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#!/bin/sh
# Copyright (C) 2019-2022 Internet Systems Consortium, Inc. ("ISC")
#
# This Source Code Form is subject to the terms of the Mozilla Public
# License, v. 2.0. If a copy of the MPL was not distributed with this
# file, You can obtain one at http://mozilla.org/MPL/2.0/.
# Get BNF grammars from bison files
#
# This script takes 1 or 2 parameters:
#
# Basic usage:
# ./extract_bnf.sh <bison-file-base-name> - will generate BNF notation in plain text
#
# Markdown:
# ./extract_bnf.sh <bison-file-base-name> --markdown
# Check if there are one or two arguments
if [ $# -lt 1 ]; then
echo "extract_bnf.sh <bison-file-base-name> [--markdown <name>]"
exit 1
fi
markdown=0
if [ $# -eq 3 ] && [ "$2" = "--markdown" ]; then
markdown=1
md_name=$3
fi
# Get the output file
base=$1
output=
header="This grammar is generated from \`\`$(basename "${base}").yy\`\`. See ${md_name} for more details."
if [ -f "${base}.yy" ]; then
# We want to explicitly set the language to English. Otherwise
# bison may produce language specific wording (like "symbole terminalne"
# if you system is set to Polish, rather than "Terminals") and this will
# confuse our script.
LANG=en_US LANGUAGE=en_US @YACC@ -v "${base}.yy" -o output
rm -f output output.h *.hh
mv output.output /tmp/output
output=/tmp/output
else
echo "cannot find ${base}.yy"
exit 1
fi
# Process the output file
# - extract the grammar part
# - remove line numbers
# - remove intermediate productions
# - remove intermediate non-terminals
# - replace standard tokens
# - replace : by BNF ::=
# - squeeze multiple blank lines
cat $output |\
@AWK@ '/^Terminal/ { exit }; // { print }' |\
@AWK@ '// { gsub("^ +[0-9]+ ", ""); print }' |\
@AWK@ '/^\$@[0-9]+:/ { next }; // { print }' |\
@AWK@ '// { gsub(" \\$@[0-9]+ ", " ") ; print }' |\
@AWK@ '// { gsub("\"constant string\"", "STRING"); print }' |\
@AWK@ '// { gsub("\"integer\"", "INTEGER"); print }' |\
@AWK@ '// { gsub("\"floating point\"", "FLOAT"); print }' |\
@AWK@ '// { gsub("\"boolean\"", "BOOLEAN"); print }' |\
@AWK@ '// { gsub("\"null\"", "NULL"); print }' |\
@AWK@ '// { gsub("\"constant hexstring\"", "HEXSTRING"); print }' |\
@AWK@ '// { gsub("\"option name\"", "OPTION_NAME"); print }' |\
@AWK@ '// { gsub("\"ip address\"", "IP_ADDRESS"); print }' |\
@AWK@ '// { gsub("\"end of file\"", "EOF"); print }' |\
@AWK@ '// { gsub("%empty", ""); print }' |\
@AWK@ '// { gsub(": ", " ::= "); print }' |\
cat -s > $output.2
if [ "$markdown" -eq 1 ]; then
cat > $output.3 << EOF
$header
.. code-block:: BNF
:linenos:
EOF
cat $output.2 | @AWK@ '/^.+$/ { print " ",$0 }; /^$/ { print } ' >> $output.3
cat $output.3
else
cat $output.2
fi
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