# sed -E -f deyacc.sed foo.y
# ...will remove everything from a .y file except the grammar rules
#
# This file is part of Beastie <https://purl.org/nxg/dist/beastie>
# SPDX-FileCopyrightText: 2024 Norman Gray <https://nxg.me.uk>
# SPDX-License-Identifier: BSD-2-Clause

1,/^%%/d
/^%%/,$d

# protect '{' from the two following lines
s/'{'/LBRACE/g
/^[a-z]/s/[[:space:]]*(\{.*)?$//
/^ *\|/s/[[:space:]]*(\{.*)?$//

# restore LBRACE
s/LBRACE/'{'/g

# have we made any substitutions?  If so, skip the 'd'
t

# delete everthing not matched above
d