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# Author: Joe Touch / touch@strayalpha.com
# Last update: 7/15/2019

# adds XML <bcp14> tags around capitalized RFC2119 keywords and
# keyword phrases:
#	MUST
#	MUST NOT
#	REQUIRED
#	SHALL
#	SHALL NOT
#	SHOULD
#	SHOULD NOT
#	RECOMMENDED
#	MAY
#	OPTIONAL

# this version should run under any version of perl5

# pull in the entire file as a single line, suitable for multiline
# search/replace
my $line = do {local $/; <> };

# do the search and replace
$line =~ s/(\b(((MUST|SHOULD|SHALL)(\s+NOT)?)|((NOT\s+)?RECOMMENDED)|MAY|OPTIONAL|REQUIRED)\b)/<bcp14>$1<\/bcp14>/g;

# get rid of simple duplicates IF they are separted by only whitespace
$line =~ s/<bcp14>(\s*<bcp14>)/$1/ig;
$line =~ s/(<\/bcp14>\s*)<\/bcp14>/$1/ig;

# output the result
print $line;