.TH HAT-STACK 1 local
.SH NAME
hat-stack \- "virtual" stack trace for a crashed Haskell program
.SH SYNOPSIS
.B hat-stack
prog[.hat]
.SH DESCRIPTION
For aborted computations, that is computations that terminated
with an error message or were interrupted,
.I hat-stack
shows in which function call the computation was aborted.  It does
so by showing a virtual stack of function calls (redexes), i.e. every
function call on the stack caused the function call above it.  The
evaluation of the top stack element caused the error (or during
its evaluation the computation was interrupted).  The stack shown
is virtual, because it does not correspond to the actual runtime
stack.  The actual runtime stack enables lazy evaluation whereas the
virtual stack corresponds to a stack that would have been used for
eager (strict) evaluation.

.P
.B hat-stack
is now largely superseded by
.B hat-trail(1) which allows interactive browsing of the complete
call chain.

.SH FILES
.TP 25
.B @BINDIR@/hat-stack

.SH "SEE ALSO"
hmake(1), hat-trans(1), hat-observe(1), hat-detect(1), hat-trail(1)
