Survey: How many lines of code can you clearly visualize? | Hacker News Reader

Survey: How many lines of code can you clearly visualize?

2 pointspalish8 comments

I asked a productive coworker if he always kept his code "in his head" while he worked. He replied, "When I was younger, I could keep three thousand lines of assembly code in my head. I could go to the exact line of any feature instantly."

He single-handedly wrote several games for major publishers (Electronic Arts and others) when games were becoming popular.

So, setting aside for a moment that number-of-lines-of-code is a bad measurement, how many lines can you clearly picture in your head? Just throw out a rough estimate.

View on HN

You don't hold line of codes in your head, you hold a map of interconnected concepts, in various zoom levels.

Zoom enough and you'll see lines of codes, but most of the time you just manipulate these larger blocks.

As you build up your language for your specific problem and your tools of expressions evolve, each concept maps significantly more behavior, logic & power.

A good example for this can be seen in professional chess players playing blind-folded, they don't memorize the location of all 32 pieces on the board, they memorize the different formation groups, their mental vocabulary has increased to include groups of chess pieces in specific arrangements. If you ask them to remember randomly placed chess pieces they fail just like the average person.

As long as I work on one problem, I remember all methods I have written and what they do. I also keep the architecture in my head and the approach I have chosen to solve the problem. This works fine as long as I am not interrupted.

I cannot recommend trying to hold too much in your head at once. I has a bad effect on your creativity. Free your mind instead to have all necessary resources available to find the best solution for the current problem.

It is also an achievement to break down large chunks of work into small parts and solve only the small parts.

In this perspective it is absolutely useless to keep code in the head. It is written in the editor right in front of your eyes anyway.

I think "picture in your head" and "know well enough to go to the exact place of any feature" are not the same thing. I can picture in my head a very small number of lines of the code I usually write. Less than five, at any rate. But maybe I misunderstand what you're asking.

Unfortunately, the question can't be very specific. I've always been fascinated by people who can clearly picture things in their mind.

For example, one time Woz accidentally deleted ColorMath, a program that Jobs was going to show off at a trade show the very next day. Deleting it wasn't a setback, because the code for ColorMath was "in his head". Presumably he was able to sit down the next morning and rewrite ColorMath extremely quickly.

It seems like an artist can only be good if he can clearly visualize large amounts of detail before touching a brush. Perhaps the best artists are ones who can visualize the most detail.

In warfare, the best generals are the ones who can keep track of every single nuance of the battlefield simultaneously.

The mind's eye seems to be important in every creative profession.

So this modest survey is an attempt toward figuring out what makes an artisan excellent.

He was lying, no one who isn't a savant can remember 3 thousand lines of code to the exact line. More likely he remember key lines where particular features began.

Ever heard of Kim Peek (http://en.wikipedia.org/wiki/Kim_Peek)? While he doesn't memorize code, he remembers other equally impressive things.

There's an interesting documentary about him: http://www.youtube.com/watch?v=k2T45r5G3kA

That's fascinating. Thanks.

I wonder what kind of program he'd write, if he decided to learn programming.

I think a better gauge is the number of features that you can keep in your head, rather than the number of lines of code. (LOC doesn't always directly correlate with complexity, anyway.) I'd say I can usually hold about 50% of the features of the projects I usually work on in my day job without having to do a "context switch". Usually, it's oriented around clear lines in the code -- for example, the latest project I worked on had a program written for a handheld computer with the .NET compact framework, a website written with MonoRail and ExtJS, and a large data migration system. If I was working on the website, I could typically answer questions quickly about most of the common features in the handheld application. However, when asked about the more complex aspects, it took me a few minutes to "page swap" the handheld code into my brain. :)

Reply on news.ycombinator.com