.TH HAT-TRANS 1 local
.SH NAME
hat-trans \- transform a Haskell module for tracing with the Hat system
.SH SYNOPSIS
.B hat-trans
[\-cpp [cppopts]]
[\-Idir]*
[\-package p]*
[transopts]
.I Mod.[l]hs ...
.SH DESCRIPTION
.I hat-trans
is a batch tool for transforming a Haskell program into one which
calculates its own trace.  It transforms each source module
.I Mod
supplied as arguments.  The modules may be ordinary source (.hs)
or literate source (.lhs).  The output is a transformed module,
whose name is the original module name prefixed with "Hat.", and it
is written to a file of similar name in the local subdirectory
.I Hat/
(except that .lhs becomes .hs, because the literate part is stripped).
If the subdirectory does not exist, it is created.  The original
source filename may include a directory path, in which case the
transformed module is placed in an identical directory tree underneath
the directory
.I Hat/.
This facilitates the easy transformation of modules within the
hierarchical module namespace.

The resulting transformed modules can be compiled and linked in the
normal way with your favorite Haskell compiler, with the addition
of the option
.I \-package hat
to its command-line.

Alternatively, rather than invoking
.I hat-trans
and a compiler by hand on your source files, but it is often more
convenient to allow
.I hmake(1)
to invoke the tools automatically, especially because it also
determines dependencies between modules and attempts to perform
the minimum re-compilation necessary.  Simple give the extra option
"-hat" to hmake.

.SH GENERAL OPTIONS
.TP
.B \-Idir
Use the directory
.I dir
as an additional root when searching for imported modules.
.TP
.B \-package p
The given source module(s) use standard modules from within the package
.I p
(this automatically adds the installed package root directory to the
import search path).
.TP
.B \-cpp
Invoke the C preprocessor on the source code before it is transformed.
This is useful for conditional transformation.
One cpp symbol is predefined, __HAT__, whose value is the version
number of the Hat toolset, expressed as a three digit integer, e.g.
version 2.02 gives __HAT__=202.  If the -cpp option is given, the
preprocessor is invoked on all the files given as arguments.  An
alternative which only invokes cpp on the files that really need it,
is to place a Haskell comment containing the string "-cpp" as the
first line of a source file.
.TP
.B \-Dsym=val
Define the cpp symbol
.I sym
to have the value
.I val
.TP
.B \-Dsym
Define the cpp symbol
.I sym
.TP
.B \-Usym
Undefine the cpp symbol
.I sym

.SH TRANSFORMATION OPTIONS
The following options are available to change the usual transformation
behaviour.
.TP
.B \-unlit
Unliterate the source code.  (Automatic if the file is .lhs)
.TP
.B \-nounlit
Do not unliterate the source code.  (Automatic if the file is .hs)
.TP
.B \-underscore
Treat underscores strictly as lowercase (default).
.TP
.B \-nounderscore
Treat underscores as invisible, e.g. _f is varid, _F is conid.
.TP
.B \-prelude
Treat prelude definitions specially.
.TP
.B \-noprelude
Do not treat definitions specially (default).
.TP
.B \-trusted
Make this a "trusted" module.
.TP
.B \-notrusted
Make this an "untrusted" module (default).
.TP
.B \-showwidth=w
Set output width (in characters) to
.I w
(default=80).
.TP
.B \-showindent=i
Set layout nesting indentation (in characters) to
.I i
(default=2).
.TP
.B \-showqualified
Use fully qualified names in the output.  This is off by default,
because the output may refer to modules which are not explicitly
imported.

.SH EXAMINATION OPTIONS
The following options are available to examine the internal progress
of the transformation.
.TP
.B \-lex
Show input after lexical analysis.
.TP
.B \-parse
Show syntax tree after parsing.
.TP
.B \-tracefns
Show syntax tree after tracing translation.

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

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