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) 


31
32
33
34
35
36
37
38
39
 
# File 'lib/sdl4r/parser/reader.rb', line 31

def initialize(io)
  raise ArgumentError, "io == nil" unless io

  @io = io
  @line = nil
  @line_chars = nil
  @line_no = -1
  @pos = 0
end

Instance Attribute Details

#line ⇒ Object (readonly)

Returns the value of attribute line.



49
50
51
 
# File 'lib/sdl4r/parser/reader.rb', line 49

def line
  @line
end

#line_no ⇒ Object (readonly)

The current line no (zero-based)



42
43
44
 
# File 'lib/sdl4r/parser/reader.rb', line 42

def line_no
  @line_no
end

#pos ⇒ Object (readonly)

The position of the char currently pointed by this reader in the current line. This is not necessarily the position of the char you just got from a method, it might be the position of the next char, for instance.



47
48
49
 
# File 'lib/sdl4r/parser/reader.rb', line 47

def pos
  @pos
end

Instance Method Details

#close ⇒ Object

Closes this Reader and its underlying IO.



176
177
178
 
# File 'lib/sdl4r/parser/reader.rb', line 176

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.



114
115
116
 
# File 'lib/sdl4r/parser/reader.rb', line 114

def current_char
  return get_line_char(@pos)
end

#eof? ⇒ Boolean

Indicates whether the end of file has been reached.

Returns:

  • (Boolean) 


76
77
78
 
# File 'lib/sdl4r/parser/reader.rb', line 76

def eof?
  return @line.nil?
end

#eol? ⇒ Boolean

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

Returns:

  • (Boolean) 


86
87
88
 
# File 'lib/sdl4r/parser/reader.rb', line 86

def eol?
  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.



139
140
141
142
 
# File 'lib/sdl4r/parser/reader.rb', line 139

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.



105
106
107
108
109
110
111
 
# File 'lib/sdl4r/parser/reader.rb', line 105

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

#line_length ⇒ Object 



51
52
53
 
# File 'lib/sdl4r/parser/reader.rb', line 51

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 after the current char

Returns:

  • (Boolean) 


81
82
83
 
# File 'lib/sdl4r/parser/reader.rb', line 81

def more_chars_in_line?
  return @pos < line_length - 1
end

#previous_char ⇒ Object

Returns to the previous char if possible.



133
134
135
 
# File 'lib/sdl4r/parser/reader.rb', line 133

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

#read_char ⇒ Object

Returns the current char and go to the next. Returns nil if end-of-line or -file has been reached.



126
127
128
129
130
 
# File 'lib/sdl4r/parser/reader.rb', line 126

def read_char
  c = current_char
  skip_char()
  c
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.



58
59
60
61
62
63
64
65
66
67
 
# File 'lib/sdl4r/parser/reader.rb', line 58

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.



160
161
162
163
164
165
166
167
168
169
170
171
172
173
 
# File 'lib/sdl4r/parser/reader.rb', line 160

def read_raw_line
  @line = @io.gets()

  # Remove a possible \r at the end of line
  @line.gsub!(/\r+$/, "") if @line

  @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.



71
72
73
 
# File 'lib/sdl4r/parser/reader.rb', line 71

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

#skip_char ⇒ Object

Go to the next character in the line. This method doesn’t skip to the next line once the reached eol.



120
121
122
 
# File 'lib/sdl4r/parser/reader.rb', line 120

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

#skip_to(new_pos) ⇒ Object

Skips the specified position in the current line.



145
146
147
 
# File 'lib/sdl4r/parser/reader.rb', line 145

def skip_to(new_pos)
  @pos = new_pos
end

#skip_to_eol ⇒ Object

Skips the current line by going just after its end.



91
92
93
 
# File 'lib/sdl4r/parser/reader.rb', line 91

def skip_to_eol
  @pos = line_length
end

#skip_whitespaces ⇒ Object

Skips the whitespaces that follow the current position.



96
97
98
99
100
101
 
# File 'lib/sdl4r/parser/reader.rb', line 96

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).



151
152
153
 
# File 'lib/sdl4r/parser/reader.rb', line 151

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