In this project my team and I tried our hands-on Functional Programming. Our aim was to compare challenges, efforts, and ease in developing a same application "MarkParser" (a Markdown parser) using both the paradigms.

1. O B J E C T O R I E N T E D V S F U N C T I O N A L
MARKPARSER

2. Utsav @kumar-utsav
Bhashwanth @bhashwanth
Our Team
Rohit @rarora4
Yatish @yatish27

3. Background...

4. What is OO Programming?
“Object-oriented programming (OOP) is a programming paradigm
based on the concept of objects which are data structures that
contain data, in the form of fields, often known as attributes; and
code, in the form of procedures, often known as methods.”
-Wikipedia

5. What is Functional Programming?
“In computer science, functional programming is a programming
paradigm, a style of building the structure and elements of computer
programs, that treats computation as the evaluation of mathematical
functions and avoids changing-state and mutable data.”
-Wikipedia

6. MarkParser
A package which converts markdown(.md) to HTML

7. Two Tracks

8. Design & Implementation...

9. Design:Object Oriented using Ruby
Class Document
Main class which encapsulates markdown string. It carries out the
parsing

10. Design:Object Oriented using Ruby
Class Element
- Base class for other element classes.
- Every Html element is an instance of this class.
- BlockElement: li, ol
- InlineElement: strong, em

11. Design:Object Oriented using Ruby

12. Utilizes...Higher Order Functions
Design:Functional Javascript

13. JSON Key-Value pair as dictionary
Design: Functional Javascript

14. Map & Reduce algorithms
STEP 1
Map
STEP 2
Reduce
STEP 3
Finalize
Design: Functional Javascript

15. Demo...

16. Demo...

17. Testing...

18. Supported Tags
Testing: Specification
Sample Markdown containing all tags
and equivalent HTML.

19. Rspec: Ruby testing framework
Testing: Tools
Jasmine: Javascript testing framework

20. Testing individual methods/functions in isolation
Testing: Unit Tests
Testing individual tags. eg h1, h2, ol

21. Assert equal entire markdown to HTML
Testing: Integration Tests
Test binary for file input, output files
Added ‘Live’ editor for Javascript track

22. Rubocop
Testing: Style Check
JSLint

23. Travis CI - Github Hook on master commit.
Testing: Automated Testing

24. Process & Tools...

25. Github issues based on Getting started,
Research, Requirement Analysis, MVP, Tests,
OO vs Functional Study
Process: Github Issue

26. Bug, Code, Ruby, Javascript, Process,
Prototype, Research, Redo, Results, Question,
Help wanted, Group work
Process: Github Issue
Needs Review, Awaiting Developer’s
Feedback, Ready to Merge, Merged

27. Process: Github Pull Requests & Labels

28. Methods: Github Pull Requests & Labels

29. Methods: Slack

30. Methods: Google Hangouts

31. Results & Discussion...

32. When we were new to
Object Oriented Programming
Results & Discussion

33. when…
we gained some expertise in OOPS
Results & Discussion

34. and when…
we started functional programming
Results & Discussion

35. What can be the reason???
Results & Discussion

36. Can be the way we
have been trained
Results & Discussion

37. Or may be….
Results & Discussion

38. by default we think and talk
in imperative terms
Results & Discussion

39. but we soon realized...
functional
Results & Discussion

40. as we described our team knew only OOPS
Results & Discussion

41. Results & Discussion
we would like to share our experience

42. so initially
functional == alien terms
Results & Discussion

43. Our Solution...
LEARN
Results & Discussion

44. and the results of our learnings...
MarkParser
Results & Discussion

45. and some points for discussion...
Results & Discussion

46. we think functional programming has higher
expressibility
Results & Discussion

47. Results & Discussion
we also think higher order functions make a lot
of sense in programming

48. Results & Discussion
we also think higher order functions make a lot
of sense in programming
also gives you a chance to put high school
mathematics into use

49. Part 1: Results & Discussion
a lot less time is spent in building and operating
on data structures
Results & Discussion

50. code for functional is very concise
in comparison to OOPS
Results & Discussion

51. however, we feel data encapsulation and abstraction
are easier to achieve in OOPS
Results & Discussion

52. refactoring code is easier, without telling the other
modules that don’t need to know
Results & Discussion

53. and at many instances, it was easier for us to think
in Object Oriented terms
OBJECT
Results & Discussion

54. rather than functional terms
Results & Discussion

55. some also claims that making GUI is easier in
OOPS but we have mixed opinion on that
Results & Discussion

56. So the question is which paradigm
is better?
Results & Discussion

57. So the question is which paradigm
is better?
FUNCTIONAL??
Results & Discussion

58. So the question is which paradigm
is better?
FUNCTIONAL??
(NO)
Results & Discussion

59. So the question is which paradigm
is better?
OOPS??
Results & Discussion

60. So the question is which paradigm
is better?
OOPS??
(NO)
Results & Discussion

61. Its like a fight between a bear and an alligator, the terrain
determines the outcome.
Results & Discussion

62. OOPS is generally better when there are fixed set of
OPERATIONS on things, and as code evolves new things are
added (e.g. new class)
Results & Discussion

63. Functional is generally good when there are fixed set of
THINGS, and as code evolves new operations are added to
existing things (e.g. avg func).
DATA
sum()
avg()
Results & Discussion

64. Conclusions...

65. Every programming paradigm consists of certain principal
features that makes solving particular set of problems much
easier/optimal
Universal Programming paradigm is a myth
Hybrid approach may involve some trade off, and chances of
messing up may increase
Conclusions

66. - https://github.com/jjyr/minidown
- https://github.com/gettalong/kramdown
- http://codepen.io/branneman/details/nbyrK/
- http://shamansir.github.io/blog/articles/generating-functional-
parsers/
- http://code.google.com/p/pagedown/
Other work in this area

67. - Add CSS for HTML
- Custom Markdown Tags
- Support for All Markdown tags
- Improve Testing
Future Work

68. - http://c2.com/cgi/wiki?OoVsFunctional
- http://www.srirangan.net/2011-12-functional-programming-in-
javascript
- http://functionaljavascript.blogspot.com/2013/07/monads.html
- https://developer.mozilla.org/en-
US/docs/Web/JavaScript/Guide/Regular_Expressions#special-
word-boundary
- http://stackoverflow.com/questions/2373524/how-do-i-display-
values-of-an-json-object
- http://www.ctrlshift.net/project/markdowneditor/
References