Editing Ruby (programming language) (section)

== Syntax ==
{{main|Ruby syntax}}

The syntax of Ruby is broadly similar to that of [[Perl]] and [[Python (programming language)|Python]]. Class and method definitions are signaled by keywords, whereas code blocks can be defined by either keywords or braces. In contrast to Perl, variables are not obligatorily prefixed with a [[sigil (computer programming)|sigil]]. When used, the sigil changes the semantics of scope of the variable. For practical purposes there is no distinction between [[expression (programming)|expressions]] and [[statement (programming)|statements]].<ref name="while"/><ref name="precedence"/> Line breaks are significant and taken as the end of a statement; a semicolon may be equivalently used. Unlike Python, indentation is not significant.

One of the differences from Python and Perl is that Ruby keeps all of its instance variables completely private to the class and only exposes them through accessor methods (<code>attr_writer</code>, <code>attr_reader</code>, etc.). Unlike the "getter" and "setter" methods of other languages like [[C++]] or [[Java (programming language)|Java]], accessor methods in Ruby can be created with a single line of code via [[metaprogramming]]; however, accessor methods can also be created in the traditional fashion of C++ and Java. As invocation of these methods does not require the use of parentheses, it is trivial to change an instance variable into a full function, without modifying a single line of calling code or having to do any refactoring achieving similar functionality to [[C Sharp (programming language)|C#]] and [[VB.NET]] property members.

Python's property descriptors are similar, but come with a trade-off in the development process. If one begins in Python by using a publicly exposed instance variable, and later changes the implementation to use a private instance variable exposed through a property descriptor, code internal to the class may need to be adjusted to use the private variable rather than the public property. Ruby's design forces all instance variables to be private, but also provides a simple way to declare <code>set</code> and <code>get</code> methods. This is in keeping with the idea that in Ruby, one never directly accesses the internal members of a class from outside the class; rather, one passes a message to the class and receives a response.