Class: Scanf::FormatSpecifier

Inherits:
Object
  • Object
show all
Defined in:
lib/scanf.rb

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(str) ⇒ FormatSpecifier

Returns a new instance of FormatSpecifier.



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# 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

Instance Attribute Details

#conversion ⇒ Object (readonly)

Returns the value of attribute conversion



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# File 'lib/scanf.rb', line 306

def conversion
  @conversion
end

#matched ⇒ Object (readonly)

Returns the value of attribute matched



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# File 'lib/scanf.rb', line 306

def matched
  @matched
end

#matched_string ⇒ Object (readonly)

Returns the value of attribute matched_string



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# File 'lib/scanf.rb', line 306

def matched_string
  @matched_string
end

#re_string ⇒ Object (readonly)

Returns the value of attribute re_string



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# File 'lib/scanf.rb', line 306

def re_string
  @re_string
end

Instance Method Details

#count_space? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/scanf.rb', line 327

def count_space?
  /(?:\A|\S)%\*?\d*c|\[/.match(@spec_string)
end

#letter ⇒ Object 



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# File 'lib/scanf.rb', line 468

def letter
  /%\*?\d*([a-z\[])/.match(@spec_string).to_a[1]
end

#match(str) ⇒ Object 



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# File 'lib/scanf.rb', line 455

def match(str)
  @matched = false
  s = str.dup
  s.sub!(/\A\s+/,'') unless count_space?
  res = to_re.match(s)
  if res
    @conversion = send(@handler, res[1])
    @matched_string = @conversion.to_s
    @matched = true
  end
  res
end

#mid_match? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/scanf.rb', line 477

def mid_match?
  return false unless @matched
  cc_no_width    = letter == '[' &&! width
  c_or_cc_width  = (letter == 'c' || letter == '[') && width
  width_left     = c_or_cc_width && (matched_string.size < width)

  return width_left || cc_no_width
end

#to_re ⇒ Object 



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# File 'lib/scanf.rb', line 451

def to_re
  Regexp.new(@re_string,Regexp::MULTILINE)
end

#to_s ⇒ Object 



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# File 'lib/scanf.rb', line 323

def to_s
  @spec_string
end

#width ⇒ Object 



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# File 'lib/scanf.rb', line 472

def width
  w = /%\*?(\d+)/.match(@spec_string).to_a[1]
  w && w.to_i
end