#! /bin/sh
# @configure_input@
#---------------------------------------------------------------------------#
# Copyright (C) 1995-1996 The University of Melbourne.
# This file may only be copied under the terms of the GNU General
# Public License - see the file COPYING in the Mercury distribution.
#---------------------------------------------------------------------------#
#
# This sed script is used to convert from Mercury to Sicstus Prolog
# It does three things: delete the `:- module' line,
# expand backslash escapes, and replace the use
# of `^' for xor in calls to is/2 with `#'.
# The expansion of backslash escapes includes support for
# "\c" line continuation sequences, whereby the sequence
#	backslash, "c", whitespace
# acts merely as layout text and is deleted from string literals;
# this allows string literals to extend over multiple lines, as in
#	X = "foo\c
#		bar".
# which is the same as X = "foobar".

# The commands for expanding \c are a bit complicated;
# here's an explanation.  
#
#       % this is the start of loop
#	:l
#		% if we see \c followed by any number of
#		% spaces, tabs, or embedded newlines (\n), and then finally
#		% followed by a non-embedded newline ($), we use the `N'
#		% command to read in the next line; we then branch to
#		% label `l' to start the loop again.
#		/\\c\( *	*\n*\)*$/{
#			N
#			b l
#		}
#		% at this point, we've read in all the lines of the \c
#		% command, so we replace the \c followed by any number of
#		% spaces, tabs, or embedded newlines (\n) with an empty
#		% string.
#		% 
#		/\\c\( *	*\n*\)*/s///g

for file in "$@"; do
	case $file in
		*.m) base=`basename "$file" .m` ;;
		*.nl) base=`basename "$file" .nl` ;;
		*) base=`basename "$file"` ;;
	esac
	# see comments above for explanation of this `sed' command
	sed -e '
		/ is /s/\^/#/g
		/^:- *module/d
		/^[ 	]*%/s/.*//
		/\\\\/s//\\/g
		/\\a/s///g
		/\\b/s///g
		/\\r/s//
/g
		/\\f/s///g
		/\\t/s//	/g
		/\\n/s//\
/g
		/\\v/s///g
	:l
		/\\c\( *	*\n*\)*$/{
			N
			b l
		}
		/\\c\( *	*\n*\)*/s///g
		' "$file" > "$base".pl
		# see comments above for explanation of this `sed' command
done