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= Miscellaneous Syntax
== +alias+
The +alias+ keyword is most frequently used to alias methods. When aliasing a
method you can use either its name or a symbol:
alias new_name old_name
alias :new_name :old_name
For methods, Module#alias_method can often be used instead of +alias+.
You can also use +alias+ to alias global variables:
$old = 0
alias $new $old
p $new # prints 0
You may use +alias+ in any scope.
== +undef+
The +undef+ keyword prevents the current class from responding to calls to the
named methods.
undef my_method
You may use symbols instead of method names:
undef :my_method
You may undef multiple methods:
undef method1, method2
You may use +undef+ in any scope. See also Module#undef_method
== +BEGIN+ and +END+
+BEGIN+ defines a block that is run before any other code in the current file.
It is typically used in one-liners with <code>ruby -e</code>. Similarly +END+
defines a block that is run after any other code.
+BEGIN+ must appear at top-level and +END+ will issue a warning when you use it
inside a method.
Here is an example:
BEGIN {
count = 0
}
You must use <code>{</code> and <code>}</code> you may not use +do+ and +end+.
Here is an example one-liner that adds numbers from standard input or any files
in the argument list:
ruby -ne 'BEGIN { count = 0 }; END { puts count }; count += gets.to_i'
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