Eolian, our language independent API description language and library, has gone through a lot of development during the past year. There were several significant design aspects that had to be resolved and some are still remaining. In this talk I will summarize my experiences developing Eolian recently as well as the future plans.

1. Eolian - Past year experiences and
the future
Shaping up our binding generation infrastructure
Daniel Kolesa
Samsung Open Source Group
d.kolesa@osg.samsung.com
@octaforge
EFL Developer Day 2015

2. Introduction
For those living under a rock

3. What is Eolian?

4. What is Eolian?
Most people are probably already aware of it

5. What is Eolian?
Most people are probably already aware of it
It’s several things

6. What is Eolian?
Most people are probably already aware of it
It’s several things
It’s a declarative format for describing APIs

7. What is Eolian?
Most people are probably already aware of it
It’s several things
It’s a declarative format for describing APIs
It’s a C library to deal with these declarations

8. What is Eolian?
Most people are probably already aware of it
It’s several things
It’s a declarative format for describing APIs
It’s a C library to deal with these declarations
It’s a generator for the core C API

9. Why is Eolian useful?

10. Why is Eolian useful?
Language independent API descriptions

11. Why is Eolian useful?
Language independent API descriptions
Automatic generation of bindings for any language

12. Why is Eolian useful?
Language independent API descriptions
Automatic generation of bindings for any language
Improved documentation possibilities

13. Why is Eolian useful?
Language independent API descriptions
Automatic generation of bindings for any language
Improved documentation possibilities
Better tooling

14. Why is Eolian useful?
Language independent API descriptions
Automatic generation of bindings for any language
Improved documentation possibilities
Better tooling
The possibilities are endless

15. Past and present
How was Eolian and how is it now?

16. Last year Eolian

17. How was it?

18. How was it?
Very basic

19. How was it?
Very basic
Supported C generation and nothing else

20. How was it?
Very basic
Supported C generation and nothing else
A messy parser/lexer created with a generator

21. How was it?
Very basic
Supported C generation and nothing else
A messy parser/lexer created with a generator
A lot of design problems

22. How did we fix it?

23. How did we fix it?
First project: write a new parser from scratch

24. How did we fix it?
First project: write a new parser from scratch
Gradual rewrite of Eolian from ground up

25. How did we fix it?
First project: write a new parser from scratch
Gradual rewrite of Eolian from ground up
Fixed design problems one by one

26. How did we fix it?
First project: write a new parser from scratch
Gradual rewrite of Eolian from ground up
Fixed design problems one by one
Through iterative approach, we got where we are currently

27. Main challenges of last year and the
present

28. Eolian type system

29. Eolian type system
Old Eolian used C strings to do types

30. Eolian type system
Old Eolian used C strings to do types
No verification

31. Eolian type system
Old Eolian used C strings to do types
No verification
Not suitable for other languages

32. Eolian type system
Old Eolian used C strings to do types
No verification
Not suitable for other languages
We needed our own type system

34. Real types represented in our in-memory database

35. Real types represented in our in-memory database
Basic type checking/verification (usage contexts etc.)

36. Real types represented in our in-memory database
Basic type checking/verification (usage contexts etc.)
Integration with variables/constants

37. Real types represented in our in-memory database
Basic type checking/verification (usage contexts etc.)
Integration with variables/constants
Structures and enumerations

38. Real types represented in our in-memory database
Basic type checking/verification (usage contexts etc.)
Integration with variables/constants
Structures and enumerations
Type aliases

39. Real types represented in our in-memory database
Basic type checking/verification (usage contexts etc.)
Integration with variables/constants
Structures and enumerations
Type aliases
Extern types and other smaller features

40. Custom constructors

41. Custom constructors
Old Eolian supported custom constructors for classes

42. Custom constructors
Old Eolian supported custom constructors for classes
We decided this is a bad idea

43. Custom constructors
Old Eolian supported custom constructors for classes
We decided this is a bad idea
We generate constructors using constructing functions now

44. Syntax revision

45. Syntax revision
Old syntax was very messy and inconsistent

46. Syntax revision
Old syntax was very messy and inconsistent
Complete refactoring of syntax was done

47. Syntax revision
Old syntax was very messy and inconsistent
Complete refactoring of syntax was done
Unification and stricter parsing

48. Syntax revision
Old syntax was very messy and inconsistent
Complete refactoring of syntax was done
Unification and stricter parsing
Focus on consistency

49. Complex types

50. Complex types
At first, we had generalized complex types

51. Complex types
At first, we had generalized complex types
This proved to be a bad idea

52. Complex types
At first, we had generalized complex types
This proved to be a bad idea
Provided several built-in complex types (array, hash etc.)

53. Complex types
At first, we had generalized complex types
This proved to be a bad idea
Provided several built-in complex types (array, hash etc.)
Greatly simplfied generation and syntax

54. Data sharing

55. Data sharing
We needed to share typedefs etc. between several classes

56. Data sharing
We needed to share typedefs etc. between several classes
Introduced .eot (eo type) files

57. Data sharing
We needed to share typedefs etc. between several classes
Introduced .eot (eo type) files
And introduced an import statement

58. Documentation

59. Documentation
Ongoing issue

60. Documentation
Ongoing issue
Doxygen will no longer cut it (specific to C/C++)

61. Documentation
Ongoing issue
Doxygen will no longer cut it (specific to C/C++)
Designed a custom format

62. Documentation
Ongoing issue
Doxygen will no longer cut it (specific to C/C++)
Designed a custom format
Removed documentation comments, introduced special syntax

63. Documentation
Ongoing issue
Doxygen will no longer cut it (specific to C/C++)
Designed a custom format
Removed documentation comments, introduced special syntax
Converted all EFL/Elementary docs to the new format

64. Documentation
Ongoing issue
Doxygen will no longer cut it (specific to C/C++)
Designed a custom format
Removed documentation comments, introduced special syntax
Converted all EFL/Elementary docs to the new format
Still being extended and improved

65. Current situation

66. Current situation
We’re mostly done

67. Current situation
We’re mostly done
API is nice and clean

68. Current situation
We’re mostly done
API is nice and clean
All major issues are solved

69. Current situation
We’re mostly done
API is nice and clean
All major issues are solved
Documentation still ongoing

70. Current situation
We’re mostly done
API is nice and clean
All major issues are solved
Documentation still ongoing
Ownership handling still ongoing

71. The future
What are we going to do now?

72. Stabilize!

73. Stabilize!
Stabilization is the primary goal

74. Stabilize!
Stabilization is the primary goal
Not happening for a few more releases

75. Stabilize!
Stabilization is the primary goal
Not happening for a few more releases
We need to finalize documentation

76. Stabilize!
Stabilization is the primary goal
Not happening for a few more releases
We need to finalize documentation
We need to handle ownership

77. Stabilize!
Stabilization is the primary goal
Not happening for a few more releases
We need to finalize documentation
We need to handle ownership
Refactor the implementation and fix all quirks

78. More testing and changes

79. More testing and changes
We need more generators to help us test

80. More testing and changes
We need more generators to help us test
We also need to update all of EFL eo files

81. More testing and changes
We need more generators to help us test
We also need to update all of EFL eo files
This should help uncover any potential problems

82. Thank you.
Daniel Kolesa
Samsung Open Source Group
d.kolesa@osg.samsung.com
@octaforge
EFL Developer Day 2015