Class: YARD::Parser::Ruby::Legacy::RubyLex::BufferedReader

Inherits:
Object
  • Object
show all
Defined in:
lib/yard/parser/ruby/legacy/ruby_lex.rb

Overview

####################################################################

Read an input stream character by character. We allow for unlimited ungetting of characters just read.

We simplify the implementation greatly by reading the entire input into a buffer initially, and then simply traversing it using pointers.

We also have to allow for the here document diversion. This little gem comes about when the lexer encounters a here document. At this point we effectively need to split the input stream into two parts: one to read the body of the here document, the other to read the rest of the input line where the here document was initially encountered. For example, we might have 

  do_something(<<-A    stuff
    for
  A
, <<-B    stuff
    for
  B
)

When the lexer encounters the <

Instance Attribute Summary

Instance Method Summary

Constructor Details

- (BufferedReader) initialize(content)

A new instance of BufferedReader 



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# File 'lib/yard/parser/ruby/legacy/ruby_lex.rb', line 338

def initialize(content)
  if /\t/ =~ content
    tab_width = 2
    content = content.split(/\n/).map do |line|
      1 while line.gsub!(/\t+/) { ' ' * (tab_width*$&.length - $`.length % tab_width)}  && $~ #`
      line
    end .join("\n")
  end
  @content   = content
  @content << "\n" unless @content[-1,1] == "\n"
  @size      = @content.size
  @offset    = 0
  @hwm       = 0
  @line_num  = 1
  @read_back_offset = 0
  @last_newline = 0
  @newline_pending = false
end

Instance Attribute Details

- (Object) line_num (readonly)

Returns the value of attribute line_num 



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# File 'lib/yard/parser/ruby/legacy/ruby_lex.rb', line 336

def line_num
  @line_num
end

Instance Method Details

- (Object) column 



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# File 'lib/yard/parser/ruby/legacy/ruby_lex.rb', line 357

def column
  @offset - @last_newline
end

- (Object) divert_read_from(reserve) 



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# File 'lib/yard/parser/ruby/legacy/ruby_lex.rb', line 411

def divert_read_from(reserve)
  @content[@offset, 0] = reserve
  @size      = @content.size
end

- (Object) get_read 



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# File 'lib/yard/parser/ruby/legacy/ruby_lex.rb', line 392

def get_read
  res = @content[@read_back_offset...@offset]
  @read_back_offset = @offset
  res
end

- (Object) getc 



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# File 'lib/yard/parser/ruby/legacy/ruby_lex.rb', line 361

def getc
  return nil if @offset >= @size
  ch = @content[@offset, 1]
      
  @offset += 1
  @hwm = @offset if @hwm < @offset
      
  if @newline_pending
    @line_num += 1
    @last_newline = @offset - 1
    @newline_pending = false
  end
      
  if ch == "\n"
    @newline_pending = true
  end
  ch
end

- (Object) getc_already_read 



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# File 'lib/yard/parser/ruby/legacy/ruby_lex.rb', line 380

def getc_already_read
  getc
end

- (Object) peek(at) 



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# File 'lib/yard/parser/ruby/legacy/ruby_lex.rb', line 398

def peek(at)
  pos = @offset + at
  if pos >= @size
    nil
  else
    @content[pos, 1]
  end
end

- (Object) peek_equal(str) 



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# File 'lib/yard/parser/ruby/legacy/ruby_lex.rb', line 407

def peek_equal(str)
  @content[@offset, str.length] == str
end

- (Object) ungetc(ch) 



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# File 'lib/yard/parser/ruby/legacy/ruby_lex.rb', line 384

def ungetc(ch)
  raise "unget past beginning of file" if @offset <= 0
  @offset -= 1
  if @content[@offset] == ?\n
    @newline_pending = false
  end
end