13.3: Browsing the System

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Page ID: 39242

Andrew P. Black, Stéphane Ducasse, Oscar Nierstrasz, Damien Pollet

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FAQ \(\PageIndex{1}\)

The browser does not look like the one described in the book. What gives?

Answer

You are probably using an image in which the OmniBrowser is installed as the default System browser. You can change the default by clicking on the little menu icon in the top-left corner of the browser window, between the “X” and the browser label, and selecting “Choose new default browser” from the menu that appears. Select #Browser to get the plain old browser. (This preference changes the effect of the World ⊳ open . . . ⊳ system browser menu, but not what happens when you drag the Browser icon from the Tools flap.)

FAQ \(\PageIndex{2}\)

How do I search for a class?

Answer

CMD–b (browse) on the class name, or CMD–f in the category pane of the class browser.

FAQ \(\PageIndex{3}\)

How do I find/browse all sends to super?

Answer

The second solution is much faster:

SystemNavigation default browseMethodsWithSourceString: 'super'.
SystemNavigation default browseAllSelect: [:method | method sendsToSuper ].

FAQ \(\PageIndex{4}\)

How do I browse all super sends within a hierarchy?

Answer

browseSuperSends := [:aClass | SystemNavigation default
    browseMessageList: (aClass withAllSubclasses gather: [ :each |
        (each methodDict associations
            select: [ :assoc | assoc value sendsToSuper ])
                collect: [ :assoc | MethodReference class: each selector: assoc key ] ])
    name: 'Supersends of ' , aClass name , ' and its subclasses'].
browseSuperSends value: OrderedCollection.

FAQ \(\PageIndex{5}\)

How do I find out which new methods are introduced by a class? (I.e., not including overridden methods.)

Answer

Here we ask which methods are introduced by True:

newMethods := [:aClass| aClass methodDict keys select:
    [:aMethod | (aClass superclass canUnderstand: aMethod) not ]].
newMethods value: True −→ an IdentitySet(#asBit)

FAQ \(\PageIndex{6}\)

How do I tell which methods of a class are abstract?

Answer

abstractMethods :=
    [:aClass | aClass methodDict keys select:
        [:aMethod | (aClass>>aMethod) isAbstract ]].
abstractMethods value: Collection −→ an IdentitySet(#remove:ifAbsent: #add:
    #do:)

FAQ \(\PageIndex{7}\)

How do I generate a view of the AST of an expression?

Answer

Load AST from squeaksource.com. Then evaluate:

(RBParser parseExpression: '3+4') explore

(Alternatively explore it.)

FAQ \(\PageIndex{8}\)

How do I find all the Traits in the system?

Answer

Smalltalk allTraits

FAQ \(\PageIndex{9}\)

How do I find which classes use traits?

Answer

Smalltalk allClasses select: [:each | each hasTraitComposition and: [each
    traitComposition notEmpty ]]