Class: MessageFormat::Parser

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

Defined Under Namespace

Classes: SyntaxError

Class Method Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize ⇒ Parser

Returns a new instance of Parser.



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# File 'lib/message_format/parser.rb', line 21

def initialize ()
  @pattern = nil
  @length = 0
  @index = 0
end

Class Method Details

.parse(pattern) ⇒ Object 



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# File 'lib/message_format/parser.rb', line 353

def self.parse ( pattern )
  Parser.new().parse(pattern)
end

Instance Method Details

#error_message(expected = nil, found) ⇒ Object 



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# File 'lib/message_format/parser.rb', line 347

def error_message ( expected=nil, found )
  expected ?
    "Expected \"#{ expected }\" but found \"#{ found }\"" :
    "Unexpected \"#{ found }\" found" 
end

#is_digit(char) ⇒ Object 



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# File 'lib/message_format/parser.rb', line 38

def is_digit ( char )
  char == '0' or
  char == '1' or
  char == '2' or
  char == '3' or
  char == '4' or
  char == '5' or
  char == '6' or
  char == '7' or
  char == '8' or
  char == '9'
end

#is_whitespace(char) ⇒ Object 



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# File 'lib/message_format/parser.rb', line 51

def is_whitespace ( char )
  char == "\s" or
  char == "\t" or
  char == "\n" or
  char == "\r" or
  char == "\f" or
  char == "\v" or
  char == "\u00A0" or
  char == "\u2028" or
  char == "\u2029"
end

#parse(pattern) ⇒ Object 



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# File 'lib/message_format/parser.rb', line 27

def parse ( pattern )
  if !pattern.is_a?(String)
    raise_expected('String pattern', pattern.class.to_s)
  end

  @pattern = pattern
  @length = pattern.length
  @index = 0
  parse_message("message")
end

#parse_arg_id ⇒ Object 



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# File 'lib/message_format/parser.rb', line 179

def parse_arg_id ()
  skip_whitespace()
  id = ''
  while @index < @length
    char = @pattern[@index]
    if char == '{' or char == '#'
      raise_expected('argument id')
    end
    if char == '}' or char == ',' or is_whitespace(char)
      break
    end
    id += char
    @index += 1
  end
  if id.empty?
    raise_expected('argument id')
  end
  skip_whitespace()
  id
end

#parse_arg_type ⇒ Object 



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# File 'lib/message_format/parser.rb', line 200

def parse_arg_type ()
  skip_whitespace()
  arg_type = nil
  types = [
    'number', 'date', 'time', 'ordinal', 'duration', 'spellout', 'plural', 'selectordinal', 'select'
  ]
  types.each do |type|
    if @pattern.slice(@index, type.length) == type
      arg_type = type
      @index += type.length
      break
    end
  end
  if !arg_type
    raise_expected(types.join(', '))
  end
  skip_whitespace()
  arg_type
end

#parse_argument ⇒ Object 



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# File 'lib/message_format/parser.rb', line 122

def parse_argument ()
  if @pattern[@index] == '#'
    @index += 1 # move passed #
    return [ '#' ]
  end

  @index += 1 # move passed {
  id = parse_arg_id()
  char = @pattern[@index]
  if char == '}' # end argument
    @index += 1 # move passed }
    return [ id ]
  end
  if char != ','
    raise_expected(',')
  end
  @index += 1 # move passed ,

  type = parse_arg_type()
  char = @pattern[@index]
  if char == '}' # end argument
    if (
      type == 'plural' or
      type == 'selectordinal' or
      type == 'select'
    )
      raise_expected(type + ' message options')
    end
    @index += 1 # move passed }
    return [ id, type ]
  end
  if char != ','
    raise_expected(',')
  end
  @index += 1 # move passed ,

  format = nil
  offset = nil
  if type == 'plural' or type == 'selectordinal'
    offset = parse_plural_offset()
    format = parse_sub_messages(type)
  elsif type == 'select'
    format = parse_sub_messages(type)
  else
    format = parse_simple_format()
  end
  char = @pattern[@index]
  if char != '}' # not ended argument
    raise_expected('}')
  end
  @index += 1 # move passed

  (type == 'plural' or type == 'selectordinal') ?
    [ id, type, offset, format ] :
    [ id, type, format ]
end

#parse_message(parent_type) ⇒ Object 



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# File 'lib/message_format/parser.rb', line 310

def parse_message ( parent_type )
  elements = []
  text = parse_text(parent_type)
  if !text.empty?
    elements.push(text)
  end
  while @index < @length
    if @pattern[@index] == '}'
      if parent_type == 'message'
        raise_expected()
      end
      break
    end
    elements.push(parse_argument())
    text = parse_text(parent_type)
    if !text.empty?
      elements.push(text)
    end
  end
  elements
end

#parse_plural_offset ⇒ Object 



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# File 'lib/message_format/parser.rb', line 230

def parse_plural_offset ()
  skip_whitespace()
  offset = 0
  if @pattern.slice(@index, 7) == 'offset:'
    @index += 7 # move passed offset:
    skip_whitespace()
    start = @index
    while (
      @index < @length and
      is_digit(@pattern[@index])
    )
      @index += 1
    end
    if start == @index
      raise_expected('offset number')
    end
    offset = @pattern[start..@index].to_i
    skip_whitespace()
  end
  offset
end

#parse_selector ⇒ Object 



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# File 'lib/message_format/parser.rb', line 275

def parse_selector ()
  selector = ''
  while @index < @length
    char = @pattern[@index]
    if char == '}' or char == ','
      raise_expected('{')
    end
    if char == '{' or is_whitespace(char)
      break
    end
    selector += char
    @index += 1
  end
  if selector.empty?
    raise_expected('selector')
  end
  skip_whitespace()
  selector
end

#parse_simple_format ⇒ Object 



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# File 'lib/message_format/parser.rb', line 220

def parse_simple_format ()
  skip_whitespace()
  style = parse_text('style')
  if style.empty?
    raise_expected('argument style name')
  end
  skip_whitespace()
  style
end

#parse_sub_message(parent_type) ⇒ Object 



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# File 'lib/message_format/parser.rb', line 295

def parse_sub_message ( parent_type )
  char = @pattern[@index]
  if char != '{'
    raise_expected('{')
  end
  @index += 1 # move passed {
  message = parse_message(parent_type)
  char = @pattern[@index]
  if char != '}'
    raise_expected('}')
  end
  @index += 1 # move passed }
  message
end

#parse_sub_messages(parent_type) ⇒ Object 



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# File 'lib/message_format/parser.rb', line 252

def parse_sub_messages ( parent_type )
  skip_whitespace()
  options = {}
  has_subs = false
  while (
    @index < @length and
    @pattern[@index] != '}'
  )
    selector = parse_selector()
    skip_whitespace()
    options[selector] = parse_sub_message(parent_type)
    has_subs = true
    skip_whitespace()
  end
  if !has_subs
    raise_expected(parent_type + ' message options')
  end
  if !options.has_key?('other') # does not have an other selector
    raise_expected(nil, nil, '"other" option must be specified in ' + parent_type)
  end
  options
end

#parse_text(parent_type) ⇒ Object 



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# File 'lib/message_format/parser.rb', line 69

def parse_text ( parent_type )
  is_hash_special = (parent_type == 'plural' or parent_type == 'selectordinal')
  is_arg_style = (parent_type == 'style')
  text = ''
  while @index < @length
    char = @pattern[@index]
    if (
      char == '{' or
      char == '}' or
      (is_hash_special and char == '#') or
      (is_arg_style and is_whitespace(char))
    )
      break
    elsif char == '\''
      @index += 1
      char = @pattern[@index]
      if char == '\'' # double is always 1 '
        text += char
        @index += 1
      elsif (
        # only when necessary
        char == '{' or
        char == '}' or
        (is_hash_special and char == '#') or
        (is_arg_style and is_whitespace(char))
      )
        text += char
        while @index + 1 < @length
          @index += 1
          char = @pattern[@index]
          if @pattern.slice(@index, 2) == '\'\'' # double is always 1 '
            text += char
            @index += 1
          elsif char == '\'' # end of quoted
            @index += 1
            break
          else
            text += char
          end
        end
      else # lone ' is just a '
        text += '\''
        # already incremented
      end
    else
      text += char
      @index += 1
    end
  end

  text
end

#raise_expected(expected = nil, found = nil, message = nil) ⇒ Object

Raises:



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# File 'lib/message_format/parser.rb', line 332

def raise_expected ( expected=nil, found=nil, message=nil )
  lines = @pattern[0..@index].split(/\r?\n/)
  line = lines.length
  column = lines.last.length
  if !found
    found = @index < @length ? @pattern[@index] : 'end of input'
  end
  if !message
    message = error_message(expected, found)
  end
  message += ' in "' + @pattern.gsub(/\r?\n/, "\n") + '"'

  raise SyntaxError.new(message, expected, found, @index, line, column)
end

#skip_whitespace ⇒ Object 



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# File 'lib/message_format/parser.rb', line 63

def skip_whitespace ()
  while @index < @length and is_whitespace(@pattern[@index])
    @index += 1
  end
end