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# pass in any argument to assume we are processing for ripper instead
# of the main parser.
IS_RIPPER=!!ARGV.shift
def read_line
line = gets
return nil unless line
line.gsub(/@@([^@]+)@@/) do |word|
sub = SUBS[$1]
raise ArgumentError, "Cannot find substitution for #{word}" unless sub
sub[IS_RIPPER ? 1 : 0]
end
end
# We define substitutions at the top of the file where a constant
# named SUBS contains a key which represents a subtition and two value
# where the first value is what is substituted when writing the Parser
# and the second value is what is substituted when writing Ripper Parser.
#
# Any reference to @@name@@ will be replaced with first or second value
# later on in the grammar file.
def read_text_substitutions
code = ''
while line = read_line
break if line =~ %r{^=@@\*/}
code << line
end
# Reads in substitions into the constant SUBS
eval code
end
while line = read_line
if line =~ %r{^/\*@@=}
read_text_substitutions
else
puts line
end
end
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