Asp Forum - gem and uninitialized constant

John Franey

4/6/2007 1:44:00 AM

I want to use NetAddr 1.2 with gems 0.9.2 and ruby 1.8.5 on Suse 10.2.
The lines of code:

require 'rubygems'
gem 'netaddr'
ipadd = NetAddr::CIDR.create("192.9.200.0/24")

The error: uninitialized constant NetAddr (NameError)

This works:

require 'rubygems'
require_gem 'netaddr'
ipadd = NetAddr::CIDR.create("192.9.200.0/24")

But I get the warning: "require_gem is obsolete. Use gem instead."

Any comments?

Thanks

6 Answers

Brian Candler

4/6/2007 6:06:00 AM

On Fri, Apr 06, 2007 at 10:44:00AM +0900, John Franey wrote:
> I want to use NetAddr 1.2 with gems 0.9.2 and ruby 1.8.5 on Suse 10.2.
> The lines of code:
>
> require 'rubygems'
> gem 'netaddr'
> ipadd = NetAddr::CIDR.create("192.9.200.0/24")
>
> The error: uninitialized constant NetAddr (NameError)
>
>
> This works:
>
> require 'rubygems'
> require_gem 'netaddr'
> ipadd = NetAddr::CIDR.create("192.9.200.0/24")
>
> But I get the warning: "require_gem is obsolete. Use gem instead."

Have you tried:

require 'rubygems'
require 'netaddr'

?
(Newer versions of rubygems replace 'require' directly)

John Franey

4/6/2007 5:50:00 PM

Brian,

Thanks for responding:

This code:

require 'rubygems'
require 'netaddr'
ipadd = NetAddr::CIDR.create("192.9.200.0/24")

gives:

/usr/lib/ruby/site_ruby/1.8/rubygems/custom_require.rb:27:in
`gem_original_require': no such file to load -- netaddr (LoadError)
from /usr/lib/ruby/site_ruby/1.8/rubygems/custom_require.rb:27:in
`require'
from ci.rb:2

This code:

require 'rubygems'
require 'net_addr'
ipadd = NetAddr::CIDR.create("192.9.200.0/24")

works.

Now, how am I supposed to learn the right string to put into the require
call. The command to install was:

gem install netaddr

I don't remember why I guessed 'net_addr'

John

Brian Candler wrote:
>
> On Fri, Apr 06, 2007 at 10:44:00AM +0900, John Franey wrote:
>> I want to use NetAddr 1.2 with gems 0.9.2 and ruby 1.8.5 on Suse 10.2.
>> The lines of code:
>>
>> require 'rubygems'
>> gem 'netaddr'
>> ipadd = NetAddr::CIDR.create("192.9.200.0/24")
>>
>> The error: uninitialized constant NetAddr (NameError)
>>
>>
>> This works:
>>
>> require 'rubygems'
>> require_gem 'netaddr'
>> ipadd = NetAddr::CIDR.create("192.9.200.0/24")
>>
>> But I get the warning: "require_gem is obsolete. Use gem instead."
>
> Have you tried:
>
> require 'rubygems'
> require 'netaddr'
>
> ?
> (Newer versions of rubygems replace 'require' directly)
>
>
>

--
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Phillip Gawlowski

4/6/2007 6:50:00 PM

John J. Franey wrote:
> Brian,
>
> Thanks for responding:
>
> This code:
>
> require 'rubygems'
> require 'netaddr'
> ipadd = NetAddr::CIDR.create("192.9.200.0/24")
>
> gives:
>
> /usr/lib/ruby/site_ruby/1.8/rubygems/custom_require.rb:27:in
> `gem_original_require': no such file to load -- netaddr (LoadError)
> from /usr/lib/ruby/site_ruby/1.8/rubygems/custom_require.rb:27:in
> `require'
> from ci.rb:2
>
> This code:
>
> require 'rubygems'
> require 'net_addr'
> ipadd = NetAddr::CIDR.create("192.9.200.0/24")
>
> works.
>
> Now, how am I supposed to learn the right string to put into the require
> call. The command to install was:
>
> gem install netaddr

If the gem generates documentation, I'd look there. Otherwise, look into
your /usr/lib/ruby/gems/1.8/name_of_gem directories for a README or code
code examples. In case you didn't know it gem_server launches a small
server, which makes the RDoc documentation accessible (in case the
developer was smart enough to include such a thing ;)

Otherwise, you might take your chances and even look at the gem's
homepage. in this case, it probably is http://netaddr.rub...

P.S.:
A: Because it makes reading replies difficult.
Q: Why is top-posting bad?

--
Phillip "CynicalRyan" Gawlowski
http://cynicalryan....

Rule of Open-Source Programming #1:

Don't whine unless you are going to implement it yourself.

Bernard Kenik

4/7/2007 5:16:00 AM

On Apr 6, 2:50 pm, Phillip Gawlowski <cmdjackr...@googlemail.com>
wrote:
> John J. Franey wrote:
> > Brian,
>
> > Thanks for responding:
>
> > This code:
>
> > require 'rubygems'
> > require 'netaddr'
> > ipadd = NetAddr::CIDR.create("192.9.200.0/24")
>
> > gives:
>
> > /usr/lib/ruby/site_ruby/1.8/rubygems/custom_require.rb:27:in
> > `gem_original_require': no such file to load -- netaddr (LoadError)
> > from /usr/lib/ruby/site_ruby/1.8/rubygems/custom_require.rb:27:in
> > `require'
> > from ci.rb:2
>
> > This code:
>
> > require 'rubygems'
> > require 'net_addr'
> > ipadd = NetAddr::CIDR.create("192.9.200.0/24")
>
> > works.
>
> > Now, how am I supposed to learn the right string to put into the require
> > call. The command to install was:
>
> > gem install netaddr
>
> If the gem generates documentation, I'd look there. Otherwise, look into
> your /usr/lib/ruby/gems/1.8/name_of_gem directories for a README or code
> code examples. In case you didn't know it gem_server launches a small
> server, which makes the RDoc documentation accessible (in case the
> developer was smart enough to include such a thing ;)
>
> Otherwise, you might take your chances and even look at the gem's
> homepage. in this case, it probably ishttp://netaddr.rub...
>
> P.S.:
> A: Because it makes reading replies difficult.
> Q: Why is top-posting bad?
>
> --
> Phillip "CynicalRyan" Gawlowskihttp://cynicalryan....
>
> Rule of Open-Source Programming #1:
>
> Don't whine unless you are going to implement it yourself.- Hide quoted text -
>
> - Show quoted text -

I got caught in the same puzzle that the OP got trapped.

A gem has a name "gemname" which is used to install --- gem install
gemname
A "require" loads the gem and needs to know the gem's base
filename .. which is the filename without an extension.
Usually (probably 99% of time), the gemname and the base filename are
the same although it is not a requirement.
A gem filename may have "rb" as an extension but it could also have
"so" as an extension ... 'require' is smart enough to look
for valid extensions.

As CynicalRyan stated, you have to dig into the documentation and hope
to find the information.

In the case of the netaddr gem, the example in the documentation is
outdated. Only by looking at the list of netaddr's files would you
have seen "net_addr.rb"

Brian Candler

4/7/2007 9:30:00 AM

On Sat, Apr 07, 2007 at 02:49:54AM +0900, John J. Franey wrote:
> This code:
>
> require 'rubygems'
> require 'net_addr'
> ipadd = NetAddr::CIDR.create("192.9.200.0/24")
>
> works.
>
> Now, how am I supposed to learn the right string to put into the require
> call.

I'd just do
ls -lR /usr/lib/ruby/gems/1.8/gems/netaddr*

John Franey

4/7/2007 3:44:00 PM

bbiker wrote:
>
> On Apr 6, 2:50 pm, Phillip Gawlowski <cmdjackr...@googlemail.com>
> wrote:
>> John J. Franey wrote:
>
>> > This code:
>>
>> > require 'rubygems'
>> > require 'netaddr'
>
> fails:
>> > `gem_original_require': no such file to load -- netaddr (LoadError)
>> > from
>> /usr/lib/ruby/site_ruby/1.8/rubygems/custom_require.rb:27:in`require'
>
>> > This code:
>>
>> > require 'rubygems'
>> > require 'net_addr'
> doesn't
>
>>
>> > Now, how am I supposed to learn the right string to put into the
>> require
>> > call. The command to install was:
>>
>> > gem install netaddr
>>
>> If the gem generates documentation, I'd look there. Otherwise, look into
>> your /usr/lib/ruby/gems/1.8/name_of_gem directories for a README or code
>> code examples. In case you didn't know it gem_server launches a small
>> server, which makes the RDoc documentation accessible (in case the
>> developer was smart enough to include such a thing ;)
>>
>> Otherwise, you might take your chances and even look at the gem's
>> homepage. in this case, it probably ishttp://netaddr.rub...
>>
>>
>> --
>> Phillip "CynicalRyan" Gawlowskihttp://cynicalryan....
>>
>
>
> I got caught in the same puzzle that the OP got trapped.
>
> A gem has a name "gemname" which is used to install --- gem install
> gemname
> A "require" loads the gem and needs to know the gem's base
> filename .. which is the filename without an extension.
> Usually (probably 99% of time), the gemname and the base filename are
> the same although it is not a requirement.
> A gem filename may have "rb" as an extension but it could also have
> "so" as an extension ... 'require' is smart enough to look
> for valid extensions.
>
> As CynicalRyan stated, you have to dig into the documentation and hope
> to find the information.
>
> In the case of the netaddr gem, the example in the documentation is
> outdated. Only by looking at the list of netaddr's files would you
> have seen "net_addr.rb"
>
>
>
>
>

I got good responses to this question thanks. Basically, the answer is
"dig". I can do and did in this case. Digging won't be the best way after
someone has already solved the problem with a command, which is what I was
fishing for. Thanks for you help and understanding.

John

--
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Sent from the ruby-talk mailing list archive at Nabble.com.

comp.lang.ruby

gem and uninitialized constant

John Franey

Brian Candler

John Franey

Phillip Gawlowski

Bernard Kenik

Brian Candler

John Franey

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