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WebAssembly
Jay Phelps | @_jayphelps
The
Revolutionhas begun

WebAssembly will change the way
we think of "web apps"

Senior Software Engineer |
@_jayphelps
Jay Phelps

So...what is WebAssembly? aka wasm

Efﬁcient, low-level bytecode for the Web

Fast to load and execute

0x6a01101010

Intended as a compilation target

int factorial(int n) {
if (n == 0) {
return 1;
} else {
return n * factorial(n - 1);
}
}

int factorial(int n) {
if (n == 0) {
return 1;
} else {
return n * factorial(n - 1);
}
}
00 61 73 6D 01 00 00 00 01
86 80 80 80 00 01 60 01 7F
01 7F 03 82 80 80 80 00 01
00 06 81 80 80 80 00 00 0A
9D 80 80 80 00 01 97 80 80
80 00 00 20 00 41 00 46 04
40 41 01 0F 0B 20 00 41 01
6B 10 00 20 00 6C 0B

Safe and portable
just like JavaScript is

Is it going to kill JavaScript?

Nope!says browser vendors
*

*well...maybe...some day...a long time from now
(my own opinion)

Will we compile JavaScript to WebAssembly?

JavaScript is an extremely dynamic language

Compiling JavaScript to WebAssembly would run slower
What about a something JavaScript-like?

AssemblyScript, TurboScript, ThinScript, etc

class Coordinates {
x: i64;
y: i64;
z: i64;
constructor(x: i64, y: i64, z: i64) {
this.x = x;
this.y = y;
this.z = z;
}
}
export function example() {
let position = new Coordinates(10, 20, 30);
// later
delete position;
}

WebAssembly is still missing things
for broad adoption

v1 MVP is best suited for languages like
C/C++ and Rust

But other languages soon!
Things like Java, OCaml, and even brand new ones

type schoolPerson = Teacher | Director | Student(string);
let greeting = (stranger) =>
switch stranger {
| Teacher => "Hey professor!"
| Director => "Hello director."
| Student("Richard") => "Still here Ricky?"
| Student(anyOtherName) => "Hey, " ++ anyOtherName ++ "."
};

When should I target WebAssembly right now?

Heavily CPU-bound number computations

Games
Physics Simulation
Encryption
Compression
Video Decoding
Audio Mixing
Language Detection

Jay Phelps | @_jayphelpshttps://goo.gl/yvV92X
Demo

Other use cases just around the corner

You'll likely consume compiled
WebAssembly libraries even sooner

What was that binary stuff?

00 61 73 6D 01 00 00 00 01
86 80 80 80 00 01 60 01 7F
01 7F 03 82 80 80 80 00 01
00 06 81 80 80 80 00 00 0A
9D 80 80 80 00 01 97 80 80
80 00 00 20 00 41 00 46 04
40 41 01 0F 0B 20 00 41 01
6B 10 00 20 00 6C 0B

03 82 80 80 80 0
81 80 80 80 00 0
80 80 00 01 97 8
00 20 00 41 00 4

Binary can be a little intimidating

Protip: don't worry about it
(unless of course, you want to)

Textual representation to the rescue!

(func $factorial (param $n i32) (result i32)
get_local $n
i32.const 0
i32.eq
if $if0
i32.const 1
return
end $if0
get_local $n
i32.const 1
i32.sub
call $factorial
get_local $n
i32.mul
)

WebAssembly is a stack machine language

stack machine: instructions on a stack

i32.add 0x6a
opcode
01101010
mnemonic

stack
i32.const 1
i32.const 2
i32.add

i32.const 1
i32.const 2
i32.add
i32.const 1
stack
1

i32.const 1
i32.const 2
i32.add
i32.const 2
stack
2
1

i32.const 1
i32.const 2
i32.addi32.add
stack
1
2

i32.const 1
i32.const 2
i32.add
stack
3
i32.add

call $log
i32.const 1
i32.const 2
i32.add

Compilers usually apply optimizations
real-world output is often less understandable to humans

i32.const 1
i32.const 2
i32.add
call $log

i32.const 3
call $log

Most tooling supports an Abstract Syntax Tree (AST)
still compiled and evaluated as a stack machine

(call $log
(i32.add
(i32.const 1)
(i32.const 2)
)
)

(call $log
(i32.add
(i32.const 1)
(i32.const 2)
)
)
s-expressions
Yep, looks like Lisp

Source map support is coming

What about memory on the heap?

A linear memory is a contiguous, byte-
addressable range of memory

Accessed with instructions like
i32.load and i32.store

0 1 2 3 4 5 6 7 8 9 10

0 1 2 3 4 5 6 7 8 9 10
1 byte

0 1 2 3 4 5 6 7 8 9 10
w a s m

0 1 2 3 4 5 6 7 8 9 10
119 97 115 109

How do I get started?

https://mbebenita.github.io/WasmExplorer/

https://github.com/WebAssembly/wabt

https://github.com/WebAssembly/binaryen

$ emcc main.c -s WASM=1 -o app.html

webassembly.org

Webpack is adding support (!!!)
They received a $125,000 grant from MOSS

Imagine a cpp-loader / rust-loader

What's missing?

Direct access to Web APIs
You have call into JavaScript, right now

Garbage collection
also necessary for better interop with JavaScript and WebIDL

Multi-threading

Browser support?

The WebAssembly Revolution Has Begun

The revolution is just beginning

Questions?
@_jayphelps

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The WebAssembly Revolution Has Begun

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