Class: RubyLex::BufferedReader

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

When the lexer encounters the <<A, it reads until the end of the line, and keeps it around for later. It then reads the body of the here document. Once complete, it needs to read the rest of the original line, but then skip the here document body.

Methods

column divert_read_from get_read getc getc_already_read new peek peek_equal ungetc

Attributes

line_num [R]

Public Class methods

new(content)

[Source]

# File rdoc/parsers/parse_rb.rb, line 348
    def initialize(content)
      if /\t/ =~ content
        tab_width = Options.instance.tab_width
        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

Public Instance methods

column()

[Source]

# File rdoc/parsers/parse_rb.rb, line 367
    def column
      @offset - @last_newline
    end

divert_read_from(reserve)

[Source]

# File rdoc/parsers/parse_rb.rb, line 421
    def divert_read_from(reserve)
      @content[@offset, 0] = reserve
      @size      = @content.size
    end

get_read()

[Source]

# File rdoc/parsers/parse_rb.rb, line 402
    def get_read
      res = @content[@read_back_offset...@offset]
      @read_back_offset = @offset
      res
    end

getc()

[Source]

# File rdoc/parsers/parse_rb.rb, line 371
    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

getc_already_read()

[Source]

# File rdoc/parsers/parse_rb.rb, line 390
    def getc_already_read
      getc
    end

peek(at)

[Source]

# File rdoc/parsers/parse_rb.rb, line 408
    def peek(at)
      pos = @offset + at
      if pos >= @size
        nil
      else
        @content[pos, 1]
      end
    end

peek_equal(str)

[Source]

# File rdoc/parsers/parse_rb.rb, line 417
    def peek_equal(str)
      @content[@offset, str.length] == str
    end

ungetc(ch)

[Source]

# File rdoc/parsers/parse_rb.rb, line 394
    def ungetc(ch)
      raise "unget past beginning of file" if @offset <= 0
      @offset -= 1
      if @content[@offset] == ?\n
        @newline_pending = false
      end
    end