[Haskell-cafe] :Trace has no history

Steve sseveran at gmail.com
Tue Aug 31 11:30:04 EDT 2010


I am trying to debug a problem in GHCI. I invoke my method with trace
but when it breaks on exception i can't get this history. Output is
below. Thanks.


relude Symbols> :set -fbreak-on-exception
Prelude Symbols> :trace myMethod
Loading package HUnit-1.2.2.1 ... linking ... done.
Loading package syb-0.1.0.2 ... linking ... done.
Loading package base-3.0.3.2 ... linking ... done.
Loading package old-locale-1.0.0.2 ... linking ... done.
Loading package time-1.1.4 ... linking ... done.
Loading package random-1.0.0.2 ... linking ... done.
Loading package QuickCheck-1.2.0.0 ... linking ... done.
Loading package Decimal-0.1.0 ... linking ... done.
Loading package array-0.3.0.0 ... linking ... done.
Loading package Diff-0.1.2 ... linking ... done.
Loading package bytestring-0.9.1.5 ... linking ... done.
Loading package containers-0.3.0.0 ... linking ... done.
Loading package mtl-1.1.0.2 ... linking ... done.
Loading package old-time-1.0.0.3 ... linking ... done.
Loading package convertible-1.0.9 ... linking ... done.
Loading package utf8-string-0.3.4 ... linking ... done.
Loading package HDBC-2.2.6 ... linking ... done.
Loading package HDBC-mysql-0.6.3 ... linking ... done.
Loading package parsec-2.1.0.1 ... linking ... done.
Loading package network-2.2.1.7 ... linking ... done.
Loading package HTTP-4000.0.9 ... linking ... done.
Loading package binary-0.5.0.2 ... linking ... done.
Loading package digest-0.0.0.8 ... linking ... done.
Loading package filepath-1.1.0.3 ... linking ... done.
Loading package unix-2.4.0.0 ... linking ... done.
Loading package directory-1.0.1.0 ... linking ... done.
Loading package pretty-1.0.1.1 ... linking ... done.
Loading package zlib-0.5.2.0 ... linking ... done.
Loading package zip-archive-0.1.1.6 ... linking ... done.
Loading package Core-0.0.1 ... linking ... done.
Beginning Update
Stopped at <exception thrown>
_exception ::
 e = GHC.Exception.SomeException (GHC.Exception.D:Exception _

(GHC.Show.D:Show ...) ....)
                                 (GHC.IO.Exception.IOError Nothing
GHC.IO.Exception.UserError ....)
[<exception thrown>] Prelude Symbols> :history
Empty history. Perhaps you forgot to use :trace?


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