ESUG 2011, Edinburgh

1. PHANtom:
A Modern Aspect Language for Pharo
Johan Fabry, Daniel Galdames. PLEIAD Lab, DCC - Universidad de Chile

2. AOP ??
Johan Fabry 2

3. AOP ??
Cross-cutting concerns
Aspect = module
‣ Behavior = WHAT = advice
‣ Quantification = WHEN = pointcuts
Running application = stream of join points
‣ ST computation = messages
‣ In PHANtom: method exec
Johan Fabry 2

4. AOP ??
Cross-cutting concerns
Aspect = module
‣ Behavior = WHAT = advice
‣ Quantification = WHEN = pointcuts
Running application = stream of join points
‣ ST computation = messages
‣ In PHANtom: method exec
Johan Fabry 2

5. AOP ??
Cross-cutting concerns
Aspect = module
‣ Behavior = WHAT = advice
‣ Quantification = WHEN = pointcuts
Running application = stream of join points
‣ ST computation = messages
‣ In PHANtom: method exec
Johan Fabry 2

6. AOP ??
Cross-cutting concerns
Aspect = module
‣ Behavior = WHAT = advice
‣ Quantification = WHEN = pointcuts
Running application = stream of join points
‣ ST computation = messages
‣ In PHANtom: method exec
Johan Fabry 2

7. AOP ??
Cross-cutting concerns
Aspect = module
‣ Behavior = WHAT = advice
‣ Quantification = WHEN = pointcuts
Running application = stream of join points
‣ ST computation = messages
‣ In PHANtom: method exec
Johan Fabry 2

8. In the spirit of Smalltalk
Dynamic
Simple Powerful
Johan Fabry 3

9. In the spirit of Smalltalk
Dynamic
Dynamic AOP
Simple Powerful
Johan Fabry 3

10. In the spirit of Smalltalk
Dynamic
Dynamic AOP Develop normally
Simple Powerful
Johan Fabry 3

11. In the spirit of Smalltalk
Dynamic
Dynamic AOP Develop normally
Simple Powerful
Minimal set of Constructs
Johan Fabry 3

12. In the spirit of Smalltalk
Dynamic
Dynamic AOP Develop normally
Simple Powerful
Minimal set of Constructs
Uniform / no restrictions
Johan Fabry 3

13. In the spirit of Smalltalk
Dynamic
Dynamic AOP Develop normally
Simple Powerful
Minimal set of Constructs First-class everything
Uniform / no restrictions
Johan Fabry 3

14. In the spirit of Smalltalk
Dynamic
Dynamic AOP Develop normally
Simple Powerful
Minimal set of Constructs First-class everything
Uniform / no restrictions New language features
Johan Fabry 3

15. Pointcuts
Dyn
Sim Pow
Johan Fabry 4

16. Pointcuts
PhPointcut receivers: 'TestCase'
selectors: 'assert:'
Dyn
Sim Pow
Johan Fabry 4

17. Pointcuts
PhPointcut receivers: 'TestCase'
selectors: 'assert:'
PhPointcut receivers: 'TestCase+'
selectors: #(assert: assert:equals:)
Dyn
Sim Pow
Johan Fabry 4

18. Pointcuts
PhPointcut receivers: 'TestCase'
selectors: 'assert:'
PhPointcut receivers: 'TestCase+'
selectors: #(assert: assert:equals:)
context: #(receiver sender arguments)
Dyn
Sim Pow
Johan Fabry 4

19. Pointcuts
PhPointcut receivers: 'TestCase'
selectors: 'assert:'
PhPointcut receivers: 'TestCase+'
selectors: #(assert: assert:equals:)
context: #(receiver sender arguments)
PhPointcut receivers: 'Test*'
selectors: #(assert: assert:_:
assert:_:_:)
Dyn
context: #(receiver)
restrict: #(Tests_Mine)
Sim Pow
Johan Fabry 4

20. Advice
Dyn
Sim Pow
Johan Fabry 5

21. Advice
PhAdvice pointcut: pc
send: #incCount: to: self
type: #after
Dyn
Sim Pow
Johan Fabry 5

22. Advice
PhAdvice pointcut: pc
send: #incCount: to: self
type: #after
PhAdvice pointcut: pc
advice: [:ctx |
Transcript show:
(ctx receiver asString);cr.
ctx proceed.]] Dyn
type: #around.
Sim Pow
Johan Fabry 5

23. Inter-Type Declaration
Dyn
Sim Pow
Johan Fabry 6

24. Inter-Type Declaration
PhClassModifier on: ACTestCase
addIV: 'phacount'
Dyn
Sim Pow
Johan Fabry 6

25. Inter-Type Declaration
PhClassModifier on: ACTestCase
addIV: 'phacount'
PhClassModifier on: ACTestCase
addIM: 'phacount
↑phacount ifNil: [phacount := 0]'
Dyn
Sim Pow
Johan Fabry 6

26. Aspect
PHAspect subclass: MyAspect ...
(Object subclass: #PhAspect ...)
Add PHAdvice and PHClassModifier instances
Send install to activate
Send uninstall to deactivate Dyn
Sim Pow
Johan Fabry 7

27. What happens here?
|asp|
asp := PhAspect new add:
(PhAdvice
pointcut: (PhPointcut
receivers: 'Transcript class'
selectors: 'show:')
advice: [ Transcript show: 'Have ']
type: #before).
asp install.
Transcript show: 'reentrancy control'; cr
Johan Fabry 8

28. What happens here?
|asp|
asp := PhAspect new add:
(PhAdvice
pointcut: (PhPointcut
receivers: 'Transcript class'
selectors: 'show:')
advice: [ Transcript show: 'Have ']
type: #before).
asp install.
Transcript show: 'reentrancy control'; cr
Johan Fabry 8

29. What happens here?
|asp|
asp := PhAspect new add:
(PhAdvice
pointcut: (PhPointcut
receivers: 'Transcript class'
selectors: 'show:')
advice: [ Transcript show: 'Have ']
type: #before).
asp install.
Transcript show: 'reentrancy control'; cr
Johan Fabry 8

30. What happens here?
|asp|
asp := PhAspect new add:
(PhAdvice
pointcut: (PhPointcut
receivers: 'Transcript class'
selectors: 'show:')
advice: [ Transcript show: 'Have ']
type: #before).
asp install.
Transcript show: 'reentrancy control'; cr
Johan Fabry 8

31. What happens here?
|asp|
asp := PhAspect new add:
(PhAdvice
pointcut: (PhPointcut
receivers: 'Transcript class'
selectors: 'show:')
advice: [ Transcript show: 'Have ']
type: #before).
asp install.
Transcript show: 'reentrancy control'; cr
Johan Fabry 8

32. What happens here?
|asp|
asp := PhAspect new add:
(PhAdvice
pointcut: (PhPointcut
receivers: 'Transcript class'
selectors: 'show:')
advice: [ Transcript show: 'Have ']
type: #before).
asp install.
Transcript show: 'reentrancy control'; cr
Johan Fabry 8

33. What happens here?
|asp|
asp := PhAspect new add:
(PhAdvice
pointcut: (PhPointcut
receivers: 'Transcript class'
selectors: 'show:')
advice: [ Transcript show: 'Have ']
type: #before).
asp install.
Transcript show: 'reentrancy control'; cr
Johan Fabry 8

34. What happens here?
|asp|
OM
asp := PhAspect new add:
(PhAdvice
pointcut: (PhPointcut
receivers: 'Transcript class'
selectors: 'show:')
advice: [ Transcript show: 'Have ']
type: #before).
BO
asp install.
Transcript show: 'reentrancy control'; cr
Johan Fabry 8

35. Reentrancy control
PHANtom: no problem!
‣ Aspect execution by default NOT MATCHED
More power if you want it: Membranes [Tanter & Tabareau]
Use membranes to control
‣ join point emission and capture scope
‣ aspect observing join points Dyn
Sim Pow
Johan Fabry 9

36. Advice ordering
Multiple advice 1 join point
“Classic”: advice precedence
‣ Global and static
PHANtom deployment precedence
‣ Global and ‘static’
‣ Complement or override on pointcut
PHANtom dynamic precedence in the advice
‣ OrderedCollection of PHAdvice instances
‣ get from context Dyn
‣ set on context
Sim Pow
Johan Fabry 10

37. Not in the paper ...
TDD
‣ 155 tests
‣ 90+% coverage
Johan Fabry 11

38. Not in the paper ...
TDD
‣ 155 tests
‣ 90+% coverage
Johan Fabry 11

39. Future work
Optimize the implementation
Compile PHANtom code
Infrastructure for Domain-Specific Aspect Languages
Johan Fabry 12

40. http://pleiad.cl/PHANtom
Johan Fabry 13