Add some comments for Pry::Code::LOC

Signed-off-by: Kyrylo Silin <kyrylosilin@gmail.com>

lib/pry/code.rb

@@ -26,9 +26,29 @@ def Code(obj)
   # arbitrary chaining of formatting methods without mutating the original
   # object.
   class Code
+    # Represents a line of code. A line of code is a tuple, which consists of a
+    # line and a line number. A `LOC` object's state (namely, the line
+    # parameter) can be changed via instance methods. `Pry::Code` heavily uses
+    # this class.
+    #
+    # @api private
+    # @example
+    #   loc = LOC.new("def example\n  :example\nend", 1)
+    #   puts loc.line
+    #   def example
+    #     :example
+    #   end
+    #   #=> nil
+    #
+    #   loc.indent(3)
+    #   loc.line #=> "   def example\n  :example\nend"
     class LOC
+
+      # @return [Array<String, Integer>]
       attr_accessor :tuple
 
+      # @param [String] line The line of code.
+      # @param [Integer] lineno The position of the +line+.
       def initialize(line, lineno)
         @tuple = [line.chomp, lineno.to_i]
       end
@@ -37,18 +57,28 @@ def dup
         self.class.new(line, lineno)
       end
 
+      # @return [String]
       def line
         tuple.first
       end
 
+      # @return [Integer]
       def lineno
         tuple.last
       end
 
+      # Paints the `line` of code.
+      #
+      # @param [Symbol] code_type
+      # @return [void]
       def colorize(code_type)
         tuple[0] = CodeRay.scan(line, code_type).term
       end
 
+      # Prepends the line number `lineno` to the `line`.
+      #
+      # @param [Integer] max_width
+      # @return [void]
       def add_line_numbers(max_width = 0)
         padded = lineno.to_s.rjust(max_width)
         colorized_lineno = Pry::Helpers::BaseHelpers.colorize_code(padded)
@@ -64,6 +94,10 @@ def add_marker(marker_lineno)
           end
       end
 
+      # Indents the `line` with +distance+ spaces.
+      #
+      # @param [Integer] distance
+      # @return [void]
       def indent(distance)
         tuple[0] = "#{ ' ' * distance }#{ line }"
       end