Hello!
I’m a fresh ruby programmer from Portugal and until now I’ve been coding
mostly java programs. I’m posting here to find out what you think about
two things that annoy me in ruby:
-
The fact that variables dont have type! Sure this is andy in several
situations but it can also be a source of problems with wrong input
being passed to the methods! Because of this I’me forced to check
manually for the type in the begining of methods (ex: if
price.instance_of? Fixnum )
-
Second fact has to do with exceptions, in contrast to what happens in
java the catching of exceptions is not forced, so most times I end up
not coding the catch statement wich leads to a lot of run-time errors,
also for system functions I dont’t know wich exceptions they throw!
I would like to know your opinion about these two matters. Probably
these are not problems at all, only my java side confusing me! =D
Hope I was able to express myself correctly
On Sun, Feb 24, 2008 at 8:25 AM, Miguel F. [email protected] wrote:
price.instance_of? Fixnum )
While there may be some cases where you need to check for the class of
an object
at the beginning of methods, its generally viewed as a practice to be
avoided
unless you’ve identified a specific need for it. The capacity of Ruby
objects
to participate in operations is determined by the methods they support
(“duck typing”) not their class. For the most part, library methods
should document
what they expect and it is the responsibility of client code to
provide an object that
behaves appropriately.
- Second fact has to do with exceptions, in contrast to what happens in
java the catching of exceptions is not forced, so most times I end up
not coding the catch statement wich leads to a lot of run-time errors,
also for system functions I don’t know wich exceptions they throw!
You should be only rescuing exceptions that you can usefully do
something about. Most core methods should identify what they
raise and when in their documentation, and you can use that to
identify what you could rescue, but if you can’t reasonably
deal with an error, you shouldn’t rescue it.
On 24.02.2008 17:25, Miguel F. wrote:
I’m a fresh ruby programmer from Portugal and until now I’ve been coding
mostly java programs. I’m posting here to find out what you think about
two things that annoy me in ruby:
- The fact that variables dont have type! Sure this is andy in several
situations but it can also be a source of problems with wrong input
being passed to the methods! Because of this I’me forced to check
manually for the type in the begining of methods (ex: if
price.instance_of? Fixnum )
No, you’re not. Please read about “duck typing”. If you do not want a
dynamically typed language then clearly Ruby is not for you and you are
better served with Java. If you want to program in Ruby, you need to
adjust your mindset. You cannot expect that Ruby is just another Java
even though some things look familiar.
- Second fact has to do with exceptions, in contrast to what happens in
java the catching of exceptions is not forced, so most times I end up
not coding the catch statement wich leads to a lot of run-time errors,
also for system functions I dont’t know wich exceptions they throw!
This is only partly true: even in Java there is a ton of exceptions that
nobody forces you to catch. There has been a lot of debate about
checked vs. unchecked exceptions in general. I guess by now everything
is said about it elsewhere. 
There are pros and cons to both
approaches. IMHO unchecked exceptions fit Ruby very well while Java’s
model fits Java very well.
I would like to know your opinion about these two matters. Probably
these are not problems at all, only my java side confusing me! =D
Probably. I suggest you get accustomed to the Ruby way, revisit your
criticism after a while and see whether you still think it’s valid.
Hope I was able to express myself correctly
Absolutely. If you are interested, these topics have been discussed
excessively here so you will find plenty material in the archives.
Kind regards
robert
Miguel,
I’m a little frustrated by the dynamic typing of Ruby as well, but you
get
used to it quickly. You might rather be interested in the scala language
(http://www.scala-lang.org/) which keeps many of the useful constructs
of
ruby, but uses an even stronger typing system than java does. I’m still
new
to it, but I’m not sure it has many of the neat introspection properties
of
ruby that let you twist and bend the language.
Also check out the Eclipse ruby plugin, which I just discovered and
which
makes the lack of typing easier to work with…