1. Best Practices
@szarnekow

2. Anatomy of a Language
Implementation

3. Anatomy of a Language
Implementation
• Grammar

4. Anatomy of a Language
Implementation
• Grammar
• Scoping

5. Anatomy of a Language
Implementation
• Grammar
• Scoping
• Validation

6. Anatomy of a Language
Implementation
• Grammar
• Scoping
• Validation
• Execution

7. Anatomy of a Language
Implementation
• Grammar
• Scoping
• Validation
• Execution
• Editor

8. Anatomy of a Language
Implementation
• Grammar
• Scoping
• Validation
• Execution
• Editor

9. Anatomy of a Language
Implementation
le F iles
• Grammar Sa mp
• Scoping
• Validation
• Execution
• Editor

10. Anatomy of a Language
Implementation
le F iles
• Grammar Sa mp
• Scoping nit Tests
U
• Validation
• Execution
• Editor

11. Anatomy of a Language
Implementation
le F iles
• Grammar Sa mp
• Scoping nit Tests
U
edb ack
• Validation Fe
• Execution
• Editor

12. Antlr Annoyances

13. Antlr Annoyances
warning(200): Decision can match input such as "{EOF,
RULE_ID, '('}" using multiple alternatives: 1, 2
As a result, alternative(s) 2 were disabled for that input

14. Backtracking?
function funnyError() {
return 1 +
}

15. Backtracking?
function funnyError() {
return 1 +
}
mismatched input '}' expecting RULE_INT

16. Backtracking?
function funnyError() {
return 1 +
}
mismatched input '}' expecting RULE_INT

17. #1 - Grammar Tips
• Favor Syntactic Predicates over
Backtracking

18. #1 - Grammar Tips
• Favor Syntactic Predicates over
Backtracking
• Data Types Instead of Terminals

19. #1 - Grammar Tips
• Favor Syntactic Predicates over
Backtracking
• Data Types Instead of Terminals
• Use Keywords Wisely

20. Function:
! {Max} 'max' .. |
! {Min} 'min' .. |
! {Avg} 'avg' ..
;

21. Generalize It
FunctionCall:
! function=[Function] ..
;

22. Generalize It
FunctionCall:
! function=[Function] ..
;
/* Documentation */
max: (int, int):int

23. #2 - Modularity
• Concise Grammars and Library Files

24. #2 - Modularity
• Concise Grammars and Library Files
• Design For Multiple Files

25. Local / Global Scoping

26. Local / Global Scoping
• Local Scoping - Model Navigation

27. Local / Global Scoping
• Local Scoping - Model Navigation
• Scopes are Computed By Traversing
the Model

28. Local / Global Scoping
• Local Scoping - Model Navigation
• Scopes are Computed By Traversing
the Model
• Global Scoping - Index Queries

29. Local / Global Scoping
• Local Scoping - Model Navigation
• Scopes are Computed By Traversing
the Model
• Global Scoping - Index Queries
• Scope Content is Backed By Index
Data

30. #3 - Scoping
• Use the Index

31. #3 - Scoping
• Use the Index
• #getAllContents Is Not Your Friend

32. #3 - Scoping
• Use the Index
• #getAllContents Is Not Your Friend
• Loading Resources Does Not Hurt

33. #4 - Validation

34. #4 - Validation
• Loose Grammar, Loose Scoping,
Strict Validation

35. #4 - Validation
• Loose Grammar, Loose Scoping,
Strict Validation
• Specify the Location of
Errors and Warnings

36. #4 - Validation
• Loose Grammar, Loose Scoping,
Strict Validation
• Specify the Location of
Errors and Warnings
• Avoid Follow-Up Errors

37. #5 - User Interface

38. #5 - User Interface
• Filtered Content Proposals
Instead of Strict Scoping

39. #5 - User Interface
• Filtered Content Proposals
Instead of Strict Scoping
• Use Styled Strings To Prettify the UI

40. #6 - To Xbase Or
Not To Xbase

41. #6 - To Xbase Or
Not To Xbase
• DSL Used in Java Environment?

42. #6 - To Xbase Or
Not To Xbase
• DSL Used in Java Environment?
• Target Audience Developers?

43. #6 - To Xbase Or
Not To Xbase
• DSL Used in Java Environment?
• Target Audience Developers?
• Behavior and Logic?
Developers Want That!

44. #7 - Embrace Injection

45. #7 - Embrace Injection
• @Inject Is Key To Success

46. #7 - Embrace Injection
• @Inject Is Key To Success
• Avoid StandaloneSetup in Equinox

47. #7 - Embrace Injection
• @Inject Is Key To Success
• Avoid StandaloneSetup in Equinox
• ProTip: ExecutableExtensionFactory

48. #7 - Embrace Injection
• @Inject Is Key To Success
• Avoid StandaloneSetup in Equinox
• ProTip: ExecutableExtensionFactory
• e4: Don’t Confuse @Inject With @Inject

49. #7 - Embrace Injection
• @Inject Is Key To Success
• Avoid StandaloneSetup in Equinox
• ProTip: ExecutableExtensionFactory !
• e4: Don’t Confuse @Inject With @Inject

50. All Time Classics

51. All Time Classics
Measure, Don’t Guess

52. All Time Classics
Measure, Don’t Guess
Tests, Tests, Tests

53. All Time Classics
Measure, Don’t Guess
Tests, Tests, Tests
Read Code & Ask Questions

54. Thank You.