Video and slides synchronized, mp3 and slide download available at URL https://bit.ly/2TOCGtZ. Peter Alvaro talks about the reasons one should engage in language design and why many of us would (or should) do something so perverse as to design a language that no one will ever use. He shares some of the extreme and sometimes obnoxious opinions that guided his design process. Filmed at qconsf.com. Peter Alvaro is an Assistant Professor of Computer Science at the University of California Santa Cruz, where he leads the Disorderly Labs research group. His research focuses on using data-centric languages and analysis techniques to build and reason about data-intensive distributed systems, in order to make them scalable to the failures and nondeterminism endemic to large-scale distribution.

1. 3 things I wish I knew when I
started designing languages

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Watch the video with slide
synchronization on InfoQ.com!
https://www.infoq.com/presentations/
language-design-process

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Strategy
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Highlights
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Presented at QCon San Francisco
www.qconsf.com

4. About “poor me”
Systems
programming Me
Declarative
languages

5. About the real me
Flunked trig, flunked chem, never took calculus or physics.
Graduated HS with a 2.8 GPA
Bachelor of Arts in English Literature
3 years as an editor; 2 as a DBA; 5 as a software engineer before grad school
I am not nor was I ever a PL researcher

6. This talk is about me (designing a language)
1. Misgivings: how I almost never began
2. Lucky guesses: things I got right
3. Discoveries: stuff I learned along the way

7. Prelude: misapprehensions and misgivings
how we FUD ourselves out of language design

8. 1: The Look
An audacious new language
should look unique!

9. 1: The Need

10. 1: The Impact

11. Lucky guesses: things I got right

12. Lucky guess 1:
context context context context context context
context context context context context context
context context context context context context
context context context context context context
context context context context context context
context context context context context context
context context context context context context
context context context context context context

13. Every language is a DSL

14. Thy firmness makes my circle just
A domain

15. More lucky guesses: a damn problematic domain

16. Hiding and illuminating

17. What is damn hard about this domain?
Program correctness

18. What is damn hard about this domain?
Program correctness Debugging

19. What is damn hard about this domain?
Program correctness Debugging

20. What is damn hard about this domain?
Program correctness Debugging
Maintenance and extensibility

21. What is damn hard about this domain?
Program correctness Debugging
Maintenance and extensibility Heterogeneity and portability

22. Rearranging the deckchairs...
Program correctness Debugging
Maintenance and extensibility

23. Why so damn hard?

24. The right language would focus our attention on
How data flows through the system;
How it is allowed to change over time;
Where and when we can control how it changes and when we can’t.
Everything else, arguably, is a distraction

25. State representation
Control flow
Data
Time
context context context context context context context
context context context context context context context
context context context context context context context
context context context context context context context
context context context context context context context
context context context context context context context
context context context context context context context
context context context context context context context
context context context context context context context

26. Thy firmness makes my circle just
A domain
An opinion

27. Many moons passed

28. Inspiration

29. Descriptive complexity (Immerman’99)

30. Descriptive complexity (Immerman’99)

31. Descriptive complexity (Immerman’99)

32. Descriptive complexity (Immerman’99)

33. Queries made a neat lens...
create view response as
select client, server, code, document
from request r, page p
where r.server = p.server
and r.URI = p.URI;

34. Maybe languages are really lenses
Erlang
SQL

35. fragments
¬ σ π ⋈ LFP
Conjunctive queries

36. fragments
¬ σ π ⋈ LFP
SQL

37. fragments
¬ σ π ⋈ LFP
Datalog

38. Or maybe they are lassos
¬ σ π ⋈ LFP
Conjunctive queries
SQL
Datalog

39. context context context context context context
context context context context context context
context context context context context context
context context context context context context
context context context context context context
context context context context context context
context context context context context context
context context context context context context

40. Datacentrism
knowledge(“details”)

41. Datacentrism
knowledge(host1, “details”)
Contexualized by location (space)

42. Datalog cannot express
Mutable state
Uncertainty

43. Datacentrism
knowledge(host1, “details”, 27)
Contexualized by relative order (time)

44. Datacentrism
register(host1, “current value”, 27)

45. Datacentrism
kvs(host1, key, “current value”, 27)

46. Or maybe they are lassos
¬ σ π ⋈ LFP
Datalog

47. Or maybe they are lassos
¬ σ π ⋈ LFP
+1
“Statelog”

48. Dedalus can express it all. but...
¬ σ π ⋈ LFP
+1 ND choice
Dedalus

49. Dedalus allows us to say things we don’t want to
say; requires us to use stuff we’d rather not use
2PC 3PC
Paxos

50. Waiting requires counting
Counting requires waiting
(Joe Hellerstein)

51. ¬
Waiting requires counting
Nonmontonicity required to express coordination
Counting requires waiting
Coordination required to tolerate nonmonotonicity

52. Or maybe they are lassos
¬ σ π ⋈ LFP
+1 ND choice
CALM Dedalus

53. Pop descriptive complexity
Coordination-free programs
“Embarrassingly
parallel”
Dedalus
“Truly monotone”
dedalus
Semipositive
Dedalus
Dedalus0
Datalog
Halt
[....]
NP
P
[...]

54. Discoveries: stuff I learned along the way

55. Languages and the design process
context context context context context context context context context context
context context context context context context context context context context
context context context context context context context context context context
context context context context context context context context context context
context context context context context context context context context context
context context context context context context context context context context
context context context

56. Languages and the design process
Subject Object

57. Languages and the design process
Subject Object

58. Discoveries: stuff I learned along the way
The look

59. Discoveries: stuff I learned along the way
The look it’s about the fit

60. Discoveries: stuff I learned along the way
The look it’s about the fit
The need

61. Discoveries: stuff I learned along the way
The look it’s about the fit
The need it’s about our need

62. Discoveries: stuff I learned along the way
The look it’s about the fit
The need it’s about our need
The impact well….

64. Poor lucky me

65. BTW: Where’s the lie?

66. Watch the video with slide
synchronization on InfoQ.com!
https://www.infoq.com/presentations/
language-design-process