Learning to love the unfamiliar

@brian_pearce

LEARNING TO

THE UNFAMILIARLove

with @brian_pearce

@brian_pearce

@brian_pearce

LEARNING TO

THE UNFAMILIARLove

with @brian_pearce

@brian_pearce

Steep learning curve at the beginning

1 in 4 People“

”- State of Rust Survey 2016

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@brian_pearce

def read_file()with open('my_file.txt') as file:

for line in file: process(line)

def process(line)if is_a_pun(line):

tell_a_friend()

Python

@brian_pearce

fn read_file() {let mut data = String::new();let mut f = File::open("my_file.txt").unwrap();f.read_to_string(&mut data).unwrap();for line in data.lines() {

process(line);}

}

fn process(line: &str) {if is_a_pun(line) { tell_a_friend();}

}Rust

@brian_pearce

def read_file(argv)with open('my_file.txt') as file:

for line in file: process(line)

fn read_file() {let mut data = String::new();let mut f = File::open("my_file.txt").unwrap();f.read_to_string(&mut data).unwrap();for line in data.lines() {

process(line);}

}

Python

Rust

@brian_pearce

Introducing:

The Maybe type*star wipe*

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Maybes in the form of:

Option & Result

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enum Option<T> { Some(T), None}

Option:

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Ruby

irb> '7'.to_i

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Ruby

irb> '7'.to_i=> 7

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Ruby

irb> '7'.to_i=> 7

irb> '❤'.to_i

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Ruby

irb> '7'.to_i=> 7

irb> '❤'.to_i=> 0

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Ruby

irb> '7'.to_i=> 7

irb> '❤'.to_i=> 0

irb> '4520000011112222'.to_i=> 4520000011112222

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Ruby

irb> '7'.to_i=> 7

irb> '❤'.to_i=> 0

irb> '4520000011112222'.to_i=> 4520000011112222

irb> '4520not_a_num2'.to_i

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irb> '7'.to_i=> 7

irb> '❤'.to_i=> 0

irb> '4520000011112222'.to_i=> 4520000011112222

irb> '4520not_a_num2'.to_i=> 4520

Ruby

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Rust

rust> '7’.to_digit(...)

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Rust

rust> '7’.to_digit(...)=> Some(7)

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Rust


rust> '❤'.to_digit(...)

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Rust


rust> '❤'.to_digit(...)=> None

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Rust



rust> “4520000011112222”.to_digit(...)=> Some(4520000011112222)

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Rust




rust> “4520not_a_num2”.to_digit(...)

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rust> “4520not_a_num2”.to_digit(...)=> None

Rust

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Rust

rust> '7’.to_digit(...).unwrap()

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Rust

rust> '7’.to_digit(...).unwrap()=> 7

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Rust


rust> '❤'.to_digit(...).unwrap()

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rust> '❤'.to_digit(...).unwrap()=> thread 'main' panicked at 'called `Option::unwrap()` on a `None` value'

Rust

@brian_pearce

puts "Enter a number"num = gets.chomp.to_i

if num.is_a?(Numeric) puts "Great number choice: #{num}"else puts "That wasn't a number"end

Ruby

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Ruby

puts "Enter a number"num = gets.chomp.to_i

if num.is_a?(Numeric) puts "Great number choice: #{num}"else puts "That wasn't a number"end

@brian_pearce

Rust

fn main() {println!("Enter a number");let mut input = String::new();io::stdin().

read_line(&mut num).unwrap();

let int = num.to_digit(10).unwrap();println!("Great number choice: {}", int);

}

@brian_pearce



let maybe = num.to_digit(10);

if maybe.is_some() {let i = maybe.unwrap();println!("Great number choice: {}", i);

} else if maybe.is_none() {println!("That wasn't a number");

};} Rust

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let maybe = num.to_digit(10);

match maybe { Some(n) => {

println!("Great number choice: {}", n);},None => {

println!("That wasn't a number");}

}; Rust

@brian_pearce

thread '<unnamed>' panicked at 'cannot access a TLS value during or after it is destroyed', ../src/libcore/option.rs:330fatal runtime error: Could not unwind stack, error = 5th

read

'<un

name

d>' p

anick

ed at

'can

not a

cces

s a TL

S valu

e dur

ing or

afte

r it i

s des

troye

d', ../

src/

libco

re/o

ption

.rs:33

0fa

tal r

untim

e erro

r: Co

uld no

t unw

ind st

ack,

erro

r = 5

Error Handling

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try { } catch {

}

Java

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begin

rescue

end

Ruby

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try:

expect:

Python

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try!(my_func())

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enum Result<T, E> { Ok(T), Err(E)}

Result

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def read_file(argv)try:

with open('my_file.txt') as file:for line in file: process(line)

except:# Failure

Python

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Rust

fn read_file() {let mut data = String::new();let mut f = File::open("my_file.txt").unwrap()f.read_to_string(&mut data).unwrap();for line in data.lines() {

process(line);};

}

@brian_pearce

Rust

fn read_file() {let mut data = String::new();let mut f = File::open("my_file.txt").unwrap()

f.read_to_string(&mut data).unwrap();for line in data.lines() {

process(line);};

}

@brian_pearce

Rust

fn read_file() -> Result<String, String> {let mut data = String::new();let mut f = try!(File::open("my_file.txt"));


process(line);};

}

@brian_pearce

Rust

fn read_file() -> Result<String, String> {let mut data = String::new();let mut f = try!(

File::open("my_file.txt").map_err(|e| e ));


process(line);};

}

@brian_pearce

fn read_file() -> Result<String, String> {let mut data = String::new();let mut f = try!(

File::open("my_file.txt").map_err(|e| e ));


process(line);};

Ok(“Success”)}

Rust

@brian_pearce

fn my_func() { … }

#[test]fn my_funct_test { … }

Testing

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bash

@brian_pearce

def setup @dir = '/tmp/rb_tests' Dir.mkdir(@dir) unless File.directory?(@dir)end

def teardown FileUtils.rm_r(@dir)end

def test_file_write_one file_name = "#{@dir}/test_one" File.open(file_name, 'w') { |f| f.write "I failed a google code interview" } assert File.exists?(file_name)end

def test_file_write_two file_name = "#{@dir}/test_two" File.open(file_name, 'w') { |f| f.write "had a mixup with the interviewer" } assert File.exists?(file_name)end

def test_file_write_three file_name = "#{@dir}/test_three" File.open(file_name, 'w') { |f| f.write "a mis-understanding of sorts" }end

Ruby

@brian_pearce

fn setup(dir: &String) { let _ = fs::create_dir(dir)}

fn teardown(dir: &String) { let _ = fs::remove_dir(dir);}

#[test]fn test_file_write_one() { let dir_name = format!("/tmp/rs_tests"); let dir = PathBuf::from(dir_name); setup(&dir);

let file_name = format!("{}/{}", dir_name, "test_one"); let file = File::create(&file_name); assert! file.exists(); teardown(&dir);}

#[test]fn test_file_write_two() { ...}

Rust

@brian_pearce

To prevent from accomplishing a

purpose or fulfilling a desire.

“

”

@brian_pearce

For the world was built to develop character, and we

must learn that the setbacks and grieves which

we endure help us in our marching onward.

“

”- Henry Ford

@brian_pearce

LEARNING TO

THE UNFAMILIARLove

with @brian_pearce

Learning to love the unfamiliar

Technology

Transcript of Learning to love the unfamiliar