Projects / Hat


Hat (Haskell Tracer) is a tracing and debugging system for Haskell that can be used for comprehending working programs, and debugging an incorrect one. It consists of hat-trans, which transforms a program into one that traces itself using your normal compiler and a runtime library, and a set of browsing tools that explore the trace after execution of the program has completed.

Operating Systems

Recent releases

  •  17 May 2005 16:56

    Release Notes: Hat now supports compilers from ghc-5.04.2 and nhc98-1.18 upwards, including the entire ghc-6 series. There is support for more of the standard hierarchical libraries (but the tracing versions are still only a subset of the full list). Various other feature improvements include recording full source positions in the trace rather than just start-positions, and recording do-notation, meaning that visual linkage from the trace to your program is far more helpful. A range of experimental tracing tools is included.

    •  27 Mar 2003 21:07

      Release Notes: This release adds support for Haskell's hierarchical module namespaces, includes a tracing version of the base package of standard hierarchical libraries, supports several common type-system extensions such as MPTC, fundeps, and existentials, and also has a significant speed improvement of 20-40%. There are many minor bugfixes and user interface enhancements.

      •  29 Oct 2002 12:07

        No changes have been submitted for this release.


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