1 files changed, 72 insertions, 1 deletions
diff --git a/activesupport/lib/active_support/core_ext/string/access.rb b/activesupport/lib/active_support/core_ext/string/access.rb
index 9b5266c58c..5c32a2453d 100644
--- a/activesupport/lib/active_support/core_ext/string/access.rb
+++ b/activesupport/lib/active_support/core_ext/string/access.rb
@@ -1,18 +1,79 @@
-require "active_support/multibyte"
+require 'active_support/multibyte'
 
 class String
+  # If you pass a single Fixnum, returns a substring of one character at that
+  # position. The first character of the string is at position 0, the next at
+  # position 1, and so on. If a range is supplied, a substring containing
+  # characters at offsets given by the range is returned. In both cases, if an
+  # offset is negative, it is counted from the end of the string. Returns nil
+  # if the initial offset falls outside the string. Returns an empty string if
+  # the beginning of the range is greater than the end of the string.
+  #
+  #   str = "hello"
+  #   str.at(0)      #=> "h"
+  #   str.at(1..3)   #=> "ell"
+  #   str.at(-2)     #=> "l"
+  #   str.at(-2..-1) #=> "lo"
+  #   str.at(5)      #=> nil
+  #   str.at(5..-1)  #=> ""
+  #
+  # If a Regexp is given, the matching portion of the string is returned.
+  # If a String is given, that given string is returned if it occurs in
+  # the string. In both cases, nil is returned if there is no match.
+  #
+  #   str = "hello"
+  #   str.at(/lo/) #=> "lo"
+  #   str.at(/ol/) #=> nil
+  #   str.at("lo") #=> "lo"
+  #   str.at("ol") #=> nil
   def at(position)
     self[position]
   end
 
+  # Returns a substring from the given position to the end of the string.
+  # If the position is negative, it is counted from the end of the string.
+  #
+  #   str = "hello"
+  #   str.from(0)  #=> "hello"
+  #   str.from(3)  #=> "lo"
+  #   str.from(-2) #=> "lo"
+  #
+  # You can mix it with +to+ method and do fun things like:
+  #
+  #   str = "hello"
+  #   str.from(0).to(-1) #=> "hello"
+  #   str.from(1).to(-2) #=> "ell"
   def from(position)
     self[position..-1]
   end
 
+  # Returns a substring from the beginning of the string to the given position.
+  # If the position is negative, it is counted from the end of the string.
+  #
+  #   str = "hello"
+  #   str.to(0)  #=> "h"
+  #   str.to(3)  #=> "hell"
+  #   str.to(-2) #=> "hell"
+  #
+  # You can mix it with +from+ method and do fun things like:
+  #
+  #   str = "hello"
+  #   str.from(0).to(-1) #=> "hello"
+  #   str.from(1).to(-2) #=> "ell"
   def to(position)
     self[0..position]
   end
 
+  # Returns the first character. If a limit is supplied, returns a substring
+  # from the beginning of the string until it reaches the limit value. If the
+  # given limit is greater than or equal to the string length, returns self.
+  #
+  #   str = "hello"
+  #   str.first    #=> "h"
+  #   str.first(1) #=> "h"
+  #   str.first(2) #=> "he"
+  #   str.first(0) #=> ""
+  #   str.first(6) #=> "hello"
   def first(limit = 1)
     if limit == 0
       ''
@@ -23,6 +84,16 @@ class String
     end
   end
 
+  # Returns the last character of the string. If a limit is supplied, returns a substring
+  # from the end of the string until it reaches the limit value (counting backwards). If
+  # the given limit is greater than or equal to the string length, returns self.
+  #
+  #   str = "hello"
+  #   str.last    #=> "o"
+  #   str.last(1) #=> "o"
+  #   str.last(2) #=> "lo"
+  #   str.last(0) #=> ""
+  #   str.last(6) #=> "hello"
   def last(limit = 1)
     if limit == 0
       ''