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|
#! /bin/sh
#
# runlex.sh
# Script to run Lex/Flex.
# First argument is the (quoted) name of the command; if it's null, that
# means that neither Flex nor Lex was found, so we report an error and
# quit.
#
#
# Get the name of the command to run, and then shift to get the arguments.
#
if [ $# -eq 0 ]
then
echo "Usage: runlex <lex/flex command to run> [ arguments ]" 1>&2
exit 1
fi
LEX="$1"
shift
#
# Check whether we have Lex or Flex.
#
if [ -z "${LEX}" ]
then
echo "Neither lex nor flex was found" 1>&2
exit 1
fi
#
# Process the flags. We don't use getopt because we don't want to
# embed complete knowledge of what options are supported by Lex/Flex.
#
flags=""
outfile=lex.yy.c
while [ $# -ne 0 ]
do
case "$1" in
-o*)
#
# Set the output file name.
#
outfile=`echo "$1" | sed 's/-o\(.*\)/\1/'`
;;
-*)
#
# Add this to the list of flags.
#
flags="$flags $1"
;;
--|*)
#
# End of flags.
#
break
;;
esac
shift
done
#
# Is it Lex, or is it Flex?
#
if [ "${LEX}" = flex ]
then
#
# It's Flex.
#
have_flex=yes
#
# Does it support the --noFUNCTION options? If so, we pass
# --nounput, as at least some versions that support those
# options don't support disabling yyunput by defining
# YY_NO_UNPUT.
#
if flex --help | egrep noFUNCTION >/dev/null
then
flags="$flags --nounput"
#
# Does it support -R, for generating reentrant scanners?
# If so, we're not currently using that feature, but
# it'll generate some unused functions anyway - and there
# won't be any header file declaring them, so there'll be
# defined-but-not-declared warnings. Therefore, we use
# --noFUNCTION options to suppress generating those
# functions.
#
if flex --help | egrep reentrant >/dev/null
then
flags="$flags --noyyget_lineno --noyyget_in --noyyget_out --noyyget_leng --noyyget_text --noyyset_lineno --noyyset_in --noyyset_out"
fi
fi
else
#
# It's Lex.
#
have_flex=no
fi
#
# OK, run it.
# If it's lex, it doesn't support -o, so we just write to
# lex.yy.c and, if it succeeds, rename it to the right name,
# otherwise we remove lex.yy.c.
# If it's flex, it supports -o, so we use that - flex with -P doesn't
# write to lex.yy.c, it writes to a lex.{prefix from -P}.c.
#
if [ $have_flex = yes ]
then
${LEX} $flags -o"$outfile" "$@"
#
# Did it succeed?
#
status=$?
if [ $status -ne 0 ]
then
#
# No. Exit with the failing exit status.
#
exit $status
fi
#
# Flex has the annoying habit of stripping all but the last
# component of the "-o" flag argument and using that as the
# place to put the output. This gets in the way of building
# in a directory different from the source directory. Try
# to work around this.
#
# Is the outfile where we think it is?
#
outfile_base=`basename "$outfile"`
if [ "$outfile_base" != "$outfile" -a \( ! -r "$outfile" \) -a -r "$outfile_base" ]
then
#
# No, it's not, but it is in the current directory. Put it
# where it's supposed to be.
#
mv "$outfile_base" "$outfile"
#
# Did that succeed?
#
status=$?
if [ $status -ne 0 ]
then
#
# No. Exit with the failing exit status.
#
exit $status
fi
fi
else
${LEX} $flags "$@"
#
# Did it succeed?
#
status=$?
if [ $status -ne 0 ]
then
#
# No. Get rid of any lex.yy.c file we generated, and
# exit with the failing exit status.
#
rm -f lex.yy.c
exit $status
fi
#
# OK, rename lex.yy.c to the right output file.
#
mv lex.yy.c "$outfile"
#
# Did that succeed?
#
status=$?
if [ $status -ne 0 ]
then
#
# No. Get rid of any lex.yy.c file we generated, and
# exit with the failing exit status.
#
rm -f lex.yy.c
exit $status
fi
fi
#
# OK, now let's generate a header file declaring the relevant functions
# defined by the .c file; if the .c file is .../foo.c, the header file
# will be .../foo.h.
#
# This works around some other Flex suckage, wherein it doesn't declare
# the lex routine before defining it, causing compiler warnings.
# XXX - newer versions of Flex support --header-file=, to generate the
# appropriate header file. With those versions, we should use that option.
#
#
# Get the name of the prefix; scan the source files for a %option prefix
# line. We use the last one.
#
prefix=`sed -n 's/%option[ ][ ]*prefix="\(.*\)".*/\1/p' "$@" | tail -1`
if [ ! -z "$prefix" ]
then
prefixline="#define yylex ${prefix}lex"
fi
#
# Construct the name of the header file.
#
header_file=`dirname "$outfile"`/`basename "$outfile" .c`.h
#
# Spew out the declaration.
#
cat <<EOF >$header_file
/* This is generated by runlex.sh. Do not edit it. */
$prefixline
#ifndef YY_DECL
#define YY_DECL int yylex(void)
#endif
YY_DECL;
EOF
|
