[Newbies] Newbie: Error Checking in Dynamically typed Language

[stephane ducasse]

Hi

normally you will not do explicit check.
We only test when this is really important.

> Hi all,
> This is my first time working with a dynamically typed environment  
> and my first instinct is to error check all arguments.

No good instinct for dynamically typed :)

> For example suppose I want to create an object to represent an  
> octet in an IP address (a number between 0 and 256) I would do  
> something like this:
>
> Object subclass: #Octet
>    instanceVariables: 'octetValue'
>    ......
>
> initialize
>    super initialize.
>    octetValue := 0.
>
> setOctetValue: numBtw0And256
>    octetValue = numBtw0And256        <-------Here's where I have a  
> problem
>
> How do I know the numBtw0And256 is actually an integer between 0  
> and 256 and not 'cat' or '3.14'?
>
> Since I came from statically typed languages I feel like I writing  
> a whole bunch of error  checking code along the lines of  
> ifIsInteger: ... etc which doesn't seem to be in the spirit of Squeak.
>
> What am I doing wrong?

Just write your code and tests!
Initialize well your state.
Do only check if you absolutely want in your constructor?

>
> Thanks
>
> Deech
>
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