CODEWITHSUNDEEP
smalltalksqueakglobal-variables
Renne
Renne

Reputation:

How to create a global variable in Squeak?

I don't mean a class variable. I want a variable that can be used everywhere. Where should I define it? [in squeak]

Upvotes: 4

Views: 2728

Answers (3)

Nat
Nat

Reputation: 9951

Squeak stores all class instances and other global variables in the SystemDictionary called "Smalltalk". You can define a global variable like this:

Smalltalk at: #variableName put: theValue.

Refering to the variable variableName will return theValue.

However, good Smalltalk style is to avoid global variables altogether.

Upvotes: 6

Janko Mivšek
Janko Mivšek

Reputation: 3964

One way is to make a singleton, as in this answer.

In general you make a class variable and accompanying class method to let some object become a globally accessible. See above mentioned singleton as an example. Such variable is then accesses from elsewhere:

global := MyClass myGlobalVar

To became also globally changeable, make mutator class method and call it like:

MyClass myGlobalVar: true

There are other ways too, but this one with class variables is portable around Smalltalk dialects, long term it is therefore the most safe way.

Upvotes: 4

Norbert Hartl
Norbert Hartl

Reputation: 10851

Well a class in smalltalk is globally available und you can change it whenever you like. Just create a class and add your altering code as class methods. You can then access your stuff by calling

MyVariable thisOrThat
MyVariable updateThisOrThat: aThisOrThat

Upvotes: 1

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