[Newbies] Undeclared variable issue
Roel.Wuyts at ulb.ac.be
Wed Sep 6 08:38:20 UTC 2006
| n |
n := 5 factorial.
Some more explanation: -> is a binary message sent to a receiver
object to create an association (an instance of class Association
that is basically a key/value pair). For example, inspect the result
of the following expression in a workspace:
3 -> 4
In your original piece of code, when you do n -> 5, variable n is
indeed undefined, and if you proceed it will create an association
between the 'nil' object (yes, it is a real object as well) and 5.
If you want, you can look up the implementation of the selector ->,
for example by using the Selector Browser in your tools flab (the one
at the right), and you will then find that there is a method -> on
class Object with the following implementation:
"Answer an Association between self and anObject"
^Association basicNew key: self value: anObject
On 05 Sep 2006, at 20:17, Edward A. Waugh wrote:
> The following code doesn't execute in my Squeak workspace
> | n |
> n <- 5 factorial.
> n printString
> because it insists that n is undeclared despite that I have declare
> the it in the first line of the 3 line code fragment. (I highlight
> all 3 lines and use the "do it" to execute it.)
> What is going here - this is valid Smalltalk syntax?
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