#!/bin/sh
# Extract the initialization actions from source files.
#
#  Copyright (C) 1996, 97, 98, 99, 2000, 2001, 2002 Free Software Foundation, Inc.
#
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation; either version 2, or (at your option)
# any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this software; see the file COPYING.  If not, write to
# the Free Software Foundation, Inc., 59 Temple Place, Suite 330,
# Boston, MA 02111-1307 USA

# Commentary:

# Usage: guile-snarf [-o OUTFILE] [CPP-ARGS ...]
 
# Initialization actions are extracted to OUTFILE or to standard
# output when no OUTFILE has been specified or when OUTFILE is "-".
# The C preprocessor is called with CPP-ARGS (which usually include a
# input file) and the output is filtered for the actions.
# 
# If there are errors during processing, OUTFILE is deleted and the
# program exits with non-zero status.
# 
# During snarfing, the pre-processor macro SCM_MAGIC_SNARFER is
# defined.  You can use this to avoid including snarfer output files
# that don't yet exist by writing code like this:
# 
#   #ifndef SCM_MAGIC_SNARFER
#   #include "foo.x"
#   #endif
# 
# If the environment variable CPP is set, use its value instead of the
# C pre-processor determined at Guile configure-time: "gcc -E".

# Code:

## funcs

modern_snarf ()                         # writes stdout
{
    ## Apparently, AIX's preprocessor is unhappy if you try to #include an
    ## empty file.
    echo "/* cpp arguments: $@ */" ;
    ${cpp} -DSCM_MAGIC_SNARF_INITS -DSCM_MAGIC_SNARFER "$@" > ${temp} && cpp_ok_p=true
    grep "^ *\^ *\^" ${temp} | sed -e "s/^ *\^ *\^//"
}

## main

# process command line
if [ x"$1" = x--help ] ; then
    gawk '/^#.Commentary:/,/^#.Code:/' $0 | grep -v Code: \
        | sed -e 1,2d -e 's/^. *//g'
    exit 0
fi
if [ x"$1" = x-o ]
    then outfile="$2" ; shift ; shift ;
    else  outfile="-" ;
fi

# set vars and handler -- handle CPP override
cpp_ok_p=false
temp="/tmp/snarf.$$"
if [ x"$CPP" = x ] ; then cpp="gcc -E" ; else cpp="$CPP" ; fi

trap "rm -f $temp" 0 1 2 15

if [ ! "$outfile" = "-" ] ; then
    modern_snarf "$@" > $outfile
else
    modern_snarf "$@"
fi

# zonk outfile if errors occurred
if $cpp_ok_p ; then
    exit 0
else
    [ ! "$outfile" = "-" ] && rm -f $outfile
    exit 1
fi

# guile-snarf ends here
