1#!/bin/sh
2
3# Copyright (C) 2019-2021 Internet Systems Consortium, Inc. ("ISC")
4#
5# This Source Code Form is subject to the terms of the Mozilla Public
6# License, v. 2.0. If a copy of the MPL was not distributed with this
7# file, You can obtain one at http://mozilla.org/MPL/2.0/.
8
9# Get BNF grammars from bison files
10#
11# This script takes 1 or 2 parameters:
12#
13# Basic usage:
14# ./extract_bnf.sh <bison-file-base-name> - will generate BNF notation in plain text
15#
16# Markdown:
17# ./extract_bnf.sh <bison-file-base-name> --markdown
18
19# Check if there are one or two arguments
20if [ $# -lt 1 ]; then
21    echo "extract_bnf.sh <bison-file-base-name> [--markdown <name>]"
22    exit 1
23fi
24
25markdown=0
26if [ $# -eq 3 ] && [ "$2" = "--markdown" ]; then
27    markdown=1
28    md_name=$3
29fi
30
31# Get the output file
32base=$1
33output=
34now=$(date +"%Y-%m-%-d %H:%m")
35
36header="Grammar generated on $now. See Chapter $md_name for an explanation."
37
38if [ -f "${base}.yy" ]; then
39    # We want to explicitly set the language to English. Otherwise
40    # bison may produce language specific wording (like "symbole terminalne"
41    # if you system is set to Polish, rather than "Terminals") and this will
42    # confuse our script.
43    LANG=en_US LANGUAGE=en_US @YACC@ -v "${base}.yy" -o output
44    rm -f output output.h *.hh
45    mv output.output /tmp/output
46    output=/tmp/output
47else
48    echo "cannot find ${base}.yy"
49    exit 1
50fi
51
52# Process the output file
53#  - extract the grammar part
54#  - remove line numbers
55#  - remove intermediate productions
56#  - remove intermediate non-terminals
57#  - replace standard tokens
58#  - replace : by BNF ::=
59#  - squeeze multiple blank lines
60
61cat $output |\
62@AWK@ '/^Terminal/ { exit }; // { print }' |\
63@AWK@ '// { gsub("^ +[0-9]+ ", ""); print }' |\
64@AWK@ '/^\$@[0-9]+:/ { next }; // { print }' |\
65@AWK@ '// { gsub(" \\$@[0-9]+ ", " ") ; print }' |\
66@AWK@ '// { gsub("\"constant string\"", "STRING"); print }' |\
67@AWK@ '// { gsub("\"integer\"", "INTEGER"); print }' |\
68@AWK@ '// { gsub("\"floating point\"", "FLOAT"); print }' |\
69@AWK@ '// { gsub("\"boolean\"", "BOOLEAN"); print }' |\
70@AWK@ '// { gsub("\"null\"", "NULL"); print }' |\
71@AWK@ '// { gsub("\"constant hexstring\"", "HEXSTRING"); print }' |\
72@AWK@ '// { gsub("\"option name\"", "OPTION_NAME"); print }' |\
73@AWK@ '// { gsub("\"ip address\"", "IP_ADDRESS"); print }' |\
74@AWK@ '// { gsub("\"end of file\"", "EOF"); print }' |\
75@AWK@ '// { gsub("%empty", ""); print }' |\
76@AWK@ '// { gsub(": ", " ::= "); print }' |\
77cat -s > $output.2
78
79if [ "$markdown" -eq 1 ]; then
80    cat > $output.3 << EOF
81
82$header
83
84.. code-block:: BNF
85   :linenos:
86
87EOF
88    cat $output.2 | @AWK@ '/^.+$/ { print "    ",$0 }; /^$/ { print } ' >> $output.3
89    cat $output.3
90else
91    cat $output.2
92fi
93