pdf_parslet.rb

require 'parslet'

class PdfParser < Parslet::Parser
  rule(:spaces) { match('\s').repeat(1) }
  rule(:spaces?) { spaces.maybe }
  rule(:integer) { match('[0-9]').repeat }
  rule(:separator) { str(":") }
  rule(:slash) { str("/") }
  rule(:rciwn_number) { integer >> slash >> integer }
  rule(:rciwn) { str("Number RCiWN") >> separator >> spaces? >> rciwn_number.as(:number) }
  root(:rciwn)
end

parser = PdfParser.new
p parser.parse("Number RCiWN: 123/32")