This document discusses the use of pragmas in Smalltalk as a way to annotate methods and provide additional metadata. It provides several examples of pragmas being used to mark methods for specific purposes like marking unwind methods, specifying menu items, and defining class-side configuration methods. The document suggests pragmas could potentially be used in more general ways for things like COM servers or defining preferences.

1. Pragmas:
Literal Messages as Powerful
Method Annotations
Stéphane Ducasse, Eliot Miranda and Alain Plantec
Eliot Miranda/Steve Dahl/Vassili Bykov

2. Smalltalk
has: #unary , #binary
and: #(keyword messages)
and: $A
rich: ‘literal’
syntax: 12345678 who do we appreciate
size
"Primitive. Answer the number of indexable variables in the
receiver. This value is the same as the largest legal subscript.
Essential. See Object documentation whatIsAPrimitive."
<primitive: 62>
self class isVariable ifFalse: [self errorNotIndexable].
^ 0

3. Behavior methods for creating method dictionary
addSelector: selector withMethod: compiledMethod
"Add the message selector with the corresponding compiled
method to the receiver’s method dictionary."
methodDict at: selector put:
(self validateMethod: compiledMethod forSelector: selector).
self flushVMmethodCacheEntriesFor: selector
BlockClosure class methods for private
validateMethod: compiledMethod forSelector: selector
"Intercept this so we can mark unwind method"
| method |
method := super validateMethod: compiledMethod
forSelector: selector.
^((selector == #valueOnUnwindDo: or: [selector ==
#valueNowOrOnUnwindDo:])
ifTrue: [method asUnwindMethod]
ifFalse: [method])

5. inspectUndeclared
<menuItem: ‘Inspect Undeclared’
nameKey: nil
menu: #(#menuBar #browse #inspect)
position: 15.1>
Undeclared inspect

6. inspectUndeclared
<menuItem: ‘Inspect Undeclared’
nameKey: nil
menu: #(#menuBar #browse #inspect)
position: 15.1>
Undeclared inspect
[Smalltalk hasMetaObjects]
on: MessageNotUnderstood
do: [:ex| ex message]

7. inspectUndeclared
<menuItem: ‘Inspect Undeclared’
nameKey: nil
menu: #(#menuBar #browse #inspect)
position: 15.1>
Undeclared inspect
[Smalltalk hasMetaObjects]
on: MessageNotUnderstood
do: [:ex| ex message]
Smalltalk perform: #hasMetaObjects withArguments: #()

8. inspectUndeclared
<menuItem: ‘Inspect Undeclared’
nameKey: nil
menu: #(#menuBar #browse #inspect)
position: 15.1>
Undeclared inspect
[Smalltalk hasMetaObjects]
on: MessageNotUnderstood
do: [:ex| ex message]
Smalltalk perform: #hasMetaObjects withArguments: #()
add/remove => select/collect => visit & apply => update

9. integrat|ed/ion
• subset of language
• senders/implementors browsing works
• Convenient access (Vassili)
Pragma allNamed: symbol from: subclass to: superclass

10. more generally useful
• COM server
api method pragma vs class side config
• Preferences

11. AboutVisualWorksPage class
pagePragma
<pragmas: #class>
^#(pageOrder:)
systemPragma
<pragmas: #class>
^#(systemInformation:)
ApplicationModel class
menuMethodPragmas
<pragmas: #instance>
^Menu pragmas
BlockClosure class
exceptionPragmas
<pragmas: #instance>
^#(exception:)
L
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y

12. more generally useful
• Trippy/GlamourousToolkit inspector pages
• Examples
• …?