Class: ANTLR3::UnicodeStream

Inherits:

StringStream

• Object
• StringStream
• ANTLR3::UnicodeStream

show all

Defined in:

lib/antlr3/streams/unicode.rb

Constant Summary

PACK_MASK =

'U*'.freeze

Constants inherited from StringStream

StringStream::NEWLINE

Constants included from Constants

Constants::BUILT_IN_TOKEN_NAMES, Constants::DEFAULT, Constants::DOWN, Constants::EOF, Constants::EOF_TOKEN, Constants::EOR_TOKEN_TYPE, Constants::HIDDEN, Constants::INVALID_TOKEN, Constants::INVALID_TOKEN_TYPE, Constants::MEMO_RULE_FAILED, Constants::MEMO_RULE_UNKNOWN, Constants::MIN_TOKEN_TYPE, Constants::SKIP_TOKEN, Constants::UP

Instance Attribute Summary

Attributes inherited from StringStream

#column, #data, #line, #name, #position, #string

Attributes included from CharacterStream

#column, #line

Attributes included from Stream

#size, #source_name

Instance Method Summary (collapse)

• - (Object) [](start, *args)

  identical to String#[].

• - (UnicodeStream) initialize(data, options = {}) constructor

  creates a new StringStream object where data is the string data to stream.

• - (Object) look(k = 1)

  identical to #peek, except it returns the character value as a String.

• - (Object) substring(start, stop)

  return the string slice between position start and stop.

• - (Object) through(k)

  return a substring around the stream cursor at a distance k if k >= 0, return the next k characters if k < 0, return the previous |k| characters.

Methods inherited from StringStream

#<<, #beginning_of_line?, #beginning_of_string?, #consume, #end_of_line?, #end_of_string?, #inspect, #last_marker, #mark, #mark_depth, #peek, #release, #reset, #rewind, #seek, #size

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# File 'lib/antlr3/streams/unicode.rb', line 25

def initialize( data, options = {} )    # for 1.8
  @string = data.to_s
  @string.equal?( data ) and @string = @string.clone
  @string.freeze
  @data = @string.unpack( PACK_MASK )
  @position = options.fetch :position, 0
  @line = options.fetch :line, 1
  @column = options.fetch :column, 0
  @markers = []
  @name ||= options[ :file ] || options[ :name ] # || '(string)'
  mark
end

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# File 'lib/antlr3/streams/unicode.rb', line 74

def []( start, *args )
  @data[ start, *args ].pack( PACK_MASK )
end

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# File 'lib/antlr3/streams/unicode.rb', line 41

def look( k = 1 )                        # for 1.8
  k == 0 and return nil
  k += 1 if k < 0
  
  index = @position + k - 1
  index.between?( 0, @data.length - 1) or return nil
  
  @data[ index, 1 ].pack( PACK_MASK )
end

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# File 'lib/antlr3/streams/unicode.rb', line 66

def substring( start, stop )
  @data[ start, stop - start + 1 ].pack( PACK_MASK )
end

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# File 'lib/antlr3/streams/unicode.rb', line 56

def through( k )
  if k >= 0 then @data[ @position, k ].pack( PACK_MASK ) else
    start = ( @position + k ).at_least( 0 ) # start cannot be negative or index will wrap around
    @data[ start ... @position ].pack( PACK_MASK )
  end
end