# How to get the list of all classes?
**URL:** https://rubytalk.org/t/how-to-get-the-list-of-all-classes/7850
**Category:** ruby-talk
**Created:** [4 September 2003 19:36 UTC](https://rubytalk.org/t/how-to-get-the-list-of-all-classes/7850 "2003-09-04T19:36:26Z")
**Posts on this page:** 11
**Page:** 1
### Author:  [@Tobi\_Reif](https://rubytalk.org/u/Tobi_Reif)
#### Post date: [4 September 2003 19:36 UTC](https://rubytalk.org/t/how-to-get-the-list-of-all-classes/7850/1 "2003-09-04T19:36:26Z")
Hi
I’m writing a syntax highlighting program [code] for Ruby code listings
in XML (eg DocBook) documents.
To get the global variables I do
puts Kernel.global\_variables
and to get the names of some common methods I do
puts methods
and
puts Kernel.methods
.
How to get the names of all classes? (all built-in classes or all available)
I need to get “File”, “Hash”, etc.
Any other wordlist-returning snippets are welcome too.
TIA,
Tobi
[code]
XSLT:
[http://www.pinkjuice.com/howto/vimxml/xslt/tinydbk2xhtml/markup\_ruby.xslt](http://www.pinkjuice.com/howto/vimxml/xslt/tinydbk2xhtml/markup_ruby.xslt)
sample:
[http://www.pinkjuice.com/howto/vimxml/setup.xml#jing](http://www.pinkjuice.com/howto/vimxml/setup.xml#jing)
(scroll down)
> **···**
>
> –
> [http://www.pinkjuice.com/](http://www.pinkjuice.com/)
---
### Author:  [@Wesley\_J\_Landaker](https://rubytalk.org/u/Wesley_J_Landaker)
#### Post date: [4 September 2003 19:41 UTC](https://rubytalk.org/t/how-to-get-the-list-of-all-classes/7850/2 "2003-09-04T19:41:13Z")
Apparently, Tobias Reif recently wrote:
> Hi
>
> I’m writing a syntax highlighting program [code] for Ruby code listings
> in XML (eg DocBook) documents.
>
> To get the global variables I do
> puts Kernel.global\_variables
> and to get the names of some common methods I do
> puts methods
> and
> puts Kernel.methods
> .
>
> How to get the names of all classes? (all built-in classes or all
> available)
> I need to get “File”, “Hash”, etc.
Here is one way:
$ ruby -e ‘x = ; ObjectSpace.each\_object { |o| x \<\< o if o.class ==
Class }; p x’
[UnboundMethod, Method, Binding, Proc, SystemStackError, LocalJumpError,
Struct::Tms, Process::Status, Time, Dir, File::Stat, File, IO, EOFError,
IOError, Range, MatchData, Regexp, RegexpError, Struct, Hash, Array,
Bignum, Float, Fixnum, Integer, Numeric, FloatDomainError,
ZeroDivisionError, ThreadGroup, Continuation, Thread, ThreadError,
Errno::EDQUOT, Errno::EREMOTEIO, Errno::EISNAM, Errno::ENAVAIL,
Errno::ENOTNAM, Errno::EUCLEAN, Errno::ESTALE, Errno::EINPROGRESS,
Errno::EALREADY, Errno::EHOSTUNREACH, Errno::EHOSTDOWN,
Errno::ECONNREFUSED, Errno::ETIMEDOUT, Errno::ETOOMANYREFS,
Errno::ESHUTDOWN, Errno::ENOTCONN, Errno::EISCONN, Errno::ENOBUFS,
Errno::ECONNRESET, Errno::ECONNABORTED, Errno::ENETRESET,
Errno::ENETUNREACH, Errno::ENETDOWN, Errno::EADDRNOTAVAIL,
Errno::EADDRINUSE, Errno::EAFNOSUPPORT, Errno::EPFNOSUPPORT,
Errno::EOPNOTSUPP, Errno::ESOCKTNOSUPPORT, Errno::EPROTONOSUPPORT,
Errno::ENOPROTOOPT, Errno::EPROTOTYPE, Errno::EMSGSIZE,
Errno::EDESTADDRREQ, Errno::ENOTSOCK, Errno::EUSERS, Errno::ESTRPIPE,
Errno::ERESTART, Errno::EILSEQ, Errno::ELIBEXEC, Errno::ELIBMAX,
Errno::ELIBSCN, Errno::ELIBBAD, Errno::ELIBACC, Errno::EREMCHG,
Errno::EBADFD, Errno::ENOTUNIQ, Errno::EOVERFLOW, Errno::EBADMSG,
Errno::EDOTDOT, Errno::EMULTIHOP, Errno::EPROTO, Errno::ECOMM,
Errno::ESRMNT, Errno::EADV, Errno::ENOLINK, Errno::EREMOTE, Errno::ENOPKG,
Errno::ENONET, Errno::ENOSR, Errno::ETIME, Errno::ENODATA, Errno::ENOSTR,
Errno::EBFONT, Errno::EBADSLT, Errno::EBADRQC, Errno::ENOANO,
Errno::EXFULL, Errno::EBADR, Errno::EBADE, Errno::EL2HLT, Errno::ENOCSI,
Errno::EUNATCH, Errno::ELNRNG, Errno::EL3RST, Errno::EL3HLT,
Errno::EL2NSYNC, Errno::ECHRNG, Errno::EIDRM, Errno::ENOMSG, Errno::ELOOP,
Errno::ENOTEMPTY, Errno::ENOSYS, Errno::ENOLCK, Errno::ENAMETOOLONG,
Errno::EDEADLK, Errno::ERANGE, Errno::EDOM, Errno::EPIPE, Errno::EMLINK,
Errno::EROFS, Errno::ESPIPE, Errno::ENOSPC, Errno::EFBIG, Errno::ETXTBSY,
Errno::ENOTTY, Errno::EMFILE, Errno::ENFILE, Errno::EINVAL, Errno::EISDIR,
Errno::ENOTDIR, Errno::ENODEV, Errno::EXDEV, Errno::EEXIST, Errno::EBUSY,
Errno::ENOTBLK, Errno::EFAULT, Errno::EACCES, Errno::ENOMEM,
Errno::EAGAIN, Errno::ECHILD, Errno::EBADF, Errno::ENOEXEC, Errno::E2BIG,
Errno::ENXIO, Errno::EIO, Errno::EINTR, Errno::ESRCH, Errno::ENOENT,
Errno::EPERM, SystemCallError, NoMemoryError, SecurityError, RuntimeError,
NotImplementedError, LoadError, SyntaxError, ScriptError, NoMethodError,
NameError, RangeError, IndexError, ArgumentError, TypeError,
StandardError, Interrupt, SignalException, fatal, SystemExit, Exception,
String, FalseClass, TrueClass, Data, Symbol, NilClass, Class, Module,
Object]
---
### Author:  [@Tobi\_Reif](https://rubytalk.org/u/Tobi_Reif)
#### Post date: [5 September 2003 21:39 UTC](https://rubytalk.org/t/how-to-get-the-list-of-all-classes/7850/3 "2003-09-05T21:39:11Z")
How to get the list of names which includes “print”?
TIA,
Tobi
I wrote:
> I’m writing a syntax highlighting program [code] for Ruby code
> listings in XML (eg DocBook) documents.
> […]
> **···**
>
> > Any other wordlist-returning snippets are welcome too.
>
> –
> [http://www.pinkjuice.com/](http://www.pinkjuice.com/)
---
### Author:  [@Ryan\_Pavlik](https://rubytalk.org/u/Ryan_Pavlik)
#### Post date: [4 September 2003 20:01 UTC](https://rubytalk.org/t/how-to-get-the-list-of-all-classes/7850/4 "2003-09-04T20:01:50Z")
\> Here is one way: \> \> $ ruby -e 'x = []; ObjectSpace.each\_object { |o| x \< Class }; p x'
This is probably quicker if you do:
```
x = []
ObjectSpace.each_object(Class) { |c| x << c }
```
…so you don’t have to iterate through thousands of non-Class objects.
> **···**
>
> On Fri, 5 Sep 2003 04:41:13 +0900 “Wesley J. Landaker” [wjl@icecavern.net](mailto:wjl@icecavern.net) wrote:
>
> –
> Ryan Pavlik [rpav@mephle.com](mailto:rpav@mephle.com)
>
> “So… I’m not a total bad-ass fueled by relentless evil?” - 8BT
---
### Author:  [@Tobi\_Reif](https://rubytalk.org/u/Tobi_Reif)
#### Post date: [5 September 2003 21:43 UTC](https://rubytalk.org/t/how-to-get-the-list-of-all-classes/7850/5 "2003-09-05T21:43:11Z")
Sorry, please ignore the previous post.
(forgot to look in Kernel.methods)
Tobi
> How to get the list of names which includes “print”?
> […]
> **···**
>
> –
> [http://www.pinkjuice.com/](http://www.pinkjuice.com/)
---
### Author:  [@Mark\_J\_Reed](https://rubytalk.org/u/Mark_J_Reed)
#### Post date: [4 September 2003 20:46 UTC](https://rubytalk.org/t/how-to-get-the-list-of-all-classes/7850/6 "2003-09-04T20:46:51Z")
It seems odd to me that ObjectSpace doesn’t mixin Enumerable, but
that’s easily remedied:
```
module ObjectSpace
class << self
include Enumerable
def each(*args, &block) each_object(*args, &block) end
end
end
```
Then you can just do this:
```
ObjectSpace.find_all { |c| c.class == Class }
```
Although it is still, as noted above, probably less efficient than
passing Class to each\_object. But it’s an aesthetic improvement,
I think. I mean, the idea of having to iterate over
a collection with a block that does nothing but an array append, just
to get the collection into array form, seems very backwards to me.
-Mark
> **···**
>
> On Fri, Sep 05, 2003 at 05:01:50AM +0900, Ryan Pavlik wrote:
>
> > > $ ruby -e ‘x = ; ObjectSpace.each\_object { |o| x \<\< o if o.class ==
> > > Class }; p x’
> >
> > This is probably quicker if you do:
> >
> > ```
> > x = []
> > ObjectSpace.each_object(Class) { |c| x << c }
> >
> > ```
> >
> > …so you don’t have to iterate through thousands of non-Class objects.
---
### Author:  [@Wesley\_J\_Landaker](https://rubytalk.org/u/Wesley_J_Landaker)
#### Post date: [4 September 2003 20:57 UTC](https://rubytalk.org/t/how-to-get-the-list-of-all-classes/7850/7 "2003-09-04T20:57:50Z")
Apparently, Mark J. Reed recently wrote:
> **···**
>
> > On Fri, Sep 05, 2003 at 05:01:50AM +0900, Ryan Pavlik wrote:
> >
> > > > $ ruby -e ‘x = ; ObjectSpace.each\_object { |o| x \<\< o if o.class ==
> > > > Class }; p x’
> > >
> > > This is probably quicker if you do:
> > >
> > > ```
> > > x = []
> > > ObjectSpace.each_object(Class) { |c| x << c }
> > >
> > > ```
> > >
> > > …so you don’t have to iterate through thousands of non-Class objects.
> >
> > It seems odd to me that ObjectSpace doesn’t mixin Enumerable, but
> > that’s easily remedied:
> >
> > module ObjectSpace
> > class \<\< self
> > include Enumerable
> > def each(\*args, &block) each\_object(\*args, &block) end
> > end
> > end
> >
> > Then you can just do this:
> >
> > ObjectSpace.find\_all { |c| c.class == Class }
> >
> > Although it is still, as noted above, probably less efficient than
> > passing Class to each\_object. But it’s an aesthetic improvement,
> > I think. I mean, the idea of having to iterate over
> > a collection with a block that does nothing but an array append, just
> > to get the collection into array form, seems very backwards to me.
>
> I agree that having ObjectSpace enumerable would make sense. Actually, the
> first thing I tried when I saw the original message was:
>
> ObjectSpace.select { |x| x.class == Class }
>
> … but then I realized that it wasn’t Enumerable.
>
> Wes
>
> Wes
---
### Author:  [@Jason\_Creighton3](https://rubytalk.org/u/Jason_Creighton3)
#### Post date: [5 September 2003 04:28 UTC](https://rubytalk.org/t/how-to-get-the-list-of-all-classes/7850/8 "2003-09-05T04:28:49Z")
> > > $ ruby -e ‘x = ; ObjectSpace.each\_object { |o| x \<\< o if o.class ==
> > > Class }; p x’
> >
> > This is probably quicker if you do:
> >
> > ```
> > x = []
> > ObjectSpace.each_object(Class) { |c| x << c }
> >
> > ```
> >
> > …so you don’t have to iterate through thousands of non-Class objects.
>
> It seems odd to me that ObjectSpace doesn’t mixin Enumerable, but
> that’s easily remedied:
Yes, that’s seemed odd to me at times as well.
> module ObjectSpace
> class \<\< self
> include Enumerable
> def each(\*args, &block) each\_object(\*args, &block) end
> end
> end
err…why don’t you just alias each to each\_object?
module ObjectSpace
class \<\< self
include Enumerable
alias :each :each\_object
end
end
No mess, no fuss, no greasy aftertaste.
> Then you can just do this:
>
> ObjectSpace.find\_all { |c| c.class == Class }
>
> Although it is still, as noted above, probably less efficient than
> passing Class to each\_object. But it’s an aesthetic improvement,
> I think. I mean, the idea of having to iterate over
> a collection with a block that does nothing but an array append, just
> to get the collection into array form, seems very backwards to me.
It only seems backwards if you’re used to Ruby. 🙂
Jason Creighton
> **···**
>
> On Thu, 04 Sep 2003 20:37:32 GMT “Mark J. Reed” [markjreed@mail.com](mailto:markjreed@mail.com) wrote:
>
> > On Fri, Sep 05, 2003 at 05:01:50AM +0900, Ryan Pavlik wrote:
---
### Author:  [@Mark\_J\_Reed](https://rubytalk.org/u/Mark_J_Reed)
#### Post date: [5 September 2003 13:09 UTC](https://rubytalk.org/t/how-to-get-the-list-of-all-classes/7850/9 "2003-09-05T13:09:45Z")
MJR = me
JC = Jason Creighton
> module ObjectSpace
> class \<\< self
> include Enumerable
> def each(\*args, &block) each\_object(\*args, &block) end
> end
> end
> err…why don’t you just alias each to each\_object?
> module ObjectSpace
> class \<\< self
> include Enumerable
> alias :each :each\_object
> end
> end
Uhm . . . because it’s too easy?
I wanted to show off my understanding of passing &blocks around?
Maybe I’m a firm believer in TMTOWTDI?
Would you believe . . . I just forgot about alias? 🙂
Thanks.
-Mark
---
### Author:  [@David\_A\_Black2](https://rubytalk.org/u/David_A_Black2)
#### Post date: [5 September 2003 13:32 UTC](https://rubytalk.org/t/how-to-get-the-list-of-all-classes/7850/10 "2003-09-05T13:32:45Z")
Hi –
> > ```
> > module ObjectSpace
> > class << self
> > include Enumerable
> > def each(*args, &block) each_object(*args, &block) end
> > end
> > end
> >
> > ```
>
> err…why don’t you just alias each to each\_object?
>
> module ObjectSpace
> class \<\< self
> include Enumerable
> alias :each :each\_object
> end
> end
Or even:
class \<\< ObjectSpace
include Enumerable
alias :each :each\_object
end
Or, wandering into arguably too-compressed territory:
class \<\< ObjectSpace.extend(Enumerable)
alias :each :each\_object
end
David
> **···**
>
> On Fri, 5 Sep 2003, Jason Creighton wrote:
>
> > On Thu, 04 Sep 2003 20:37:32 GMT \> “Mark J. Reed” [markjreed@mail.com](mailto:markjreed@mail.com) wrote:
>
> –
> David Alan Black
> home: [dblack@superlink.net](mailto:dblack@superlink.net)
> work: blackdav@shu.edu
> Web: [http://pirate.shu.edu/~blackdav](http://pirate.shu.edu/~blackdav)
---
### Author:  [@Thomas\_Adam2](https://rubytalk.org/u/Thomas_Adam2)
#### Post date: [5 September 2003 13:19 UTC](https://rubytalk.org/t/how-to-get-the-list-of-all-classes/7850/11 "2003-09-05T13:19:10Z")
— “Mark J. Reed” [markjreed@mail.com](mailto:markjreed@mail.com) wrote: \> MJR = me
> JC = Jason Creighton
>
> > ```
> > module ObjectSpace
> > class << self
> > include Enumerable
> > def each(*args, &block) each_object(*args, &block) end
> > end
> > end
> >
> > ```
>
> > err…why don’t you just alias each to each\_object?
>
> > module ObjectSpace
> > class \<\< self
> > include Enumerable
> > alias :each :each\_object
> > end
> > end
>
> Uhm . . . because it’s too easy?
I agree with Jason here, alias is the way to go, it even speeds it up on
my machine, odd as it seems.
> I wanted to show off my understanding of passing &blocks around?
> Maybe I’m a firm believer in TMTOWTDI?
TMTOWTDI is a perl idiom 🙂
> Would you believe . . . I just forgot about alias? 🙂
It happens 🙂 I have aliases too: people call me “percy” from time to
time, depending on who’s asking 🙂
– Thomas Adam
> **···**
>
> =====
> Thomas Adam
>
> “The Linux Weekend Mechanic” – [www.linuxgazette.com](http://www.linuxgazette.com)
>
> * * *
>
> Want to chat instantly with your online friends? Get the FREE Yahoo!
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