for Haskell. Often, programmers find it difficult to understand how the different parts of a program cause the computation to perform the observed input/output actions. Hat enables a user to see and interactively explore the usually invisible computation. Thus Hat assists with debugging, understanding complex programs (which we may not have written ourselves) and is useful for teaching.
  • A library for practical typed lazy contracts for Haskell
  • MonadicPromptLazyAssertions
    is a Haskell library for writing assertions that are both prompt and lazy. Properties are formulated in a monadic, parser-combinator-like language. See the APLAS 2007 paper for further information.
  • StrictCheck
    is a tool that tests whether a given Haskell function is least-strict. If it is not, StrictCheck suggests how the function could be less strict. See my IFL 2006 paper, slides and later technical report for further information. StrictCheck requires the Chasing Bottoms library and the Glasgow Haskell compiler.
  • COOSy
    is a library plus viewing tool for lightweight debugging of functional logic programs in Curry by observations. The programmer annotates expressions of interest in their program. With the viewing tool the programmer then views the values the annotated expressions have in a computation.
  • TypeIlluminator
    is a prototype tool implementing the ideas presented in the paper Compositional Explanation of Types and Algorithmic Debugging of Type Errors. It constructs the type explanation graph for programs written in a simple Haskell-like language and enables free navigation through the graph in various ways and algorithmic debugging.
  • FPretty
    is a Haskell library for pretty printing. The library has the same interface as that of Wadler. It is very efficient, in contrast to Wadler's library and the one by John Hughes and Simon Peyton Jones the pretty printer only takes time linear in the size of the printed document; it does not do any backtracking. This version is based on the latest papers by Doaitse Swierstra and me but provides additional combinators following PPrint by Daan Leijen.


I am Director of Undergraduate Admissions of the School of Computing. I also organise the school's demonstrations at university open days and organise the seminars of the Programming Languages and Systems group.


  • CO510 - Software Engineering
  • CO519 - Theory of Computing
  • CO520 - Further Object-Oriented Programming
  • CO884 - Logic and Logic Programming
And therefore education at the University mostly worked by the age-old method of putting a lot of young people in the vicinity of a lot of books and hoping that something would pass from one to the other, while the actual young people put themselves in the vicinity of inns and taverns for exactly the same reason.
    Terry Pratchett, Interesting Times
`Students?' barked the Archchancellor.
`Yes, Master. You know? They're the thinner ones with the pale faces? Because we're a university? They come with the whole thing, like rats -'.

    Terry Pratchett, Moving Pictures
`What sort of people would we be if we didn't go into the Library?'

    Terry Pratchett, The Last Continent

Short CV

I started studying computer science at the RWTH Aachen in 1989. I spent the academic year 1992/93 as an Erasmus exchange student at the University of Kent at Canterbury. I graduated in Aachen in June 1995, writing a dissertation about semantics of functional programs. From August 1995 to May 2000 I was employed as research & teaching assistant at the Lehrstuhl für Informatik II at the RWTH Aachen. There I obtained my PhD with a thesis about type-based deforestation of functional programs. Afterwards I came to the University of York as a research associate. Together with Colin Runciman and Malcolm Wallace I developed the Haskell tracer Hat. In 2002 I became a teaching fellow in York. In 2004 I became lecturer at the University of Kent.
As the Lecturer [...] put it: `He [the Archchancellor] called me in and asked me what I did, exactly. Have you ever heard of such a thing? What sort of question is that? This is a university!'
    Terry Pratchett, The Last Continent
Besides computer science I enjoy walking, reading, gardening (recent!), bicycle-riding, visiting historical sites and travelling in general.

School of Computing, University of Kent, Canterbury, Kent, CT2 7NF

Enquiries: +44 (0)1227 824180 or contact us.

Last Updated: 29/06/2017