As domain-specific modeling begins to attract widespread acceptance, pressure is increasing for the development of new domain-specific languages. Unfortunately these DSLs typically conflict with the grammar of the host language, making it difficult to compose hybrid code except at the level of strings; few mechanisms (if any) exist to control the scope of usage of multiple DSLs; and, most seriously, existing host language tools are typically unaware of the DSL extensions, thus hampering the development process. Language boxes address these issues by offering a simple, modular mechanism to encapsulate (i) compositional changes to the host language, (ii) transformations to address various concerns such as compilation and syntax highlighting, and (iii) scoping rules to control visibility of fine-grained language extensions. We describe the design and implementation of language boxes, and show with the help of several examples how modular extensions can be introduced to a host language and environment.

1. Language Boxes
Bending the Host Language
with Modular Language Changes
Lukas Renggli, Marcus Denker, Oscar Nierstrasz

2. Marco Zanoli, cc-by-sa, 2.5, www.wikipedia.de, 2006

3. Marco Zanoli, cc-by-sa, 2.5, www.wikipedia.de, 2006

4. Marco Zanoli, cc-by-sa, 2.5, www.wikipedia.de, 2006

5. §
§
§
Marco Zanoli, cc-by-sa, 2.5, www.wikipedia.de, 2006

6. Marco Zanoli, cc-by-sa, 2.5, www.wikipedia.de, 2006

7. Marco Zanoli, cc-by-sa, 2.5, www.wikipedia.de, 2006

8. Marco Zanoli, cc-by-sa, 2.5, www.wikipedia.de, 2006

9. §
§
§
Marco Zanoli, cc-by-sa, 2.5, www.wikipedia.de, 2006

11. Host Environment

12. Tool Infrastructure
Host Environment

13. Syntax
Language 1
Editor
Compiler
Language 2
Debugger

14. Syntax
Language 1
Editor
Compiler
Language 2
Debugger

15. Syntax
Language 1
Editor
Compiler
Language 2
Debugger

16. Syntax
Language 1
Editor
Compiler
Language 2
Debugger

17. Marco Zanoli, cc-by-sa, 2.5, www.wikipedia.de, 2006

18. Tool Infrastructure
Host Environment

19. Language Boxes
Tool Infrastructure
Host Environment

20. Language Box
Model

21. Language
*
Change
Language * Language
Box Concern
*
* Language
Scope

22. IV + VII = XI

23. Language
*
Change
Language * Language
Box Concern
*
* Language
Scope

24. Language Change
Insert FRAGMENT
(before|after) PRODUCTION
as (choice|sequence|replacement)

25. Language Change
Insert RomanNumber
before NumberLiteral
as a choice.

26. Language Change
Literal: BooleanLiteral
NilLiteral
NumberLiteral
StringLiteral
ArrayLiteral
NumberLiteral: IntegerLiteral
FloatLiteral

27. Language Change
RomanNumber: 'I' .. 'M'

28. Language Change
Literal: BooleanLiteral
NilLiteral
NumberLiteral'
StringLiteral
ArrayLiteral
NumberLiteral': RomanNumber
NumberLiteral

29. Language Change
1st Class Grammar
Scannerless, Packrat

30. Language Concern
Production Action

31. Language Concern
Compiler
aToken value romanToArabic lift

32. Language Concern
Highlighting
aToken -> Color gray

33. Language Concern
Custom Actions

34. Language Scope
Active?

35. Language Scope
System

36. Language Scope
Packages

37. Language Scope
Classes

38. Language Scope
Methods

39. Language
*
Change
Language * Language
Box Concern
*
* Language
Scope

40. Conflicts

41. Language Language Language Language
Box 1 Box 2 Box 3 Box 4

42. Language Language Language Language
Box 1 Box 2 Box 3 Box 4

43. Language Language Language Language
Box 1 Box 2 Box 3 Box 4

44. Language Language Language Language
Box 1 Box 2 Box 3 Box 4
ostGrammar

45. Language Language Language Language
Box 1 Box 2 Box 3 Box 4
HostGrammar

46. Language Language Language Language
Box 1 Box 2 Box 3 Box 4
HostGramm

47. Language Language Language Language
Box 1 Box 2 Box 3 Box 4

49. HostGrammar'

50. con sis t
mi gh t rts
us e d pa
o f un
HostGrammar'

51. con sis t m igh t b
mi gh t rts am big u e
us e d pa o us
o f un
HostGrammar'

52. PackratParser
HostGrammar'

53. SELECT * FROM users

54. <SQL: SELECT * FROM users>

55. Marco Zanoli, cc-by-sa, 2.5, www.wikipedia.de, 2006

56. scg.unibe.ch/research/helvetia