new

# File lib/scanf.rb, line 331
    def initialize(str)
      @spec_string = str
      h = '[A-Fa-f0-9]'

      @re_string, @handler = 
        case @spec_string

          # %[[:...:]]
        when /%\*?(\[\[:[a-z]+:\]\])/
          [ "(#{$1}+)", :extract_plain ]

          # %5[[:...:]]
        when /%\*?(\d+)(\[\[:[a-z]+:\]\])/
          [ "(#{$2}{1,#{$1}})", :extract_plain ]

          # %[...]
        when /%\*?\[([^\]]*)\]/
          yes = $1
          if /^\^/.match(yes) then no = yes[1..-1] else no = '^' + yes end
          [ "([#{yes}]+)(?=[#{no}]|\\z)", :extract_plain ]

          # %5[...]
        when /%\*?(\d+)\[([^\]]*)\]/
          yes = $2
          w = $1
          [ "([#{yes}]{1,#{w}})", :extract_plain ]

          # %i
        when /%\*?i/
          [ "([-+]?(?:(?:0[0-7]+)|(?:0[Xx]#{h}+)|(?:[1-9]\\d+)))", :extract_integer ]

          # %5i
        when /%\*?(\d+)i/
          n = $1.to_i
          s = "("
          if n > 1 then s += "[1-9]\\d{1,#{n-1}}|" end
          if n > 1 then s += "0[0-7]{1,#{n-1}}|" end
          if n > 2 then s += "[-+]0[0-7]{1,#{n-2}}|" end
          if n > 2 then s += "[-+][1-9]\\d{1,#{n-2}}|" end
          if n > 2 then s += "0[Xx]#{h}{1,#{n-2}}|" end
          if n > 3 then s += "[-+]0[Xx]#{h}{1,#{n-3}}|" end
          s += "\\d"
          s += ")"
          [ s, :extract_integer ]

          # %d, %u
        when /%\*?[du]/
          [ '([-+]?\d+)', :extract_decimal ]

          # %5d, %5u
        when /%\*?(\d+)[du]/
          n = $1.to_i
          s = "("
          if n > 1 then s += "[-+]\\d{1,#{n-1}}|" end
          s += "\\d{1,#{$1}})"
          [ s, :extract_decimal ]

          # %x
        when /%\*?[Xx]/
          [ "([-+]?(?:0[Xx])?#{h}+)", :extract_hex ]

          # %5x
        when /%\*?(\d+)[Xx]/
          n = $1.to_i
          s = "("
          if n > 3 then s += "[-+]0[Xx]#{h}{1,#{n-3}}|" end
          if n > 2 then s += "0[Xx]#{h}{1,#{n-2}}|" end
          if n > 1 then s += "[-+]#{h}{1,#{n-1}}|" end
          s += "#{h}{1,#{n}}"
          s += ")"
          [ s, :extract_hex ]

          # %o
        when /%\*?o/
          [ '([-+]?[0-7]+)', :extract_octal ]

          # %5o
        when /%\*?(\d+)o/
          [ "([-+][0-7]{1,#{$1.to_i-1}}|[0-7]{1,#{$1}})", :extract_octal ]

          # %f
        when /%\*?f/
          [ '([-+]?((\d+(?>(?=[^\d.]|$)))|(\d*(\.(\d*([eE][-+]?\d+)?)))))', :extract_float ]

          # %5f
        when /%\*?(\d+)f/
          [ "(\\S{1,#{$1}})", :extract_float ]

          # %5s
        when /%\*?(\d+)s/
          [ "(\\S{1,#{$1}})", :extract_plain ]

          # %s
        when /%\*?s/
          [ '(\S+)', :extract_plain ]

          # %c
        when /\s%\*?c/
          [ "\\s*(.)", :extract_plain ]

          # %c
        when /%\*?c/
          [ "(.)", :extract_plain ]

          # %5c (whitespace issues are handled by the count_*_space? methods)
        when /%\*?(\d+)c/
          [ "(.{1,#{$1}})", :extract_plain ]

          # %%
        when /%%/
          [ '(\s*%)', :nil_proc ]

          # literal characters
        else
          [ "(#{Regexp.escape(@spec_string)})", :nil_proc ]
        end

      @re_string = '\A' + @re_string
    end