What Is Pony?“Pony is an open-source, object-oriented, actor-model, capabilities-secure, high performance programming language.” -- ponylang.org
What Is Pony?“Pony is an open-source, object-oriented, actor-model, capabilities-secure, high performance programming language.” -- ponylang.org
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What Is Pony?“Pony is an open-source, object-oriented, actor-model, capabilities-secure, high performance programming language.” -- ponylang.org
Classes, Interfaces, Traits(but they may work a little differently than you expect)
What Is Pony?“Pony is an open-source, object-oriented, actor-model, capabilities-secure, high performance programming language.” -- ponylang.org
Actors communicate by passing messages to other
actors
What Is Pony?“Pony is an open-source, object-oriented, actor-model, capabilities-secure, high performance programming language.” -- ponylang.org
The compiler enforces what you can and cannot do with
an object
What Is Pony?“Pony is an open-source, object-oriented, actor-model, capabilities-secure, high performance programming language.” -- ponylang.org
Uses LLVM to compile to native code
What Is Pony?“Pony is an open-source, object-oriented, actor-model, capabilities-secure, high performance programming language.” -- ponylang.org
Also:
● powerful type system (unions, intersections, parameterized types and functions)
● fast actor-based garbage collection system
more-interesting.ponytrait Shape fun area(): F64
interface Named fun name(): String
class Circle is Shape let _radius: F64 new create(radius: F64) => _radius = radius fun name(): String => "circle" fun area(): F64 => 3.14159 * _radius * _radius
class Square is Shape let _side: F64 new create(side: F64) => _side = side fun name(): String => "square" fun area(): F64 => _side * _side
primitive AreaReporter fun report(shape: (Shape & Named)): String => "The area of this " + shape.name() + " is " + shape.area().string()
actor Main new create(env: Env) => let s: F64 = 15.3 var area = AreaReporter.report(Circle(s)) env.out.print(area) area = AreaReporter.report(Square(s)) env.out.print(area)
more-interesting.ponytrait Shape fun area(): F64
interface Named fun name(): String
class Circle is Shape let _radius: F64 new create(radius: F64) => _radius = radius fun name(): String => "circle" fun area(): F64 => 3.14159 * _radius * _radius
class Square is Shape let _side: F64 new create(side: F64) => _side = side fun name(): String => "square" fun area(): F64 => _side * _side
primitive AreaReporter fun report(shape: (Shape & Named)): String => "The area of this " + shape.name() + " is " + shape.area().string()
actor Main new create(env: Env) => let s: F64 = 15.3 var area = AreaReporter.report(Circle(s)) env.out.print(area) area = AreaReporter.report(Square(s)) env.out.print(area)
more-interesting.ponytrait Shape fun area(): F64
interface Named fun name(): String
class Circle is Shape let _radius: F64 new create(radius: F64) => _radius = radius fun name(): String => "circle" fun area(): F64 => 3.14159 * _radius * _radius
class Square is Shape let _side: F64 new create(side: F64) => _side = side fun name(): String => "square" fun area(): F64 => _side * _side
primitive AreaReporter fun report(shape: (Shape & Named)): String => "The area of this " + shape.name() + " is " + shape.area().string()
actor Main new create(env: Env) => let s: F64 = 15.3 var area = AreaReporter.report(Circle(s)) env.out.print(area) area = AreaReporter.report(Square(s)) env.out.print(area)
traits: nominal subtyping
more-interesting.ponytrait Shape fun area(): F64
interface Named fun name(): String
class Circle is Shape let _radius: F64 new create(radius: F64) => _radius = radius fun name(): String => "circle" fun area(): F64 => 3.14159 * _radius * _radius
class Square is Shape let _side: F64 new create(side: F64) => _side = side fun name(): String => "square" fun area(): F64 => _side * _side
primitive AreaReporter fun report(shape: (Shape & Named)): String => "The area of this " + shape.name() + " is " + shape.area().string()
actor Main new create(env: Env) => let s: F64 = 15.3 var area = AreaReporter.report(Circle(s)) env.out.print(area) area = AreaReporter.report(Square(s)) env.out.print(area)
more-interesting.ponytrait Shape fun area(): F64
interface Named fun name(): String
class Circle is Shape let _radius: F64 new create(radius: F64) => _radius = radius fun name(): String => "circle" fun area(): F64 => 3.14159 * _radius * _radius
class Square is Shape let _side: F64 new create(side: F64) => _side = side fun name(): String => "square" fun area(): F64 => _side * _side
primitive AreaReporter fun report(shape: (Shape & Named)): String => "The area of this " + shape.name() + " is " + shape.area().string()
actor Main new create(env: Env) => let s: F64 = 15.3 var area = AreaReporter.report(Circle(s)) env.out.print(area) area = AreaReporter.report(Square(s)) env.out.print(area)
interfaces: structural subtyping
more-interesting.ponytrait Shape fun area(): F64
interface Named fun name(): String
class Circle is Shape let _radius: F64 new create(radius: F64) => _radius = radius fun name(): String => "circle" fun area(): F64 => 3.14159 * _radius * _radius
class Square is Shape let _side: F64 new create(side: F64) => _side = side fun name(): String => "square" fun area(): F64 => _side * _side
primitive AreaReporter fun report(shape: (Shape & Named)): String => "The area of this " + shape.name() + " is " + shape.area().string()
actor Main new create(env: Env) => let s: F64 = 15.3 var area = AreaReporter.report(Circle(s)) env.out.print(area) area = AreaReporter.report(Square(s)) env.out.print(area)
more-interesting.ponytrait Shape fun area(): F64
interface Named fun name(): String
class Circle is Shape let _radius: F64 new create(radius: F64) => _radius = radius fun name(): String => "circle" fun area(): F64 => 3.14159 * _radius * _radius
class Square is Shape let _side: F64 new create(side: F64) => _side = side fun name(): String => "square" fun area(): F64 => _side * _side
primitive AreaReporter fun report(shape: (Shape & Named)): String => "The area of this " + shape.name() + " is " + shape.area().string()
actor Main new create(env: Env) => let s: F64 = 15.3 var area = AreaReporter.report(Circle(s)) env.out.print(area) area = AreaReporter.report(Square(s)) env.out.print(area)
more-interesting.ponytrait Shape fun area(): F64
interface Named fun name(): String
class Circle is Shape let _radius: F64 new create(radius: F64) => _radius = radius fun name(): String => "circle" fun area(): F64 => 3.14159 * _radius * _radius
class Square is Shape let _side: F64 new create(side: F64) => _side = side fun name(): String => "square" fun area(): F64 => _side * _side
primitive AreaReporter fun report(shape: (Shape & Named)): String => "The area of this " + shape.name() + " is " + shape.area().string()
actor Main new create(env: Env) => let s: F64 = 15.3 var area = AreaReporter.report(Circle(s)) env.out.print(area) area = AreaReporter.report(Square(s)) env.out.print(area)
primitive: object with no data and only one instance
more-interesting.ponytrait Shape fun area(): F64
interface Named fun name(): String
class Circle is Shape let _radius: F64 new create(radius: F64) => _radius = radius fun name(): String => "circle" fun area(): F64 => 3.14159 * _radius * _radius
class Square is Shape let _side: F64 new create(side: F64) => _side = side fun name(): String => "square" fun area(): F64 => _side * _side
primitive AreaReporter fun report(shape: (Shape & Named)): String => "The area of this " + shape.name() + " is " + shape.area().string()
actor Main new create(env: Env) => let s: F64 = 15.3 var area = AreaReporter.report(Circle(s)) env.out.print(area) area = AreaReporter.report(Square(s)) env.out.print(area)
more-interesting.ponytrait Shape fun area(): F64
interface Named fun name(): String
class Circle is Shape let _radius: F64 new create(radius: F64) => _radius = radius fun name(): String => "circle" fun area(): F64 => 3.14159 * _radius * _radius
class Square is Shape let _side: F64 new create(side: F64) => _side = side fun name(): String => "square" fun area(): F64 => _side * _side
primitive AreaReporter fun report(shape: (Shape & Named)): String => "The area of this " + shape.name() + " is " + shape.area().string()
actor Main new create(env: Env) => let s: F64 = 15.3 var area = AreaReporter.report(Circle(s)) env.out.print(area) area = AreaReporter.report(Square(s)) env.out.print(area)
> ./ponyc src/more-interesting> ./more-interestingThe area of this circle is 735.415The area of this square is 234.09>
Pony: The Really Interesting PartsPony uses actors and reference capabilities to allow the compiler to guarantee that a program is data-race-free.
Pony: The Really Interesting PartsPony uses actors and reference capabilities to allow the compiler to guarantee that a program is data-race-free.
Pony: The Really Interesting PartsPony uses actors and reference capabilities to allow the compiler to guarantee
that a program is data-race-free.
Pony: The Really Interesting PartsPony uses actors and reference capabilities to allow the compiler to guarantee
that a program is data-race-free.
Pony: The Really Interesting PartsPony uses actors and reference capabilities to allow the compiler to guarantee
that a program is data-race-free.
Pony: The Really Interesting PartsPony uses actors and reference capabilities to allow the compiler to guarantee
that a program is data-race-free.
Pony: The Really Interesting PartsPony uses actors and reference capabilities to allow the compiler to guarantee that a program is
data-race-free.
Off To The Data Races!Some pseudo code (not Pony) …
global int a = 0
function inc() { for x in range(0, 1000001) { a = a + 1 }}
function main() { inc() print(“a = “ + a)}
1000000
Off To The Data Races!Some more pseudo code (not Pony) …
global int a = 0
function inc() { for x in range(0, 1000001) { a = a + 1 }}
function main() { thread thread1 = Thread(inc) thread thread2 = Thread(inc) thread1.run() thread2.run() thread1.join() thread2.join() print(“a = “ + a)}
● Run “inc()” simultaneously in two places
● wait for both runs to finish● print the value of “a”
Off To The Data Races!Some more pseudo code (not Pony) …
global int a = 0
function inc() { for x in range(0, 1000001) { a = a + 1 }}
function main() { thread thread1 = Thread(inc) thread thread2 = Thread(inc) thread1.run() thread2.run() thread1.join() thread2.join() print(“a = “ + a)}
Expected (two threads each
incrementing a variable
1000000 times):
2000000
Off To The Data Races!Some more pseudo code (not Pony) …
global int a = 0
function inc() { for x in range(0, 1000001) { a = a + 1 }}
function main() { thread thread1 = Thread(inc) thread thread2 = Thread(inc) thread1.run() thread2.run() thread1.join() thread2.join() print(“a = “ + a)}
Expected:
2000000
Actual Run 1:
1987735
Actual Run 2:
1935010
Actual Run 3:
1941217
Off To The Data Races!Some more pseudo code (not Pony) …
global int a = 0
function inc() { for x in range(0, 1000001) { a = a + 1 }}
function main() { thread thread1 = Thread(inc) thread thread2 = Thread(inc) thread1.run() thread2.run() thread1.join() thread2.join() print(“a = “ + a)}
Expected:
2000000
Actual Run 1:
1987735
Actual Run 2:
1935010
Actual Run 3:
1941217
WHY?
Off To The Data Races!In thread1 …
// get the value of “a”// add 1 to that value// write the new value back to “a”a = a + 1
Meanwhile, in thread2...
// get the value of “a”// add 1 to that value// write the new value back to “a”a = a + 1
a = 26
Off To The Data Races!In thread1 …
// get the value of “a” 26// add 1 to that value// write the new value back to “a”a = a + 1
Meanwhile, in thread2...
// get the value of “a” 26// add 1 to that value// write the new value back to “a”a = a + 1
a = 26
Off To The Data Races!In thread1 …
// get the value of “a” 26// add 1 to that value 26 + 1 = 27// write the new value back to “a”a = a + 1
Meanwhile, in thread2...
// get the value of “a” 26// add 1 to that value 26 + 1 = 27// write the new value back to “a”a = a + 1
a = 26
Off To The Data Races!In thread1 …
// get the value of “a” 26// add 1 to that value 26 + 1 = 27// write the new value back to “a” a = 27a = a + 1
Meanwhile, in thread2...
// get the value of “a” 26// add 1 to that value 26 + 1 = 27// write the new value back to “a” a = 27a = a + 1
a = 27
Off To The Data Races!In thread1 …
// get the value of “a” 26// add 1 to that value 26 + 1 = 27// write the new value back to “a” a = 27a = a + 1
Meanwhile, in thread2...
// get the value of “a” 26// add 1 to that value 26 + 1 = 27// write the new value back to “a” a = 27a = a + 1
a = 27
We wanted a = 28
Off To The Data Races!In thread1 …
// get the value of “a” 26// add 1 to that value 26 + 1 = 27// write the new value back to “a” a = 27a = a + 1
Meanwhile, in thread2...
// get the value of “a” 26// add 1 to that value 26 + 1 = 27// write the new value back to “a” a = 27a = a + 1
a = 27
This may not happen every time, but each time it happens it increases the error of the result.
We wanted a = 28
Off To The Data Races!In thread1 …
// get the value of “a” 26// add 1 to that value 26 + 1 = 27// write the new value back to “a” a = 27a = a + 1
Meanwhile, in thread2...
// get the value of “a” 26// add 1 to that value 26 + 1 = 27// write the new value back to “a” a = 27a = a + 1
a = 27
This may not happen every time, but each time it happens it increases the error of the result.
We wanted a = 28
“Shared mutable state is the root of all evil.” -- several different people, all at the same time
Off To The Data Races!Techniques various and sundry for avoiding data races ...
● Locks! → a unit of execution acquires a lock, no other unit of execution can acquire the lock until it is released
○ C and C++
● Synchronized blocks/functions/methods! → somebody writes the locks for you○ Java
● Everything is read-only! → don’t need to worry about writes anymore○ Erlang
● There’s only one binding to an object at any time! → move, borrow, copy○ Rust
Leaving The Data RacesPony uses two rules to avoid data races:
● The Read Rule: If an actor can read an object then no other actor can modify that object
● The Write Rule: If an actor can modify an object then no other actor can read or modify it
Actors
Get next message
Processmessage
Collect garbage
message3message4
message1message2 } Queue
In reality messages are processed in batches, GC is done between batches
Actors
a1.bar() a2.baz() a1.bar()
a3.dee() a4.doo() a3.doh()
a5.moo()
a8.fee() a7.foo()
a6.mee()
a7.fuz()
time
CPU1: thread1
CPU2: thread2
CPU3: thread3
CPU4: thread4
Actors run on threads (1 thread per CPU by default)
Actors
a1.bar() a2.baz() a1.bar()
a3.dee() a4.doo() a3.doh()
a5.moo()
a8.fee() a7.foo()
a6.mee()
a7.fuz()
time
CPU1: thread1
CPU2: thread2
CPU3: thread3
CPU4: thread4
Actors are assigned to a specific threada1, a2
a3, a4
a5, a6
a7, a8
Actors
a1.bar() a2.baz()1 a1.bar()
a3.dee() a4.doo() a3.doh()
a5.moo()
a8.fee() a7.foo()
a6.mee()
a7.fuz()
time
CPU1: thread1
CPU2: thread2
CPU3: thread3
CPU4: thread4
a2.baz()2
Behaviors cannot be preempted
Actors
a1.bar() a2.baz() a1.bar()
IDLE a1.baz() a3.doh()
a5.moo()
a8.fee() a7.foo()
a6.mee()
a7.fuz()
time
CPU1: thread1
CPU2: thread2
CPU3: thread3
CPU4: thread4
A idle thread “steal” work from another thread
Work for actor a1 “stolen” by thread2
Actors
a1.bar() a2.baz() a1.bar()
a1.buz() a4.doo() a3.doh()
a5.moo()
a8.fee() a7.foo()
a6.mee()
a7.fuz()
time
CPU1: thread1
CPU2: thread2
CPU3: thread3
CPU4: thread4
Actors process one message at a time (actors are effectively single-threaded)
Actors
a1 a3
a2
o1
Actors have references to objects and other actors
References can be used to:* read from an object* write to an object* send messages to another actor
Actors
a1 a3
a2
o1
Actors have references to objects and other actors
References can be used to:* read from an object* write to an object* send messages to another actor
Reference Capabilities control whether reads and writes are allowed via a given reference. Any reference can be used to send a message.
Actors
a1 a3
a2
o1
Actors have references to objects and other actors
References can be used to:* read from an object* write to an object* send messages to another actor
Reference Capabilities control whether reads and writes are allowed via a given reference. Any reference can be used to send a message.
Note: send message ≠ read/write
Actors: An Example
actor Example
var _text: String
new create(text: String) =>
_text = text
be foo(o: Other) =>
o.say(rev())
fun ref rev(): String val =>
_text = recover
_text.reverse()
end
_text
actor Other
let _env: Env
new create(env: Env) =>
_env = env
be say(s: String) =>
_env.out.print(s)
actor Main
new create(env: Env) =>
let e = Example("howdy")
let o = Other(env)
e.foo(o) // prints “ydwoh”
e.foo(o) // prints “howdy”
Actors: An Example
actor Example
var _text: String
new create(text: String) =>
_text = text
be foo(o: Other) =>
o.say(rev())
fun ref rev(): String val =>
_text = recover
_text.reverse()
end
_text
actor Other
let _env: Env
new create(env: Env) =>
_env = env
be say(s: String) =>
_env.out.print(s)
actor Main
new create(env: Env) =>
let e = Example("howdy")
let o = Other(env)
e.foo(o) // prints “ydwoh”
e.foo(o) // prints “howdy”
Main
create(env)
run!
When the program starts, the Main actor is instantiated and a create message is sent to it.
Actors: An Example
actor Example
var _text: String
new create(text: String) =>
_text = text
be foo(o: Other) =>
o.say(rev())
fun ref rev(): String val =>
_text = recover
_text.reverse()
end
_text
actor Other
let _env: Env
new create(env: Env) =>
_env = env
be say(s: String) =>
_env.out.print(s)
actor Main
new create(env: Env) =>
let e = Example("howdy")
let o = Other(env)
e.foo(o) // prints “ydwoh”
e.foo(o) // prints “howdy”
Maincreate(env)
The Main actor begins to process the create message.
Actors: An Example
actor Example
var _text: String
new create(text: String) =>
_text = text
be foo(o: Other) =>
o.say(rev())
fun ref rev(): String val =>
_text = recover
_text.reverse()
end
_text
actor Other
let _env: Env
new create(env: Env) =>
_env = env
be say(s: String) =>
_env.out.print(s)
actor Main
new create(env: Env) =>
let e = Example("howdy")
let o = Other(env)
e.foo(o) // prints “ydwoh”
e.foo(o) // prints “howdy”
Main e
create(“howdy”)
create(env)
An instance of the Example actor is instantiated and a create message is sent to it with “howdy” as the argument.
Actors: An Example
actor Example
var _text: String
new create(text: String) =>
_text = text
be foo(o: Other) =>
o.say(rev())
fun ref rev(): String val =>
_text = recover
_text.reverse()
end
_text
actor Other
let _env: Env
new create(env: Env) =>
_env = env
be say(s: String) =>
_env.out.print(s)
actor Main
new create(env: Env) =>
let e = Example("howdy")
let o = Other(env)
e.foo(o) // prints “ydwoh”
e.foo(o) // prints “howdy”
Main e
create(env)
o
create(“howdy)
create(env)
An instance of the the Other actor is instantiated and a create message is sent to it with env as the argument.
Actors: An Example
actor Example
var _text: String
new create(text: String) =>
_text = text
be foo(o: Other) =>
o.say(rev())
fun ref rev(): String val =>
_text = recover
_text.reverse()
end
_text
actor Other
let _env: Env
new create(env: Env) =>
_env = env
be say(s: String) =>
_env.out.print(s)
actor Main
new create(env: Env) =>
let e = Example("howdy")
let o = Other(env)
e.foo(o) // prints “ydwoh”
e.foo(o) // prints “howdy”
Maincreate(env)create(“howdy)
foo(o)
e_text=”howdy”
o_env=envcreate(env)
The Main actor sends a foo message to the Example actor.
The Example actor sets the value of its _text field.
The Other actor sets the value of its _env field
Actors: An Example
actor Example
var _text: String
new create(text: String) =>
_text = text
be foo(o: Other) =>
o.say(rev())
fun ref rev(): String val =>
_text = recover
_text.reverse()
end
_text
actor Other
let _env: Env
new create(env: Env) =>
_env = env
be say(s: String) =>
_env.out.print(s)
actor Main
new create(env: Env) =>
let e = Example("howdy")
let o = Other(env)
e.foo(o) // prints “ydwoh”
e.foo(o) // prints “howdy”
Main e_text=”howdy”
o_env=env
foo(o)1
foo(o)2
create(env)
The Main actor sends a foo message to the Example actor.
The Example actor sets the value of its _text field.
The Other actor sets the value of its _env field
foo(o)1
Actors: An Example
actor Example
var _text: String
new create(text: String) =>
_text = text
be foo(o: Other) =>
o.say(rev())
fun ref rev(): String val =>
_text = recover
_text.reverse()
end
_text
actor Other
let _env: Env
new create(env: Env) =>
_env = env
be say(s: String) =>
_env.out.print(s)
actor Main
new create(env: Env) =>
let e = Example("howdy")
let o = Other(env)
e.foo(o) // prints “ydwoh”
e.foo(o) // prints “howdy”
Main e_text=”ydwoh”
o_env=env
foo(o)2
The Example actor processes the first foo message by first calling its rev method, which reverses the _text string.
foo(o)1
Actors: An Example
actor Example
var _text: String
new create(text: String) =>
_text = text
be foo(o: Other) =>
o.say(rev())
fun ref rev(): String val =>
_text = recover
_text.reverse()
end
_text
actor Other
let _env: Env
new create(env: Env) =>
_env = env
be say(s: String) =>
_env.out.print(s)
actor Main
new create(env: Env) =>
let e = Example("howdy")
let o = Other(env)
e.foo(o) // prints “ydwoh”
e.foo(o) // prints “howdy”
Main e_text=”ydwoh”
o_env=env
foo(o)2 say(“ydwoh”)
The Example actor sends the string to the Other actor in a say message.
say(“ydwoh”)foo(o)2
Actors: An Example
actor Example
var _text: String
new create(text: String) =>
_text = text
be foo(o: Other) =>
o.say(rev())
fun ref rev(): String val =>
_text = recover
_text.reverse()
end
_text
actor Other
let _env: Env
new create(env: Env) =>
_env = env
be say(s: String) =>
_env.out.print(s)
actor Main
new create(env: Env) =>
let e = Example("howdy")
let o = Other(env)
e.foo(o) // prints “ydwoh”
e.foo(o) // prints “howdy”
Main e_text=”howdy”
o_env=env
YDWOH
The Example actor processes the second foo message, which again reverses the _text string.
The Other actor processes the say message by printing the string that it received.
foo(o)2
Actors: An Example
actor Example
var _text: String
new create(text: String) =>
_text = text
be foo(o: Other) =>
o.say(rev())
fun ref rev(): String val =>
_text = recover
_text.reverse()
end
_text
actor Other
let _env: Env
new create(env: Env) =>
_env = env
be say(s: String) =>
_env.out.print(s)
actor Main
new create(env: Env) =>
let e = Example("howdy")
let o = Other(env)
e.foo(o) // prints “ydwoh”
e.foo(o) // prints “howdy”
Main e_text=”howdy”
o_env=env
say(“howdy”)
YDWOH
The Example actor sends another say message to the Other actor.
say(“howdy”)
Actors: An Example
actor Example
var _text: String
new create(text: String) =>
_text = text
be foo(o: Other) =>
o.say(rev())
fun ref rev(): String val =>
_text = recover
_text.reverse()
end
_text
actor Other
let _env: Env
new create(env: Env) =>
_env = env
be say(s: String) =>
_env.out.print(s)
actor Main
new create(env: Env) =>
let e = Example("howdy")
let o = Other(env)
e.foo(o) // prints “ydwoh”
e.foo(o) // prints “howdy”
Main e_text=”howdy”
o_env=env
YDWOHHOWDY
The Other actor processes the say message by printing the string that it received.
Actors: An Example
actor Example
var _text: String
new create(text: String) =>
_text = text
be foo(o: Other) =>
o.say(rev())
fun ref rev(): String val =>
_text = recover
_text.reverse()
end
_text
actor Other
let _env: Env
new create(env: Env) =>
_env = env
be say(s: String) =>
_env.out.print(s)
actor Main
new create(env: Env) =>
let e = Example("howdy")
let o = Other(env)
e.foo(o) // prints “ydwoh”
e.foo(o) // prints “howdy”
Main e_text=”howdy”
o_env=env
YDWOHHOWDY
All messages have been handled so the program can exit.
Reference CapabilitiesRemember the Read Rule and the Write Rule:
● The Read Rule: If an actor can read an object then no other actor can modify that object
● The Write Rule: If an actor can modify an object then no other actor can read or modify it
Reference CapabilitiesReference capabilities control whether a given alias can be used to read or modify an object.
The collection of reference capabilities for aliases that refer to an object must be consistent with the Read Rule and the Write Rule.
Any alias to an actor, regardless of reference capability, can be used to send messages to that actor.
Reference CapabilitiesThere are six reference capabilities:
● iso - only one alias can be used to read or modify this object● trn - only one alias can modify this object, but more than one alias can be
used to read it● val - no alias can modify this object, but more than one alias can read from it● ref - more than one alias can read from this object, and more than alias can
modify this object● box - this alias can be used to read an object, there may more may not be
more than one other alias that can modify it● tag - this alias cannot be used to read or modify this object (but it can be
used to send a message or do an identity comparison)
Reference CapabilitiesReference capabilities can appear in
● variable, parameter, and field declarations○ let foo: Foo ref = Foo // foo’s reference capability is ref
Reference CapabilitiesReference capabilities can appear in
● variable, parameter, and field declarations○ let foo: Foo ref = Foo // foo’s reference capability is ref
● actor and class declarations○ class val Foo // a “Foo” type means “Foo val” unless otherwise specified
Reference CapabilitiesReference capabilities can appear in
● variable, parameter, and field declarations○ let foo: Foo ref = Foo // foo’s reference capability is ref
● actor and class declarations○ class val Foo // a “Foo” type means “Foo val” unless otherwise specified
● constructor declarations○ new val create() => // objects of this class will have a reference capability of val
Reference CapabilitiesReference capabilities can appear in
● variable, parameter, and field declarations○ let foo: Foo ref = Foo // foo’s reference capability is ref
● actor and class declarations○ class val Foo // a “Foo” type means “Foo val” unless otherwise specified
● constructor declarations○ new val create() => // objects of this class will have a reference capability of val
● function declarations○ fun ref bar() // bar()’s receiver must have a reference capability of ref
Reference CapabilitiesReference capabilities can appear in
● variable, parameter, and field declarations○ let foo: Foo ref = Foo // foo’s reference capability is ref
● actor and class declarations○ class val Foo // a “Foo” type means “Foo val” unless otherwise specified
● constructor declarations○ new val create() => // objects of this class will have a reference capability of val
● function declarations○ fun ref bar() // bar()’s receiver must have a reference capability of ref
● function return values○ fun f(): String ref // the String will have a reference capability of ref
Reference CapabilitiesReference capabilities can appear in
● variable, parameter, and field declarations○ let foo: Foo ref = Foo // foo’s reference capability is ref
● actor and class declarations○ class val Foo // a “Foo” type means “Foo val” unless otherwise specified
● constructor declarations○ new val create() => // objects of this class will have a reference capability of val
● function declarations○ fun ref bar() // bar()’s receiver must have a reference capability of ref
● function return values○ fun f(): String ref // the String will have a reference capability of ref
● recover blocks○ recover iso … end // the reference capability of the returned object will be iso
Reference CapabilitiesIf no reference capability is specified, the default reference capability for the given thing is used.
Reference Capabilitiesclass Foo
class val Bar let v: U32 new val create(vv: U32) => v = vv
actor Main new create(env: Env) => let a: Foo iso = recover Foo end var b = Bar(1) b = Bar(2) baz(b) fun baz(c: Bar): U32 => c.v + 16
Reference CapabilitiesSPOT THE REFERENCE CAPABILITIES!
class Foo
class val Bar let v: U32 new val create(vv: U32) => v = vv
actor Main new create(env: Env) => let a: Foo iso = recover Foo end var b = Bar(1) b = Bar(2) baz(b) fun baz(c: Bar): U32 => c.v + 16
Reference CapabilitiesSPOT THE EXPLICIT REFERENCE CAPABILITIES!
SPOT THE IMPLIED REFERENCE CAPABILITIES!
class ref Foo
class val Bar let v: U32 val new val create(vv: U32 val) => v = vv
actor tag Main new create(env: Env val) => let a: Foo iso = recover iso Foo end var b: Bar val = Bar(1) b = Bar(2) baz(b) fun box baz(c: Bar val): U32 val => c.v + 16
Reference CapabilitiesActors have a default reference capability of tag, objects created from classes have a default reference capability of ref
class ref Foo
class val Bar let v: U32 val new val create(vv: U32 val) => v = vv
actor tag Main new create(env: Env val) => let a: Foo iso = recover iso Foo end var b: Bar val = Bar(1) b = Bar(2) baz(b) fun box baz(c: Bar val): U32 val => c.v + 16
Reference CapabilitiesYou can change the implicit reference capability of a class (normally it is ref)
You can change the reference capability of the object generated by the constructor (normally it is ref)
class ref Foo
class val Bar let v: U32 val new val create(vv: U32 val) => v = vv
actor tag Main new create(env: Env val) => let a: Foo iso = recover iso Foo end var b: Bar val = Bar(1) b = Bar(2) baz(b) fun box baz(c: Bar val): U32 val => c.v + 16
Reference CapabilitiesYou can specify the type of reference capability that the receiver must have to call a function
class ref Foo
class val Bar let v: U32 val new val create(vv: U32 val) => v = vv
actor tag Main new create(env: Env val) => let a: Foo iso = recover iso Foo end var b: Bar val = Bar(1) b = Bar(2) baz(b) fun box baz(c: Bar val): U32 val => c.v + 16
Reference CapabilitiesYou can specify the type of reference capability that the receiver must have to call a function
This can get really tricky!
class ref Foo
class val Bar let v: U32 val new val create(vv: U32 val) => v = vv
actor tag Main new create(env: Env val) => let a: Foo iso = recover iso Foo end var b: Bar val = Bar(1) b = Bar(2) baz(b) fun box baz(c: Bar val): U32 val => c.v + 16
Reference CapabilitiesAn alias is a name given to a particular object in memory
Aliases are created when
● an object is assigned to a variable● an object is passed as an argument to a
method
class Foo
class val Bar let v: U32 new val create(vv: U32) => v = vv
actor Main new create(env: Env) => let a: Foo iso = recover Foo end var b = Bar(1) b = Bar(2) baz(b) fun baz(c: Bar): U32 => c.v + 16
Reference CapabilitiesAn alias is a name given to a particular object in memory
Aliases are created when
● an object is assigned to a variable● an object is passed as an argument to a
method
class Foo
class val Bar let v: U32 new val create(vv: U32) => v = vv
actor Main new create(env: Env) => let a: Foo iso = recover Foo end var b = Bar(1) b = Bar(2) baz(b) fun baz(c: Bar): U32 => c.v + 16
Reference CapabilitiesAn alias is a name given to a particular object in memory
Aliases are created when
● an object is assigned to a variable● an object is passed as an argument to a
method
class Foo
class val Bar let v: U32 new val create(vv: U32) => v = vv
actor Main new create(env: Env) => let a: Foo iso = recover Foo end var b = Bar(1) b = Bar(2) baz(b) fun baz(c: Bar): U32 => c.v + 16
Reference CapabilitiesAn alias is a name given to a particular object in memory
Aliases are created when
● an object is assigned to a variable● an object is passed as an argument to a
method
class Foo
class val Bar let v: U32 new val create(vv: U32) => v = vv
actor Main new create(env: Env) => let a: Foo iso = recover Foo end var b = Bar(1) b = Bar(2) baz(b) fun baz(c: Bar): U32 => c.v + 16
Reference CapabilitiesAn alias is a name given to a particular object in memory
Aliases are created when
● an object is assigned to a variable● an object is passed as an argument to a
method
class Foo
class val Bar let v: U32 new val create(vv: U32) => v = vv
actor Main new create(env: Env) => let a: Foo iso = recover Foo end var b = Bar(1) b = Bar(2) baz(b) fun baz(c: Bar): U32 => c.v + 16
Reference CapabilitiesAn object may have more than one alias, possibly in more than one actor, but the combination of aliases must not violate the read rule and write rule.
● The Read Rule: If an actor can read an object then no other actor can modify that object
● The Write Rule: If an actor can modify an object then no other actor can read or modify it
class Foo
class val Bar let v: U32 new val create(vv: U32) => v = vv
actor Main new create(env: Env) => let a: Foo iso = recover Foo end var b = Bar(1) b = Bar(2) baz(b) fun baz(c: Bar): U32 => c.v + 16
Reference Capabilities: iso (isolated)● The Read Rule: If an
actor can read an object then no other actor can modify that object
● The Write Rule: If an actor can modify an object then no other actor can read or modify it
iso reference can read and modify an object. No other reference can read or modify the object.
object
alias1
alias2
alias3
Actor A Actor B
iso
Reference Capabilities: trn (transitional)● The Read Rule: If an
actor can read an object then no other actor can modify that object
● The Write Rule: If an actor can modify an object then no other actor can read or modify it
trn reference can read and modify an object. No other reference can modify the object, but the actor may have other references that can read the object.
object
alias1
alias2
alias3
Actor A Actor B
trn
Reference Capabilities: ref (reference)● The Read Rule: If an
actor can read an object then no other actor can modify that object
● The Write Rule: If an actor can modify an object then no other actor can read or modify it
ref reference can read and modify an object. Other references in the actor may be able to read or modify the object, but no other actor may have a reference that can read or modify it.
object
alias1
alias2
alias3
Actor A Actor B
ref
Reference Capabilities: val (value)● The Read Rule: If an
actor can read an object then no other actor can modify that object
● The Write Rule: If an actor can modify an object then no other actor can read or modify it
val reference can read an object. The actor may have other references that can read the object, and other actors may have references that can read the object, but no actor may have a reference that can modify it.
object
alias1
alias2
alias3
Actor A Actor B
val
Reference Capabilities: box (box)● The Read Rule: If an
actor can read an object then no other actor can modify that object
● The Write Rule: If an actor can modify an object then no other actor can read or modify it
object
alias1
alias2
alias3
Actor A Actor B
box
OR
object
alias1
alias2
alias3
Actor A Actor B
box
Reference Capabilities: box (box)● The Read Rule: If an
actor can read an object then no other actor can modify that object
● The Write Rule: If an actor can modify an object then no other actor can read or modify it
object
alias1
alias2
alias3
Actor A Actor B
box
OR
object
alias1
alias2
alias3
Actor A Actor B
box
This looks like a val
This looks like a ref
A box capability is used when you want to create a new read-only reference to an object that is either val or ref.
Reference Capabilities: box (box)class X let v: I32 new create(v': I32) => v = v'
actor Main new create(env: Env) => let a: X ref = X(7) let b: X val = recover X(8) end bar(a) bar(b) fun bar(x: X ???): I32 => x.v() + 1
What should the reference capability be?
Reference Capabilities: box (box)class X let v: I32 new create(v': I32) => v = v'
actor Main new create(env: Env) => let a: X ref = X(7) let b: X val = recover X(8) end bar(a) bar(b) fun bar(x: X ref): I32 => x.v() + 1
Reference Capabilities: box (box)class X let v: I32 new create(v': I32) => v = v'
actor Main new create(env: Env) => let a: X ref = X(7) let b: X val = recover X(8) end bar(a) bar(b) fun bar(x: X ref): I32 => x.v() + 1
ref doesn’t work because a ref (x) can’t alias a val (b)
Reference Capabilities: box (box)class X let v: I32 new create(v': I32) => v = v'
actor Main new create(env: Env) => let a: X ref = X(7) let b: X val = recover X(8) end bar(a) bar(b) fun bar(x: X ref): I32 => x.v() + 1
class X let v: I32 new create(v': I32) => v = v'
actor Main new create(env: Env) => let a: X ref = X(7) let b: X val = recover X(8) end bar(a) bar(b) fun bar(x: X val): I32 => x.v() + 1
ref doesn’t work because a ref (x) can’t alias a val (b)
Reference Capabilities: box (box)class X let v: I32 new create(v': I32) => v = v'
actor Main new create(env: Env) => let a: X ref = X(7) let b: X val = recover X(8) end bar(a) bar(b) fun bar(x: X ref): I32 => x.v() + 1
class X let v: I32 new create(v': I32) => v = v'
actor Main new create(env: Env) => let a: X ref = X(7) let b: X val = recover X(8) end bar(a) bar(b) fun bar(x: X val): I32 => x.v() + 1
ref doesn’t work because a ref (x) can’t alias a val (b)
val Doesn’t work because a val (x) can’t alias a ref (a)
Reference Capabilities: box (box)class X let v: I32 new create(v': I32) => v = v'
actor Main new create(env: Env) => let a: X ref = X(7) let b: X val = recover X(8) end bar(a) bar(b) fun bar(x: X ref): I32 => x.v() + 1
class X let v: I32 new create(v': I32) => v = v'
actor Main new create(env: Env) => let a: X ref = X(7) let b: X val = recover X(8) end bar(a) bar(b) fun bar(x: X val): I32 => x.v() + 1
ref doesn’t work because a ref (x) can’t alias a val (b)
val Doesn’t work because a val (x) can’t alias a ref (a)
Reference Capabilities: box (box)class X let v: I32 new create(v': I32) => v = v'
actor Main new create(env: Env) => let a: X ref = X(7) let b: X val = recover X(8) end bar(a) bar(b) fun bar(x: X ref): I32 => x.v() + 1
class X let v: I32 new create(v': I32) => v = v'
actor Main new create(env: Env) => let a: X ref = X(7) let b: X val = recover X(8) end bar(a) bar(b) fun bar(x: X val): I32 => x.v() + 1
ref doesn’t work because a ref (x) can’t alias a val (b)
val Doesn’t work because a val (x) can’t alias a ref (a)
class X let v: I32 new create(v': I32) => v = v'
actor Main new create(env: Env) => let a: X ref = X(7) let b: X val = recover X(8) end bar(a) bar(b) fun bar(x: X box): I32 => x.v() + 1
Reference Capabilities: box (box)class X let v: I32 new create(v': I32) => v = v'
actor Main new create(env: Env) => let a: X ref = X(7) let b: X val = recover X(8) end bar(a) bar(b) fun bar(x: X ref): I32 => x.v() + 1
class X let v: I32 new create(v': I32) => v = v'
actor Main new create(env: Env) => let a: X ref = X(7) let b: X val = recover X(8) end bar(a) bar(b) fun bar(x: X val): I32 => x.v() + 1
ref doesn’t work because a ref (x) can’t alias a val (b)
val Doesn’t work because a val (x) can’t alias a ref (a)
class X let v: I32 new create(v': I32) => v = v'
actor Main new create(env: Env) => let a: X ref = X(7) let b: X val = recover X(8) end bar(a) bar(b) fun bar(x: X box): I32 => x.v() + 1
box works because a box (x) can alias a ref (a) or a val (b)
Reference Capabilities: tag (tag)● The Read Rule: If an
actor can read an object then no other actor can modify that object
● The Write Rule: If an actor can modify an object then no other actor can read or modify it
tag reference cannot read or modify an object, but it can be used to send the object messages if the object is an actor, or to compare identity. Other references may read or modify the object as long as they do not violate the Read Rule and the Write Rule.
object
alias1
alias2
alias3
Actor A Actor B
tag
Reference Capabilities: tag (tag)● The Read Rule: If an
actor can read an object then no other actor can modify that object
● The Write Rule: If an actor can modify an object then no other actor can read or modify it
object
alias1
alias2
alias3
Actor A Actor B
tag
Example: alias2 can be a ref because this does not violate the Read Rule or Write Rule
tag reference cannot read or modify an object, but it can be used to send the object messages if the object is an actor, or to compare identity. Other references may read or modify the object as long as they do not violate the Read Rule and the Write Rule.
Reference CapabilitiesReadable → iso, trn, ref, val, box
Writeable → iso, trn, ref
Sendable → iso, val, tag
Objects with sendable reference capabilities can be sent to other actors in messages
Reference Capabilities: Sending A valclass Bar
actor Foo be baz(x: Bar val) => // do something with x
actor Main new create(env: Env) => let f = Foo let b = recover val Bar end f.baz(b)
Reference Capabilities: Sending A valclass Bar
actor Foo be baz(x: Bar val) => // do something with x
actor Main new create(env: Env) => let f = Foo let b = recover val Bar end f.baz(b)
Main
Reference Capabilities: Sending A valclass Bar
actor Foo be baz(x: Bar val) => // do something with x
actor Main new create(env: Env) => let f = Foo let b = recover val Bar end f.baz(b)
Main Foo
foo
Reference Capabilities: Sending A valclass Bar
actor Foo be baz(x: Bar val) => // do something with x
actor Main new create(env: Env) => let f = Foo let b = recover val Bar end f.baz(b)
Main Foo
f
Bar
b
Reference Capabilities: Sending A valclass Bar
actor Foo be baz(x: Bar val) => // do something with x
actor Main new create(env: Env) => let f = Foo let b = recover val Bar end f.baz(b)
Main Foo
f
Bar
b
baz( )
Reference Capabilities: Sending A valclass Bar
actor Foo be baz(x: Bar val) => // do something with x
actor Main new create(env: Env) => let f = Foo let b = recover val Bar end f.baz(b)
Main Foo
f
Bar
b
baz( )
x
Reference Capabilities: Sending A valclass Bar
actor Foo be baz(x: Bar val) => // do something with x
actor Main new create(env: Env) => let f = Foo let b = recover val Bar end f.baz(b)
Main Foo
f
Bar
b x
● The Read Rule: If an actor can read an object then no other actor can modify that object
● The Write Rule: If an actor can modify an object then no other actor can read or modify it
Reference Capabilities: Sending A tagactor Bar
actor Foo be baz(x: Bar tag) => // do something with x
actor Main new create(env: Env) => let f = Foo let b = Bar f.baz(b)
Reference Capabilities: Sending A tagactor Bar
actor Foo be baz(x: Bar tag) => // do something with x
actor Main new create(env: Env) => let f = Foo let b = Bar f.baz(b)
An actor’s default reference capability is tag
Reference Capabilities: Sending A tagactor Bar
actor Foo be baz(x: Bar tag) => // do something with x
actor Main new create(env: Env) => let f = Foo let b = Bar f.baz(b)
Main
Reference Capabilities: Sending A tagactor Bar
actor Foo be baz(x: Bar tag) => // do something with x
actor Main new create(env: Env) => let f = Foo let b = Bar f.baz(b)
Main Foo
foo
Reference Capabilities: Sending A tagactor Bar
actor Foo be baz(x: Bar tag) => // do something with x
actor Main new create(env: Env) => let f = Foo let b = Bar f.baz(b)
Main Foo
f
Bar
b
Reference Capabilities: Sending A tagactor Bar
actor Foo be baz(x: Bar tag) => // do something with x
actor Main new create(env: Env) => let f = Foo let b = Bar f.baz(b)
Main Foo
f
Bar
b
baz( )
Reference Capabilities: Sending A tagactor Bar
actor Foo be baz(x: Bar tag) => // do something with x
actor Main new create(env: Env) => let f = Foo let b = Bar f.baz(b)
Main Foo
f
Bar
b
baz( )
x
Reference Capabilities: Sending A tagactor Bar
actor Foo be baz(x: Bar tag) => // do something with x
actor Main new create(env: Env) => let f = Foo let b = Bar f.baz(b)
Main Foo
f
Bar
b x
● The Read Rule: If an actor can read an object then no other actor can modify that object
● The Write Rule: If an actor can modify an object then no other actor can read or modify it
Reference Capabilities: Sending An isoclass Bar
actor Foo be baz(x: Bar iso) => // do something with x
actor Main new create(env: Env) => let f = Foo let b = recover iso Bar end f.baz(consume b)
Reference Capabilities: Sending An isoclass Bar
actor Foo be baz(x: Bar iso) => // do something with x
actor Main new create(env: Env) => let f = Foo let b = recover iso Bar end f.baz(consume b)
Main
Reference Capabilities: Sending An isoclass Bar
actor Foo be baz(x: Bar iso) => // do something with x
actor Main new create(env: Env) => let f = Foo let b = recover iso Bar end f.baz(consume b)
Main Foo
foo
Reference Capabilities: Sending An isoclass Bar
actor Foo be baz(x: Bar iso) => // do something with x
actor Main new create(env: Env) => let f = Foo let b = recover iso Bar end f.baz(consume b)
Main Foo
f
Bar
b
Reference Capabilities: Sending An isoclass Bar
actor Foo be baz(x: Bar iso) => // do something with x
actor Main new create(env: Env) => let f = Foo let b = recover iso Bar end f.baz(consume b)
Main Foo
f
Bar
b
consume causes b to give up it’s reference
Reference Capabilities: Sending An isoclass Bar
actor Foo be baz(x: Bar iso) => // do something with x
actor Main new create(env: Env) => let f = Foo let b = recover iso Bar end f.baz(consume b)
Main Foo
f
Bar
b
once we consume b, we can no longer use it
Reference Capabilities: Sending An isoclass Bar
actor Foo be baz(x: Bar iso) => // do something with x
actor Main new create(env: Env) => let f = Foo let b = recover iso Bar end f.baz(consume b)
Main Foo
f
Bar
b
baz( )
Reference Capabilities: Sending An isoclass Bar
actor Foo be baz(x: Bar iso) => // do something with x
actor Main new create(env: Env) => let f = Foo let b = recover iso Bar end f.baz(consume b)
Main Foo
f
Bar
b
baz( )
x
Reference Capabilities: Sending An isoclass Bar
actor Foo be baz(x: Bar iso) => // do something with x
actor Main new create(env: Env) => let f = Foo let b = recover iso Bar end f.baz(consume b)
Main Foo
f
Bar
b x
● The Read Rule: If an actor can read an object then no other actor can modify that object
● The Write Rule: If an actor can modify an object then no other actor can read or modify it
No More Data RacesRemember this?
global int a = 0
function inc() { for x in range(0, 1000001) { a = a + 1 }}
function main() { thread thread1 = Thread(inc) thread thread2 = Thread(inc) thread1.run() thread2.run() thread1.join() thread2.join() print(“a = “ + a)}
Expected:
2000000
Actual Run 1:
1987735
Actual Run 2:
1935010
Actual Run 3:
1941217
No More Data RacesRemember this?
global int a = 0
function inc() { for x in range(0, 1000001) { a = a + 1 }}
function main() { thread thread1 = Thread(inc) thread thread2 = Thread(inc) thread1.run() thread2.run() thread1.join() thread2.join() print(“a = “ + a)}
This program violates the Read Rule and Write Rule, because the variable a can be read and modified from multiple threads.
No More Data RacesA first pass at a Pony equivalent
use “collections”
class Counter var v: U64 = 0 fun ref inc() => v = v + 1
actor Inc be doit(c: Counter) => for x in range(0, 100001) do c.inc() end
actor Main new create(env: Env) => let c = Counter Inc.doit(c) Inc.doit(c) env.out.print(c.v.string())
No More Data RacesA first pass at a Pony equivalent
use “collections”
class Counter var v: U64 = 0 fun ref inc() => v = v + 1
actor Inc be doit(c: Counter) => for x in range(0, 100001) do c.inc() end
actor Main new create(env: Env) => let c = Counter Inc.doit(c) Inc.doit(c) env.out.print(c.v.string())
This doesn’t work because the two Inc actors try to read and write to the Counter
No More Data Racesuse “collections”
actor Counter var _count: U64 = 0 be increment() => _count = _count + 1 be print(env: Env) => env.out.print(_count.string())
actor Incrementer new create(counter: Counter, main: Main) => for x in Range(0, 1_000_001) do counter.increment() end main.finished(this)
actor Main let _finished_count = 0 let _counter: Counter = Counter let _env: Env new create(env: Env) => _env = env let inc1 = Incrementer(_counter, this) let inc2 = Incrementer(_counter, this) be finished() => _finished_count = _finished_count + 1 if _finished_count = 2 then _counter.print(env) end
No More Data Racesuse “collections”
actor Counter var _count: U64 = 0 be increment() => _count = _count + 1 be print(env: Env) => env.out.print(_count.string())
actor Incrementer new create(counter: Counter, main: Main) => for x in Range(0, 1_000_001) do counter.increment() end main.finished(this)
actor Main let _finished_count = 0 let _counter: Counter = Counter let _env: Env new create(env: Env) => _env = env let inc1 = Incrementer(_counter, this) let inc2 = Incrementer(_counter, this) be finished() => _finished_count = _finished_count + 1 if _finished_count = 2 then _counter.print(env) end
No More Data Racesuse “collections”
actor Counter var _count: U64 = 0 be increment() => _count = _count + 1 be print(env: Env) => env.out.print(_count.string())
actor Incrementer new create(counter: Counter, main: Main) => for x in Range(0, 1_000_001) do counter.increment() end main.finished(this)
actor Main let _finished_count = 0 let _counter: Counter = Counter let _env: Env new create(env: Env) => _env = env let inc1 = Incrementer(_counter, this) let inc2 = Incrementer(_counter, this) be finished() => _finished_count = _finished_count + 1 if _finished_count = 2 then _counter.print(env) end
No More Data Racesuse “collections”
actor Counter var _count: U64 = 0 be increment() => _count = _count + 1 be print(env: Env) => env.out.print(_count.string())
actor Incrementer new create(counter: Counter, main: Main) => for x in Range(0, 1_000_001) do counter.increment() end main.finished(this)
actor Main let _finished_count = 0 let _counter: Counter = Counter let _env: Env new create(env: Env) => _env = env let inc1 = Incrementer(_counter, this) let inc2 = Incrementer(_counter, this) be finished() => _finished_count = _finished_count + 1 if _finished_count = 2 then _counter.print(env) end
No More Data Racesuse “collections”
actor Counter var _count: U64 = 0 be increment() => _count = _count + 1 be print(env: Env) => env.out.print(_count.string())
actor Incrementer new create(counter: Counter, main: Main) => for x in Range(0, 1_000_001) do counter.increment() end main.finished(this)
actor Main let _finished_count = 0 let _counter: Counter = Counter let _env: Env new create(env: Env) => _env = env let inc1 = Incrementer(_counter, this) let inc2 = Incrementer(_counter, this) be finished() => _finished_count = _finished_count + 1 if _finished_count = 2 then _counter.print(env) end
No More Data Racesuse “collections”
actor Counter var _count: U64 = 0 be increment() => _count = _count + 1 be print(env: Env) => env.out.print(_count.string())
actor Incrementer new create(counter: Counter, main: Main) => for x in Range(0, 1_000_001) do counter.increment() end main.finished(this)
actor Main let _finished_count = 0 let _counter: Counter = Counter let _env: Env new create(env: Env) => _env = env let inc1 = Incrementer(_counter, this) let inc2 = Incrementer(_counter, this) be finished() => _finished_count = _finished_count + 1 if _finished_count = 2 then _counter.print(env) end
No More Data Racesuse “collections”
actor Counter var _count: U64 = 0 be increment() => _count = _count + 1 be print(env: Env) => env.out.print(_count.string())
actor Incrementer new create(counter: Counter, main: Main) => for x in Range(0, 1_000_001) do counter.increment() end main.finished(this)
actor Main let _finished_count = 0 let _counter: Counter = Counter let _env: Env new create(env: Env) => _env = env let inc1 = Incrementer(_counter, this) let inc2 = Incrementer(_counter, this) be finished() => _finished_count = _finished_count + 1 if _finished_count = 2 then _counter.print(env) end
No More Data Racesuse “collections”
actor Counter var _count: U64 = 0 be increment() => _count = _count + 1 be print(env: Env) => env.out.print(_count.string())
actor Incrementer new create(counter: Counter, main: Main) => for x in Range(0, 1_000_001) do counter.increment() end main.finished(this)
actor Main let _finished_count = 0 let _counter: Counter = Counter let _env: Env new create(env: Env) => _env = env let inc1 = Incrementer(_counter, this) let inc2 = Incrementer(_counter, this) be finished() => _finished_count = _finished_count + 1 if _finished_count = 2 then _counter.print(env) end
No More Data Racesuse “collections”
actor Counter var _count: U64 = 0 be increment() => _count = _count + 1 be print(env: Env) => env.out.print(_count.string())
actor Incrementer new create(counter: Counter, main: Main) => for x in Range(0, 1_000_001) do counter.increment() end main.finished(this)
actor Main let _finished_count = 0 let _counter: Counter = Counter let _env: Env new create(env: Env) => _env = env let inc1 = Incrementer(_counter, this) let inc2 = Incrementer(_counter, this) be finished() => _finished_count = _finished_count + 1 if _finished_count = 2 then _counter.print(env) end
2000000
No More Data Racesuse “collections”
actor Counter var _count: U64 = 0 be increment() => _count = _count + 1 be print(env: Env) => env.out.print(_count.string())
actor Incrementer new create(counter: Counter, main: Main) => for x in Range(0, 1_000_001) do counter.increment() end main.finished(this)
actor Main let _finished_count = 0 let _counter: Counter = Counter let _env: Env new create(env: Env) => _env = env let inc1 = Incrementer(_counter, this) let inc2 = Incrementer(_counter, this) be finished() => _finished_count = _finished_count + 1 if _finished_count = 2 then _counter.print(env) end
The Counter actor “protects” the _count data structure
Sendence’s Experience With PonyIt’s nice to catch errors a compile time rather than runtime
Pony is a young language (not even 1.0.0 yet)
Sendence’s Experience With PonyIt’s nice to catch errors a compile time rather than runtime
Pony is a young language (not even 1.0.0 yet)
● limited documentation
Sendence’s Experience With PonyIt’s nice to catch errors a compile time rather than runtime
Pony is a young language (not even 1.0.0 yet)
● limited documentation● things change
Sendence’s Experience With PonyIt’s nice to catch errors a compile time rather than runtime
Pony is a young language (not even 1.0.0 yet)
● limited documentation● things change● there are some sharp edges (compiler bugs, runtime bugs)
Sendence’s Experience With PonyIt’s nice to catch errors a compile time rather than runtime
Pony is a young language (not even 1.0.0 yet)
● limited documentation● things change● there are some sharp edges (compiler bugs, runtime bugs)
“America is all about speed. Hot, nasty, badass speed.” -- Eleanor Roosevelt
PONY
Learn MoreUser Mailing List
● https://pony.groups.io/g/user
Website
● https://www.ponylang.org
IRC
● freenode #ponylang
ContributeDeveloper Mailing List
● https://pony.groups.io/g/dev
Github
● Pony compiler → https://github.com/ponylang/ponyc● RFCs → https://github.com/ponylang/rfcs