Program Understanding and Re-engineering: Calculi and Applications




Sep 18 Paper Towards a Coordination Model for Interactive Systems by MarcoAntonioBarbosa, JoseCampos and LuisSoaresBarbosa has been accepted for FMIS'06 (Macau).

July 3 Paper Configurations of Web Services by MarcoAntonioBarbosa and LuisSoaresBarbosa has been accepted for FOCLASA'06 (Bonn, Germany).

July 3 Paper Strong Types for Relational Databases by Alexandra Silva and JoostVisser has been accepted for the Haskell Workshop 2006 (Portland, USA).

June 16 Paper Strongly Typed Rewriting For Coupled Software Transformation (by AlcinoCunha and JoostVisser) accepted by RULE 2006 (Seattle, USA).

May, 26 Paper Transposing Partial Coalgebras (by LuisSoaresBarbosa and JoseNunoOliveira) accepted for publication in TCS, Elsevier.

May, 11 Papers Type-safe two-level data transformation (by AlcinoCunha, JoseNunoOliveira and JoostVisser) and Pointfree factorization of operation refinement (by JoseNunoOliveira and Cesar Rodrigues) have been accepted by FM'06 (Canada).

May, 8 A paper entitled An Orchestrator for Dynamic Interconnection of Software Components, by MarcoAntonioBarbosa and LuisSoaresBarbosa, accepted at MTCoord'06 (Bologna).


Pointless Haskell


Pointless Haskell is library for point-free programming with recursion patterns defined as hylomorphisms. It is part of the UMinho Haskell Libraries that are being developed in the Research.PURe project. The core of the library is described in the following paper.

It also allows the visualization of the intermediate data structure of the hylomorphisms with GHood. This feature toghether with the DrHylo tool allows us to easily visualize recursion trees of Haskell functions. We first implemented this ideas using Generic Haskell, as presented in WFLP'03. We now take a different approach to genericity based on Personal/Alcino.PolyP.


The latest snapshot of the UMinho Haskell Libraries can be downloaded here. The modules that comprise Pointless Haskell are the following.

Module Description
Pointless.Combinators Point-free programming combinators.
Pointless.Combinators.Uncurried Point-free definitions of uncurried versions of the basic combinators.
Pointless.Isomorphisms Auxiliary isomorphism definitions.
Pointless.Functors Definition of functors, generic maps, and sum-of-products representation.
Pointless.RecursionPatterns Definition of the typical recursion as hylomorphisms.
Pointless.Observe.Functors Definition of generic observations.
Pointless.Observe.RecursionPatterns Recursion patterns with observation of intermediate data structures.
Pointless.Examples.Examples Lots of examples.
Debug.Observe Slightly modified GHood library.


For the moment there is no documentation, but by reading the papers and looking at examples you should be able to learn it by yourself. It was only tested on GHC. I think that it should be easy to use it under Hugs.

Please send feedback to alcino@di.uminho.pt.



Tool for deriving hylomorphisms from a restricted Haskell syntax. It is based on the algorithm first presented in the paper Deriving Structural Hylomorphisms From Recursive Definitions at ICFP'96 by Hu, Iwasaki, and Takeichi.


See PUReSoftware.


To use DrHylo, simply type DrHylo -h at the command line, and follow instructions.

Usage: Personal/Alcino.DrHylo [OPTION...]
  -o[FILE]  --output[=FILE]  output FILE
  -i[FILE]  --input[=FILE]   input FILE

To run the resulting Haskell files you will need PointlessHaskell.

Please send feedback to alcino@di.uminho.pt.

Point-free Program Transformation

This is a project where I, José Proença, worked on since April until October 2005. It was supervised by Jorge Sousa Pinto and Alcino Cunha, who supported and helped me during this time. The proposal is explained in more detailed in here. The results can be found in my internship report, here.

The project consists on two parts:

  • Definition of two refactorings -- the conversion from point-wise to pointfree and the removal of guards;
  • Automatic simplification and transformation of pointfree expressions.

Refactorings in HaRe

In the begining of the project, I spent two weeks in Canterbury developing two refactorings to be part of HaRe:

A snapshot of the source code where these transformations are applied can be found here.

There are also some examples that can be found in the following links:

The SimpliFree Tool

Allows for the automatic simplification and some program transformation of Haskell code, written in a point-free style. The technical report is available here. The SimpliFree tool is now available in the Uminho Haskell Libraries, that can be downloaded from the CVS repository.

This tool uses Haskell pattern matching to apply rules, by creating an auxiliary file with the functions where the strategies, rules and the pointfree terms are defined. In spite of the fact that this approach meant to be simpler than most approaches where a pattern matching algorithm is defined, the definitions of functions that apply a rule were more complex than expected.

In September, this tool, together with the DrHylo tool and the Pointless library, were presented in IFL'05 workshop. The presentation "A Framework for Point-free Program Transformation", shown in this workshop, can be found here.

The SimpliFree tool was also presented in the PURe Workshop 2005. The slides can be found here.

r3 - 12 Feb 2007 - 19:59:24 - JoseBacelarAlmeida
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