Class: SDL4R::Parser::Reader

Inherits:
Object
  • Object
show all
Defined in:
lib/sdl4r/parser/reader.rb

Overview

Gives access to the characters read to the Parser. This class was designed to gather the handling of the UTF-8 issues in one place and shield the Parser class from these problems.

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(io) ⇒ Reader

io an open IO from which the characters are read.

Raises:

  • (ArgumentError) 


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# File 'lib/sdl4r/parser/reader.rb', line 31

def initialize(io)
  raise ArgumentError, "io == nil" if io.nil?

  @io = io
  @line = nil
  @line_chars = nil
  @line_no = 0
  @pos = 0
end

Instance Attribute Details

#line ⇒ Object (readonly)

Returns the value of attribute line.



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# File 'lib/sdl4r/parser/reader.rb', line 41

def line
  @line
end

#line_no ⇒ Object (readonly)

Returns the value of attribute line_no.



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# File 'lib/sdl4r/parser/reader.rb', line 41

def line_no
  @line_no
end

#pos ⇒ Object (readonly)

Returns the value of attribute pos.



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# File 'lib/sdl4r/parser/reader.rb', line 41

def pos
  @pos
end

Instance Method Details

#close ⇒ Object

Closes this Reader and its underlying IO.



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# File 'lib/sdl4r/parser/reader.rb', line 169

def close
  @io.close
end

#current_char ⇒ Object

Returns the character at the current position or nil after end-of-line or end-of -file.



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# File 'lib/sdl4r/parser/reader.rb', line 106

def current_char
  return get_line_char(@pos)
end

#end_of_file? ⇒ Boolean

Indicates whether the end of file has been reached.

Returns:

  • (Boolean) 


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# File 'lib/sdl4r/parser/reader.rb', line 68

def end_of_file?
  return @line.nil?
end

#end_of_line? ⇒ Boolean

Returns whether the end of the current line as been reached.

Returns:

  • (Boolean) 


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# File 'lib/sdl4r/parser/reader.rb', line 78

def end_of_line?
  return @pos >= line_length
end

#find_next_in_line(searched, start_pos = nil) ⇒ Object

Returns the next index of the expression (string, regexp, fixnum) in the current line, starting from after the current position if no position is specified.



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# File 'lib/sdl4r/parser/reader.rb', line 128

def find_next_in_line(searched, start_pos = nil)
  start_pos = @pos + 1 unless start_pos
  return @line.index(searched, start_pos)
end

#get_line_char(pos) ⇒ Object

Returns the character at position pos in the current line. Returns nil if there is no current line or if pos is after the end of the line.



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# File 'lib/sdl4r/parser/reader.rb', line 97

def get_line_char(pos)
  if @line_chars and pos < line_length
    return @line_chars[pos]
  else
    return nil
  end
end

#line_length ⇒ Object 



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# File 'lib/sdl4r/parser/reader.rb', line 43

def line_length
  return @line_chars.nil? ? 0 : @line_chars.length
end

#more_chars_in_line? ⇒ Boolean

Indicates whether there are more characters in the current line

Returns:

  • (Boolean) 


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# File 'lib/sdl4r/parser/reader.rb', line 73

def more_chars_in_line?
  return @pos < line_length - 1
end

#previous_char ⇒ Object

Returns to the previous char if possible.



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# File 'lib/sdl4r/parser/reader.rb', line 122

def previous_char
  @pos -= 1 if @pos >= -1
end

#read_char ⇒ Object

Go to the next character and returns it (or nil if end-of-line or -file has been reached).



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# File 'lib/sdl4r/parser/reader.rb', line 116

def read_char
  skip_char()
  return current_char
end

#read_line ⇒ Object

Reads next line in stream skipping comment lines and blank lines.

Returns the next line or nil at the end of the file.



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# File 'lib/sdl4r/parser/reader.rb', line 50

def read_line
  @line_chars = nil

  while @line = read_raw_line()
    # Skip empty and commented lines
    break unless @line.empty? or @line =~ /^#/
  end

  return @line
end

#read_raw_line ⇒ Object

Reads and returns a “raw” line including lines with comments and blank lines.

Returns the next line or nil if at the end of the file.

This method changes the value of @line, @lineNo and @pos.



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# File 'lib/sdl4r/parser/reader.rb', line 149

def read_raw_line
  @line = @io.gets()

  # We ensure that only \n is used as an end-of-line by replacing \r and \r\n.
  if @line
    if not @line.gsub!(/\r\n/m, "\n")
      @line.gsub!(/\r/m, "\n")
    end
  end

  @pos = 0;
  @line_chars = nil
  if @line
    @line_no += 1
    @line_chars = @line.scan(/./m)
  end
  return @line
end

#rest_of_line ⇒ Object

Returns the string that goes from the current position of this Reader to the end of the line or nil if the current position doesn’t allow that.



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# File 'lib/sdl4r/parser/reader.rb', line 63

def rest_of_line
  return @line[@pos..-1]
end

#skip_char ⇒ Object

Go to the next character in the stream.



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# File 'lib/sdl4r/parser/reader.rb', line 111

def skip_char
  @pos += 1 if @pos < line_length
end

#skip_line ⇒ Object

Skips the current line by going just after its end.



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# File 'lib/sdl4r/parser/reader.rb', line 83

def skip_line
  @pos = line_length
end

#skip_to(new_pos) ⇒ Object

Skips the specified position in the current line.



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# File 'lib/sdl4r/parser/reader.rb', line 134

def skip_to(new_pos)
  @pos = new_pos
end

#skip_whitespaces ⇒ Object

Skips the whitespaces that follow the current position.



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# File 'lib/sdl4r/parser/reader.rb', line 88

def skip_whitespaces
  while (@pos + 1) < line_length and
      (@line[@pos + 1] == ?\s or @line[@pos + 1] == ?\t)
    @pos += 1
  end
end

#substring(from, to = -1)) ⇒ Object

Returns a subpart of the current line starting from from and stopping at to (excluded).



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# File 'lib/sdl4r/parser/reader.rb', line 140

def substring(from, to = -1)
  return @line[from..to]
end