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* doc/syntax/miscellaneous.rdoc: Added documentation for alias, undef,

BEGIN, END.
* doc/syntax/modules_and_classes.rdoc (Constants):  Fixed unwrapped
  paragraph with trailing whitespace.
* doc/syntax/modules_and_classes.rdoc (Scope):  Added section pointing
  to alias and undef documentation.
* doc/syntax.rdoc:  Added link to miscellaneous section.


git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@38853 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
This commit is contained in:
drbrain 2013-01-16 23:36:46 +00:00
parent 038c535e18
commit 1eb9f71c3a
4 changed files with 83 additions and 2 deletions

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@ -1,3 +1,13 @@
Thu Jan 17 08:36:04 2013 Eric Hodel <drbrain@segment7.net>
* doc/syntax/miscellaneous.rdoc: Added documentation for alias, undef,
BEGIN, END.
* doc/syntax/modules_and_classes.rdoc (Constants): Fixed unwrapped
paragraph with trailing whitespace.
* doc/syntax/modules_and_classes.rdoc (Scope): Added section pointing
to alias and undef documentation.
* doc/syntax.rdoc: Added link to miscellaneous section.
Thu Jan 17 07:50:26 2013 Eric Hodel <drbrain@segment7.net>
* doc/syntax/control_expressions.rdoc (Flip-Flop): Added a section on

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@ -23,3 +23,6 @@ Exceptions[rdoc-ref:syntax/exceptions.rdoc] ::
Precedence[rdoc-ref:syntax/precedence.rdoc] ::
Precedence of ruby operators
Miscellaneous[rdoc-ref:syntax/miscellaneous.rdoc] ::
+alias+, +undef+, +BEGIN+, +END+

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@ -0,0 +1,61 @@
= 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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@ -93,8 +93,9 @@ nesting:
end
end
However, if you use <code>::</code> to define <code>A::B</code> without nesting
it inside +A+ a NameError exception will be raised because the nesting does not include +A+:
However, if you use <code>::</code> to define <code>A::B</code> without
nesting it inside +A+ a NameError exception will be raised because the nesting
does not include +A+:
module A
Z = 1
@ -193,6 +194,12 @@ The third visibility is +private+. A private method may not be called with a
receiver, not even +self+. If a private method is called with a receiver a
NoMethodError will be raised.
=== +alias+ and +undef+
You may also alias or undefine methods, but these operations are not
restricted to modules or classes. See the {miscellaneous syntax
section}[rdoc-ref:syntax/miscellaneous.rdoc] for documentation.
= Classes
Every class is also a module, but unlike modules a class may not be mixed-in to