42.type and TypeError or 42.class and ClassError

Ara.T.Howard · Dec 17, 2003

why has #type been deprecated? i don't really like using Object#class since
it always conflicts with the keyword 'class'; eg. you have to

self.class.method

instead of the cleaner

type.method

also, having #class prefered over #type, but TypeError as the error definitely
violated POLS. we should at least have ClassError if #class is the way to go.

personally i don't see the problem with type even if it isn't _totally_ in
line with the 'ruby way' of thinking - it's meaning is perfectly clear in code
IMHO.

-a
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Jamis Buck · Dec 17, 2003

Ara.T.Howard said:
personally i don't see the problem with type even if it isn't _totally_ in
line with the 'ruby way' of thinking - it's meaning is perfectly clear in code
IMHO.

I have no idea if this is one of the reasons #type has been deprecated,
but I've always disliked it because there have been many times that I
wanted to create a method of my own, called #type. In those cases, I
either had to alias the original #type method, or simply live without it.

Yukihiro Matsumoto · Dec 17, 2003

Hi,

In message "42.type and TypeError or 42.class and ClassError"

|why has #type been deprecated?

Because type has broader meaning and tends to introduce confusion.
Besides I wanted to save the word "type" for something based on method
signature.

|also, having #class prefered over #type, but TypeError as the error definitely
|violated POLS. we should at least have ClassError if #class is the way to go.

Since type is broader concept that includes class, I think an error
caused by instances of wrong class is a part of type error.

matz.

Josef 'Jupp' SCHUGT · Dec 18, 2003

Hi!

* Ara.T.Howard; 2003-12-17, 19:21 UTC:

why has #type been deprecated?

That can be answered by quoting Gamma, Helm, Johnson Vilissides,
'Design Patterns - Elements of Reusable Object-Oriented Software',
page 16 (bottom):

It's important to understand the difference between an object's
/class/ and its /type/.

An object's class defines how the object is implemented. The
class defines the object's internal state and the implementation
of its operations. In contrast, an object's type only refers to
its interface---the set of requests to which it can respond. An
object can have many types, and objects of different classes can
have the same type.

I strongly recommend that book - it is great. It is worth its price
of 54.99 USD.

Josef 'Jupp' SCHUGT

Bermejo, Rodrigo · Dec 18, 2003

I strongly recommend that book - it is great. It is worth its price
of 54.99 USD.

Josef 'Jupp' SCHUGT

$42.50 at http://www.bookpool.com/.x/7amhiaqbd0/sm/0201633612
= ) funny ..I bought it today

Rasputin · Dec 18, 2003

* Zach Dennis said:
I feel bad for asking this question, but I am going to pull my hair out with
this. I recently got Ruby to run as a cgi under Apache2/Win2k combination.
Works great. I am now trying to do the same thing on Apache2/Redhat9 combo,
but to no avail. I keep getting the Server Error 500, premature end of
script headers.

Change to ' print "Content-type: text/html\n\n" '

print "<html><body>Hello</body></html>"

I was having this problem on my windows box at first but then I changed the
first line to read:
#! ruby
and it has worked ever since. However I have changed the first line on my
test.rb file on the Linux box to the following variations:
#! ruby
#!/usr/local/bin/ruby
#!/bin/ruby
#!/bin/env ruby
#! /bin/env ruby

Run 'which ruby' in a shell and set the path in the shebang line
(the #! line above to whatever you get back).

Josef 'Jupp' SCHUGT · Dec 18, 2003

Hi!

* Bermejo, Rodrigo:

$42.50 at http://www.bookpool.com/.x/7amhiaqbd0/sm/0201633612

54.99 USD is what is printed on the cover. Actually I didn't pay that
price, either.

Well, perhaps that is really of interest for Germans: Lehmanns
- http://wwww.lob.de/ - is running a 20% off campaign for a couple of
great English language books.

Josef 'Jupp' SCHUGT

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42.type and TypeError or 42.class and ClassError

Ara.T.Howard

Jamis Buck

Yukihiro Matsumoto

Josef 'Jupp' SCHUGT

Bermejo, Rodrigo

Rasputin

Josef 'Jupp' SCHUGT

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