class String - Documentation for Ruby 2.2.0

class String BigDecimal extends the native String class to provide the to_d method. When you require BigDecimal in your application, this method will be available on String objects. additions to class String for Unicode normalization A String object holds and manipulates an arbitrary sequence of bytes, typically representing characters. String objects may be created using String::new or as literal

[tmsanrinsha]

“Return the Integer ordinal of a one-character string.”