# Change of Symbol to respond to intern? **URL:** \ **Category:** Ruby\ **Created:** [August 14, 2007, 5:32pm UTC](https://www.ruby-forum.com/t/change-of-symbol-to-respond-to-intern/112047 "2007-08-14T17:32:29Z")\ **Posts on this page:** 7\ **Page:** 1
**Author:** ![unknown](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/u/4bbf92/32.png) [@unknown](https://www.ruby-forum.com/u/unknown)\ **Post date:** [August 14, 2007, 5:32pm UTC](https://www.ruby-forum.com/t/change-of-symbol-to-respond-to-intern/112047/1 "2007-08-14T17:32:29Z")
I often find myself writing methods with the following form: def foo(sym\_or\_str) @iv = sym\_or\_str end when I go to compare later vs @iv, I can do: def compare\_vs\_iv(arg) if arg.to\_s == @iv.to\_s then … end … end but I can’t do: if arg.intern == @iv.intern then … end This is because symbols don’t respond to intern. Is there any good reason Symbol doesn’t respond to intern, while String responds to to\_s, Array responds, to to\_a, etc.? If not, I would like to propose that the intern method be added to Symbol at some point. Thoughts? ---
**Author:** ![unknown](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/u/4bbf92/32.png) [@unknown](https://www.ruby-forum.com/u/unknown)\ **Post date:** [August 14, 2007, 5:52pm UTC](https://www.ruby-forum.com/t/change-of-symbol-to-respond-to-intern/112047/2 "2007-08-14T17:52:31Z")
On 8/14/07, removed\_email\_address@domain.invalid [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) wrote: > if arg.to\_s == @iv.to\_s then > > This is because symbols don’t respond to intern. Is there any good > reason Symbol doesn’t respond to intern, while String responds to > to\_s, Array responds, to to\_a, etc.? If not, I would like to propose > that the intern method be added to Symbol at some point. > > Thoughts? Not sure of the differences (if any) between #intern and #to\_sym, but symbols will respond to #to\_sym and just return self. If there aren’t any differences between #intern and #to\_sym, I’d agree, #intern should be added to Symbol. Chris ---
**Author:** ![unknown](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/u/4bbf92/32.png) [@unknown](https://www.ruby-forum.com/u/unknown)\ **Post date:** [August 14, 2007, 6:51pm UTC](https://www.ruby-forum.com/t/change-of-symbol-to-respond-to-intern/112047/3 "2007-08-14T18:51:38Z")
> Thoughts? irb(main):005:0\> :FOO.to\_sym =\> :FOO irb(main):006:0\> “FOO”.to\_sym =\> :FOO Or you can always do something like class Symbol def intern self end end ---
**Author:** ![unknown](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/u/4bbf92/32.png) [@unknown](https://www.ruby-forum.com/u/unknown)\ **Post date:** [August 14, 2007, 7:18pm UTC](https://www.ruby-forum.com/t/change-of-symbol-to-respond-to-intern/112047/4 "2007-08-14T19:18:17Z")
unknown wrote: > This is because symbols don’t respond to intern. Is there any good > reason Symbol doesn’t respond to intern, while String responds to > to\_s, Array responds, to to\_a, etc.? If not, I would like to propose > that the intern method be added to Symbol at some point. irb(main):001:0\> class Symbol; alias\_method :intern, :to\_sym; end =\> Symbol irb(main):002:0\> :symbol.intern =\> :symbol ---
**Author:** ![unknown](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/u/4bbf92/32.png) [@unknown](https://www.ruby-forum.com/u/unknown)\ **Post date:** [August 14, 2007, 7:16pm UTC](https://www.ruby-forum.com/t/change-of-symbol-to-respond-to-intern/112047/5 "2007-08-14T19:16:42Z")
On Aug 14, 11:26 am, removed\_email\_address@domain.invalid wrote: > This is because symbols don’t respond to intern. Is there any good > reason Symbol doesn’t respond to intern, while String responds to > to\_s, Array responds, to to\_a, etc.? If not, I would like to propose > that the intern method be added to Symbol at some point. Symbol responds to #to\_sym, as does String. Will that do? ---
**Author:** ![unknown](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/u/4bbf92/32.png) [@unknown](https://www.ruby-forum.com/u/unknown)\ **Post date:** [August 15, 2007, 6:37pm UTC](https://www.ruby-forum.com/t/change-of-symbol-to-respond-to-intern/112047/6 "2007-08-15T18:37:11Z")
- [removed\_email\_address@domain.invalid](mailto:removed_email_address@domain.invalid) (22:00) schrieb: > I knew about overloading Symbol, but I think we can all agree that’s > not really a practical solution for use in a bigger system. I didn’t > know about to\_sym though, and I think that’s perfect! Shows what I > get for thinking that I knew the core API pretty well… But probably want to do the to\_s anyway, because that doesn’t pollute the symbol table. Strings can be garbage collected, symbols stay for ever. mfg, simon … l ---
**Author:** ![unknown](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/u/4bbf92/32.png) [@unknown](https://www.ruby-forum.com/u/unknown)\ **Post date:** [August 14, 2007, 10:06pm UTC](https://www.ruby-forum.com/t/change-of-symbol-to-respond-to-intern/112047/7 "2007-08-14T22:06:03Z")
On Aug 14, 11:26 am, removed\_email\_address@domain.invalid wrote: > ``` > ... > > ``` > > This is because symbols don’t respond to intern. Is there any good > reason Symbol doesn’t respond to intern, while String responds to > to\_s, Array responds, to to\_a, etc.? If not, I would like to propose > that the intern method be added to Symbol at some point. > > Thoughts? I knew about overloading Symbol, but I think we can all agree that’s not really a practical solution for use in a bigger system. I didn’t know about to\_sym though, and I think that’s perfect! Shows what I get for thinking that I knew the core API pretty well… Thanks… --Tom