Bachelor Thesis of Dennis Felsing

Karlsruhe Institute of Technology
At the Department of Informatics
Institute for Program Structures and Data Organization (IPD)
Reviewer: Prof. Gregor Snelting
Advisor: Joachim Breitner


This thesis details the motivation, implementation and evaluation of ghc-vis, a tool for visualizing Haskell data structures inside of GHCi and GHC compiled programs at runtime. The layout of objects on the GHC heap is used as the basis for two types of visualizations, which respectively aim to functionally be supersets of GHCi’s :print and vacuum-cairo. Examples for using ghc-vis to further the understanding of lazy evaluation and sharing in Haskell are given.

The visualization of sharing and lazy evaluation in Haskell data structures can be useful to enhance the comprehension of functional data structures and algorithms and their perfomance in the environment of education, development and debugging.

A new library for parsing and viewing graphs in Haskell, called xdot, was created in order to interactively view graphs created by Graphviz.