# How to aliase a module method? **URL:** \ **Category:** Ruby\ **Created:** [March 8, 2007, 11:35am UTC](https://www.ruby-forum.com/t/how-to-aliase-a-module-method/88123 "2007-03-08T11:35:29Z")\ **Posts on this page:** 7\ **Page:** 1
**Author:** ![fxn](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/f/77aa72/32.png) [@fxn](https://www.ruby-forum.com/u/fxn)\ **Post date:** [March 8, 2007, 11:35am UTC](https://www.ruby-forum.com/t/how-to-aliase-a-module-method/88123/1 "2007-03-08T11:35:29Z")
I am trying to aliase a module method to some local alias (to ease some template). I’ve tried a few variations of alias escape\_latex MyUtils.escape\_latex without luck so far. I could mixin the module or write a wrapper, but I’d like to know how to accomplish that with alias, or that it is not possible if that’s the case. – fxn ---
**Author:** ![fxn](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/f/77aa72/32.png) [@fxn](https://www.ruby-forum.com/u/fxn)\ **Post date:** [March 9, 2007, 12:10am UTC](https://www.ruby-forum.com/t/how-to-aliase-a-module-method/88123/2 "2007-03-09T00:10:30Z")
On Mar 8, 5:34 am, Xavier N. [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) wrote: > I am trying to aliase a module method to some local alias (to ease > some template). I’ve tried a few variations of > > alias escape\_latex MyUtils.escape\_latex > > without luck so far. I could mixin the module or write a wrapper, but > I’d like to know how to accomplish that with alias, or that it is not > possible if that’s the case. It’s possible, sort of. Try module TheModule instance\_eval “alias escape\_latex MyUtils.escape\_latex” end I use a similar technique (originally suggested by Minero A., according to my notes) to replace Thread.critical and Thread.critical=. I’ve only tested it in 1.8.2 but I don’t think anything’s broken it since then. ---
**Author:** ![fxn](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/f/77aa72/32.png) [@fxn](https://www.ruby-forum.com/u/fxn)\ **Post date:** [March 9, 2007, 12:16am UTC](https://www.ruby-forum.com/t/how-to-aliase-a-module-method/88123/3 "2007-03-09T00:16:30Z")
On Fri, 9 Mar 2007 removed\_email\_address@domain.invalid wrote: > It’s possible, sort of. Try > > > – fxn > > module M > > class \<\< self > > alias\_method ‘dst’, ‘src’ > > end > > end -a ---
**Author:** ![fxn](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/f/77aa72/32.png) [@fxn](https://www.ruby-forum.com/u/fxn)\ **Post date:** [March 9, 2007, 12:18am UTC](https://www.ruby-forum.com/t/how-to-aliase-a-module-method/88123/4 "2007-03-09T00:18:31Z")
On 3/8/07, Xavier N. [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) wrote: > I am trying to aliase a module method to some local alias (to ease > some template). I’ve tried a few variations of > > alias escape\_latex MyUtils.escape\_latex > > without luck so far. I could mixin the module or write a wrapper, but > I’d like to know how to accomplish that with alias, or that it is not > possible if that’s the case. first of all, you need to use symbols for methods (actually, you just refer to the names of the methods): alias :escape\_latex :MyUtils.escape\_latex Can you see the problem: how you’d write the symbol for MyUtils.escape\_latex? This is not the way. Now, this is excerpt from Ryan D.’ Ruby QuickRef ([Ruby | zenspider.com | by ryan davis](http://www.zenspider.com/Languages/Ruby/QuickRef.html)): Aliasing alias :new :old alias\_method :new, :old Creates a new reference to whatever old referred to. old can be any existing method, operator, global. It may not be a local, instance, constant, or class variable. The simple solution would be in this case (provided you don’t mind including the other methods of the module): include MyUtils PS: I’ve tried module TheModule instance\_eval “alias escape\_latex MyUtils.escape\_latex” end and I got: (eval):1: parse error, unexpected ‘.’, expecting $ alias escape\_latex MyUtils.escape\_latex ^(pointing at the dot) I don’t think it’d work, but I may be wrong, and will be glad if somebody will show the working code for this. ---
**Author:** ![fxn](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/f/77aa72/32.png) [@fxn](https://www.ruby-forum.com/u/fxn)\ **Post date:** [March 9, 2007, 3:04am UTC](https://www.ruby-forum.com/t/how-to-aliase-a-module-method/88123/5 "2007-03-09T03:04:48Z")
On Mar 9, 2007, at 12:17 AM, Jan S. wrote: > first of all, you need to use symbols for methods (actually, you just > refer to the names of the methods): No, that’s not true. – fxn ---
**Author:** ![fxn](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/f/77aa72/32.png) [@fxn](https://www.ruby-forum.com/u/fxn)\ **Post date:** [March 9, 2007, 5:20pm UTC](https://www.ruby-forum.com/t/how-to-aliase-a-module-method/88123/6 "2007-03-09T17:20:52Z")
On 3/8/07, Xavier N. [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) wrote: > > > possible if that’s the case. > > > anything’s broken it since then. > > > alias foo Math.sqrt > > > Because alias requires that both arguments be names (or symbols), Note > > > that it’s not a method but is directly performed by the ruby > > > interpreter. irb(main):001:0\> alias foo Math.sqrt SyntaxError: compile error (irb):1: parse error, unexpected ‘.’, expecting $ alias foo Math.sqrt ^ from (irb):1 You’re not even getting to eval.c, it’s failing to parse. Module#alias\_method requires that it’s aruments be symbols cooresponding to the name. The other problem is that you are trying to make a name in a different scope than the name you are aliasing. As far as I can see this isn’t possible. – Rick DeNatale My blog on Ruby [http://talklikeaduck.denhaven2.com/](http://talklikeaduck.denhaven2.com/) ---
**Author:** ![fxn](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/f/77aa72/32.png) [@fxn](https://www.ruby-forum.com/u/fxn)\ **Post date:** [March 9, 2007, 3:33am UTC](https://www.ruby-forum.com/t/how-to-aliase-a-module-method/88123/7 "2007-03-09T03:33:51Z")
On Mar 9, 2007, at 12:10 AM, removed\_email\_address@domain.invalid wrote: > It’s possible, sort of. Try > > module TheModule > instance\_eval “alias escape\_latex MyUtils.escape\_latex” > end > > I use a similar technique (originally suggested by Minero A., > according to my notes) to replace Thread.critical and > Thread.critical=. I’ve only tested it in 1.8.2 but I don’t think > anything’s broken it since then. I don’t understand that technique (it is not working here). In fact what I don’t understand is alias. In irb we can do alias foo sprintf Why can’t we say alias foo Math.sqrt ? Having a quick glance at eval.c I think the problem is that alias is syntax (that’s why it does not need a comma between its “arguments”) and I guess here’s the key: case NODE\_ALIAS: if (NIL\_P(ruby\_class)) { rb\_raise(rb\_eTypeError, “no class to make alias”); } rb\_alias(ruby\_class, rb\_to\_id(rb\_eval(self, node-\>u1.node)), rb\_to\_id(rb\_eval(self, node-\>u2.node))); – fxn