2. Agenda
●
Perspective
●
Preliminaries
●
On complecting
●
Overview of Zeder
●
Out of the Tar Pit
●
A Little Further out of the tar pit
●
Demo
●
Future

3. Preliminaries

12. Lens

19. st
Fogus' 1 Law
In the same way that an apple tree
“apples” – so too should your
systems “tuple”

22. [Entity Attribute Value]

23. Decomplecting

24. Take transients...
...please

25. Transients
●
Limited mutability
●
Thread isolated change
●
Not persistent
●
Not references
●
Speed boosts

26. Transients
●
Limited mutability
●
Thread isolated change
●
Not persistent
●
Not references
●
Speed boosts
Change policy

27. Transients
●
Limited mutability
●
Thread isolated change
●
Not persistent
●
Not references
●
Speed boosts
Change policy
Sharing policy

28. Transients
●
Limited mutability
●
Thread isolated change
●
Not persistent
●
Not references
●
Speed boosts
Change policy
Sharing policy

29. Transients
●
Limited mutability
●
Thread isolated change
●
Not persistent
●
Not references
●
Speed boosts
Change policy
Sharing policy
Reference policy

30. Transients
●
Limited mutability
●
Thread isolated change
●
Not persistent
●
Not references
●
Speed boosts
Change policy
Sharing policy
Reference policy
This is what you
wanted.

31. RAWG!?

32. Pods decomplect
●
Reference policy
●
Change policy

33. Zeder pods decomplect
●
Reference policy
●
Change policy
●
Sharing policy (Zeder version anyway)

34. Zeder pods decomplect
●
Reference policy
–
●
There are themselves references
Change policy
–
–
●
Transients internally
Mutable objects
Sharing policy (Zeder version anyway)
–
–
Single-thread
Multiple threads

35. A pod++
transient-of
value
value-of
writer
shareable?
reader

37. th
Fogus' 10 Rule
Any sufficiently complicated Clojure
program contains an ad hoc,
informally-specified, bug-ridden,
slow implementation of half of
OPS5.

38. OPS5
●
Invented in the late 1970s
●
Charles Forgy
●
Rete algorithm
●
Incredibly efficient
●
Used to develop expert systems (XCON)

39. OPS5

40. OPS5
{:db/ident :user/username … }
{:db/ident :user/salt … }
(defn store-user-info [uname]
@(transact connection
[{:user/username uname
:user/salt (gen-salt)}]))
;; something triggers a call
;; to store-user-info

41. OPS5
(literalize user
username
salt
)
{:db/ident :user/username … }
{:db/ident :user/salt … }
(p new-user
(user ^username <name>
^salt nil))
-->
(modify 1 ^salt “Bad salt”)
)
(defn store-user-info [uname]
@(transact connection
[{:user/username uname
:user/salt (gen-salt)}]))
(make user ^username fogus
;; something triggers a call

42. OPS5
(literalize user
username
salt
)
{:db/ident :user/username … }
{:db/ident :user/salt … }
(p new-user
(user ^username <name>
^salt nil))
-->
(modify 1 ^salt “Bad salt”)
)
(defn store-user-info [uname]
@(transact connection
[{:user/username uname
:user/salt (gen-salt)}]))
(make user ^username fogus
;; something triggers a call

43. OPS5
(literalize user
username
salt
)
{:db/ident :user/username … }
{:db/ident :user/salt … }
(p new-user
(user ^username <name>
^salt nil))
-->
(modify 1 ^salt “Bad salt”)
)
(defn store-user-info [uname]
@(transact connection
[{:user/username uname
:user/salt (gen-salt)}]))
(make user ^username fogus
;; something triggers a call

44. OPS5
(literalize user
username
salt
)
{:db/ident :user/username … }
{:db/ident :user/salt … }
(p new-user
(user ^username <name>
^salt nil))
-->
(modify 1 ^salt “Bad salt”)
)
(defn store-user-info [uname]
@(transact connection
[{:user/username uname
:user/salt (gen-salt)}]))
(make user ^username fogus
??
;; something triggers a call

45. Out of the
Tarpit
2006 by Ben Moseley and Peter
Marks

46. Decomplecting

47. Re
Decomplecting

52. Data
Behavior
Function

53. Data
Behavior
tactical
strategic
Function
tactical

56. Driving principles
●
Get stuff done
●
Data rocks
●
Don't invent anything
●
Protocols (swappable engines)
●
Pattern matching
●
Immutability (or the appearance thereof)
●
Fast would be nice

57. Things not shown
●
Snapshots
●
Rete implementation details
●
Pod details
●
Engine swaps
●
RHS Actions
●
LHS (match) predicates