Today I'll be speaking, mentoring, then judging at Keewi's Hack Day event.

Over a decade ago I joined a group of "hackers" in developing an open source ultra-secure UNIX operating system called OpenBSD. As the most secure OS in the world, it was designed to keep out hackers, as in crackers, those seeking unauthorized access to computer systems. But we were also hackers, a type of "artisanal" programmer. OpenBSD hackers are spread across the world and they gather themselves together periodically into one place to be super productive on a common goal over the course of several days. OpenBSD invented the hackathon, even coining the word itself.

I attended my first hackathon back when I was still in school, which I graduated from over 10 years ago. It was organized by our university's open source club, the only extracurricular activity I was involved in. We got permission to use one of the classrooms overnight and even got funding to buy a couple pizzas and pop. That was it. There were no corporate sponsors. There were no spectators watching us code except for our confused girlfriends. There were no headhunters or suits looking for geeks they could make use of. And there was no prize money because we were just there to see what hacks we could pull off in a night and then show each other.

Nowadays, hackathons are more and more common and are seen by corporations as something they can take advantage of.

A Quiet American in a Quiet Vietnam

About two weeks after I first arrived in Saigon, it began: Tet. What a horrible mistake, being in Vietnam right at that time! Tet, being the single Vietnamese holiday that is equivalent to Thanksgiving, Christmas, and New Year in one long week that often stretches to a month for many students as well as laborours. While pre-Tet is a time of high commercial activity, it all comes to a full stop at midnight of the Lunar New Year. Vietnamese people go home. And for Saigon's 10 million or so population, this mostly means going back to places far from metropolitan Ho Chi Minh City. Vietnamese cities are full of economic migrants, young people coming as students or looking for jobs so they can earn money to send home. And Tet is the time of the year, for most economic migrants it's the one and only time of the year, when they return home to their families.

As a company or factory, you don't expect anyone to work during the days of Tet. It doesn't matter if you're a foreign company with orders from foreign countries that need to be filled, by customers that neither know nor care that a "Tet" is happening. If you're lucky, your employees will come back to work after a week, after you've paid them a "13th month" Tet bonus, often equivalent to one month's salary.

On Saturday December 8th, Ho Chi Minh City along with 200 other cities around the world celebrated a global Code Retreat.

What is a code retreat?

Like a meditation retreat, a code retreat is a time set aside to step out of the daily life and routine in order to get deep into practice. It's a full work day, and everyone attending is giving up their Saturday to do what they are probably paid to do from Monday to Friday. That's dedication to the craft. Not so many people came, partly due to poor advertising.

The code retreat was open to anyone but all attendees were fellow programmers, those with some experience already but who want to improve themselves. Besides myself, there was a motley crew of foreigners - an organizer from Japan, a local software tycoon originally from Spain, a Czech developer. Otherwise, all Vietnamese, including startup developers, university faculty, students, and corporate workers.

The venue was ERC Vietnam, the Singaporean MBA school who, along with two other Singaporean schools in Vietnam, is rumored to have lost its operating license from the Ministry of Education which would force it to close. However, the school was still open as usual. A Toastmasters club was also meeting in the room across the hall. There were scheduled outings for students posted in the elevators to be held at local bars and restaurants.

The coding

There were six sessions lasting about an hour each throughout the day and each session was the same both in format and content. The format was:

15 minutes - pair up with another programmer and discuss the strategy for writing the program - choose a language, maybe a framework, discuss data structures and algorithms
15 minutes - one person "drives" the keyboard, the other "navigates" - pair programming (an extreme programming methodology) where two developers use a single laptop to collaboratively develop software
15 minutes - switch up driver and navigator, although often times only a single person was familiar with the text editor or developing environment or even language and API (some languages heavily depend on libraries and APIs to do simple tasks which are difficult to do in the core language alone)
15 minutes - retrospective and break - we wrote down our learnings on sticky notes and collected them for each other to read and at the end of the day we had a whole day retrospective

What were we writing?

We were implementing Conway's Game of Life. Each pair (each session we picked new partners) wrote the game six times throughout the day, erasing the code they had written at the end of each session. The goal was not to write the game of life, but to get better at writing code by writing the same code over and over, by developing the same software over and over.

Halfway through the day some rules started to be added. First, we had to use TDD (test driven development) methodology (which some people didn't realize was feasible in JavaScript), then OOP (what if someone had chosen Scheme or some other functional language?). This was to encourage us to try new techniques and learn them from each other.

I was an outlier in that I wanted to use languages like Python, JavaScript, or even PHP instead of .Net framework languages. Instead of a massive IDE I was using Vim. In the end, in each session where it was up to me I chose Javascript. There was no need to build a new project from a template and then compile executables before running them. Just open a text file, save as html, and use Chrome as a development environment.

Later, more rules were imposed:
No if statements.
No loops (for, while, etc.).
No functions longer than a few lines (maybe 3 or 5 statements max).

We were encouraged to pick one rule and try to work within its constraints. I decided to apply all the rules!

These rules would be easy to abide by using a functional programming language but they're not impossible to follow in Python or Javascript either. But to replace loops using recursion, one thing I found was that nobody remembered how to write recursive functions and most people didn't even want to try as it was hurting their heads.

After the day was over, I took a look at underscore.js, a utility library for JavaScript which makes functional-like programming in JavaScript much easier.

Here's what I came up with.

<script src="underscore.js"></script>
<script>
 
// row and col are indices into 2d array 'grid', either 'today' or 'tomorrow'
function value(grid, row, col) { return (_.isUndefined(grid[row]) || _.isUndefined(grid[row][col])) ? 0 : grid[row][col]; }
function count_neighbors(grid, row, col) {
    return value(grid, row-1, col-1) + value(grid, row-1, col) + value(grid, row-1, col+1) +
           value(grid, row  , col-1) +                           value(grid, row  , col+1) +
           value(grid, row+1, col-1) + value(grid, row+1, col) + value(grid, row+1, col+1);
}
function next_state_if(neighbors, state) { return (neighbors == 3) ? 1 : ((neighbors == 2) ? state : 0); }
function next_state(grid, row, col) { return next_state_if(count_neighbors(grid, row, col), grid[row][col]); }
function calculate_tomorrow(today, tomorrow) {
    _.each(today, function (foo, row) {
        _.each(this.today[row], function (foo, col) { this.tomorrow[row][col] = next_state(this.today, row, col); }, this);
    }, {today: today, tomorrow: tomorrow});
}
 
// helpers
function copy2d(ary2d) { return _.map(ary2d, function (list) { return list.slice(); }); }
function print_r(ary2d) { console.log(_.map(ary2d, function (list) { return list.join(''); }).join('\n')); }
function random_init() { return _.map(_.range(30), function (list) { return _.map(_.range(30), function (list) { return _.random(1); }); }); }
 
// demo main loop
var today = random_init();
var tomorrow = random_init();
print_r(today);
setInterval(function(){
    calculate_tomorrow(today, tomorrow);
    print_r(tomorrow);
    today = copy2d(tomorrow);
}, 400);
</script>

Let's set some ground rules: Street food must be eaten on the sidewalk without the option of eating indoors, as many "proper" restaurants also have outdoor seating, even though such "al fresco" appropriations of the street are actually illegal and subject to periodic police inspections where illegally placed plastic chairs and tables are confiscated. For Vietnamese small business owners who don't even rent space inside any buildings, their whole business depends on police not cracking down on them. Perhaps a better solution would be a non-corrupt (haha) registration and hygiene inspection process for street food vendors, then the government could get some tax income, the business owners would have some stability, and the consumers would get some level of food safety. But for now, let's get back to reality.

1. Banh Xeo - often translated as Vietnamese pancakes or Vietnamese crepes. Like pancakes or crepes, a batter is poured into a circular pan to crispen a thin round layer of this "cake" which has toppings like shrimp and pork, bean sprouts, and sometimes mushrooms (but not so much in the street). Banh Xeo Mien Trung is a smaller version. You can try this on Phan Ke Binh Street (near DeciBel) and Ung Van Khiem Street near D2 in Binh Thanh District.

2. Banh Mi Thit - the Vietnamese submarine sandwich / roll. Next to pho, this is probably the most famous Vietnamese dish outside of Vietnam. A French bread roll spread with pate (both foods from the French colonial era) stuffed with some kind of meat, julienned carrots and pickled daikon, cilantro - and some fresh and extremely spicy chili peppers if you don't remember to ask them "khong ot". Vo Van Tan near Cach Mang Thang 8 in District 3 has a popular shop to get some takeaway banh mi thit. Also try Banh Mi Heo Quay, pork with delicious -crispy- fat and skin attached, available on Ngo Tat To Street in Binh Thanh District.

3. Mi Hoanh Thanh - Chinese Won Ton Ramen Noodle Cart. Also seemingly referred to as "van than" in the North Vietnamese dialect. "Mi" refers to ramen noodles and if you think ramen means cheap instant noodles then you need to get schooled. Often these will be served in fancy wooden noodle carts which you can also sit at. The noodles should be fresh, not instant industrially dried noodles. Hoanh Thanh are won ton noodle dumplings. Also try Mi Xa Xiu - "char siu" in Chinese or cha-shu in Japanese. Try it at the corner of Xo Viet Nghe Tinh right after the Thi Nghe Bridge.

4. Banh Khot - Banh Khot is similar to Banh Xeo but thicker with a much smaller diameter. Too similar for me to distinguish is another dish called Banh Canh, not to be confused with the similarly pronounced Banh Canh noodle dish. Like Banh Xeo, after the batter and toppings are fired in their clay vessels they are wrapped by your hands in lettuce or mustard greens and rice paper, topped with fresh herbs, and then dipped in fish sauce.

5. Hu Tiu (Nam Vang), Hu Tiu Go - Hu Tiu (or Hu Tieu) is a kind of noodle. Hu Tiu Nam Vang refers to a version of this noodle dish, which can be eaten in soup or "dry", which should be Khmer - Nam Vang is an old Vietnamese word for Phnom Penh. Hu Tiu Go isn't a flavor of Hu Tiu. Rather it refers to the way it is sold. Go means to knock, and a seller of Hu Tiu Go will push his cart down the street while knocking on wood to let people know he's coming.

6. Banh Trang Tron - A favorite after school snack of Vietnamese girls. A trail mix of rice paper, herbs, chili chopped up and mixed with dried beef or quail eggs and served in a plastic bag with two small sticks to be used like chopsticks.

7. Com Tam - broken rice, a traditional South Vietnamese breakfast as opposed to pho in the North. Using the broken grains of rice served with BBQ pork (suon), sunny-side up egg (op-la), (bi), (cha), and with fish sauce (nuoc mam) dripped over to taste.

8. Xoi - Sticky rice. Can be served with separated chicken as easily as with ripe mango or other sweets. A favorite of mine is Xoi Khuc.

9. Bot Chien - What look like mochi cubes are thrown in a wok and fried with an egg or two into an omelette with fried cubes of... what exactly? Photo attached.

10. Banh Cuon - Kind of like a giant round noodle. Banh in Vietnamese can mean many things although it's often translated to cake. It can also mean bread and sometimes the noodle in a noodle dish. Banh Cuon is some kind of batter steamed in a giant circle until it's hard and noodley then topped with something like ground beef (or seafood or chicke and mushrooms if you want to get fancy). Then you add some "cha", herbs, and bean sprouts and pour on the nuoc mam and put it all into your mouth.

11. Bo La Lot - This one almost killed me. Street food is all fun and games until you are vomiting out both ends of your body for 24 hours. This dish of mystery beef wrapped in "lot" leaves and then cooked over coals, then wrapped in rice paper or greens and topped with thinly sliced papaya or unripe bananas and other leaves, can be quite tasty. But take it from me: avoid buying it from the sidewalk sellers on Ton Duc Thang Street right at the beginning of Le Thanh Ton Street.
Drink

Refreshments

Nuoc Mia - The quintessential street drink. Sugar cane juice made by running sticks of sugar cane through a press. When I first started drinking this it was availale for 2000 VND/glass but now it's no less than 4000 VND, which still comes out to less than 20 cents.

Sinh To - fruit smoothies. Strawberry, tomato, avacado, custard apple, banana, mango, etc. Go to the Hang Xanh Roundabout (aka The Circle of Death) after midnight if you're bored and thirsty.

Trai Dua - This is not even street food, it's jungle food. In the Mekong Delta, in provinces like Ben Tre, this magical fruit literally grows on trees. Coconuts can be drunk anywhere as long as you have a way to crack them open.

Tra Chanh - This is a street drink but it's not a Saigon street drink. Next time I will write about drinking this lemon tea on the streets of Hanoi.