Probably Dance

I can program and like games

Recommended Link: Inventing on Principle

https://vimeo.com/36579366

This talk was influental recently but I feel like far more people should follow this advice. The philosophy part is good, but it’s really about the demos.

Read the rest of this entry »

Ideas for a Programming Language Part 3: No Shadow Worlds

This post is inspired by this text by Gilad Bracha. I recommend that you read it before reading this blog post. The idea of Shadow Worlds is that people keep inventing these constructs that are powerful enough that you want to use them as programming languages, but they are not powerful enough to have the features of high level programming languages that make programming enjoyable.

Before reading that blog post I knew that I wanted a macro system for my language. Looking at my old notes I had written down that a macro system is necessary, and that templates are not enough. However I wanted a type safe macro system from modern languages like Nim or Rust. Gilad Bracha’s blog post made me realize that you actually never want macros because they are just another Shadow World. Instead you want to do everything in your high level language.

Read the rest of this entry »

Recommended Link: Deprecating the Observer Pattern

A note about this post: I sometimes feel like I should have a Twitter account just to share random links, but I’d also like something more organized than Twitter. So I think I’ll just post short blog posts here every now and then which are basically just a link and a comment about the link. Let’s start with Deprecating the Observer Pattern:

http://infoscience.epfl.ch/record/176887/files/DeprecatingObservers2012.pdf

One of my favourite papers. After you’ve read it here’s my comments:

Read the rest of this entry »

Ideas for a Programming Language Part 2: A more liberal call stack

One thing that came out of playing around with coroutines is that I eventually realized that callstacks are a bit annoying. It’s one of these things where it’s difficult to convince people because callstacks are equivalent in power to any other form of organizing your program flow. But I think that callstacks constantly force us into solving two puzzles: 1. How to split some sequential, blocking, code up into several smaller pieces of non-blocking code because the function has to return quickly. 2. Where to store an object (or keep track of an object) because it is long-lived but the current scope has to be short-lived.

If you’ve been programming for a while you are really good at solving both of these puzzles because you solve them all the time. Which is another reason for why it’s difficult to convince people that it’s worth looking into alternatives: If you are a programmer today, these don’t seem that complicated to you.

But I want to investigate how much can be gained by looking at different approaches to call stacks. I think the potential gains are huge, because this is such a core piece of programming.

Read the rest of this entry »

Ideas for a Programming Language Part 1: Source Code in Database

My main motivation for wanting to write a programming language is that I believe I can make programmers much more productive. Somewhere in the archives of unfinished blog posts for this website here I have a very long post about what language features and coding practices I think contribute to programmer productivity, (and what harms productivity) but I believe that in the long term the one most important contributor is the quality the tools that we use to program.

And “tools” is a very vague word. It includes everything from source control to text editors to test frameworks to debuggers to refactoring helpers to code completion to compiler warning messages to static analysis to profilers, diff, make and many more categories. All of this surrounding infrastructure that we use around coding actually has a much bigger impact on productivity than which language we pick. Which makes sense because those tools are usually written by someone not directly involved in the language. And if they took the time to write the tool, you bet it will have a big impact on their productivity. So I want to make a language that will have the best tools ever. I think that’s actually not too difficult. It seems that nobody has had that ambition before.

And for that my language will store its source code in a database instead of text files.

Read the rest of this entry »

plalloc: A simple stateful allocator for node based containers

Allocators in C++ are awkward classes. Allocators are usually zero size to make the containers small, and they have no state because that used to be difficult to do in C++. But nowadays we don’t really care about the size of our containers (we care about the size of the content of the containers) and since C++11 we have support for stateful allocators.

The problem I’m trying to solve is that node based containers have bad cache behavior because they allocate all over the place. So I wrote a small allocator which gives out memory from a contiguous block. It speeds up std::map and std::unordered_map. It’s called plalloc because I think this is a pool allocator.

Code is below:

Read the rest of this entry »

Ideas for a Programming Language

I’ve been simmering ideas for a programming language for a while. I’ll probably get around to actually writing one in a year or so. But Jonathan Blow is writing a new language right now and there is some overlap between his ideas and my ideas, so I kinda feel compelled to write about mine.

Since he just had a talk about compile time function evaluation, that will be my first post. But that’s not actually the order in which I want to write about things, so I’ll do a Star Wars move and post part 3 before posting part 1 and 2.

But still this post is a summary of what I will write:

Read the rest of this entry »

Comma Operator RAII Abuse

Here’s a neat little trick that one of my co-workers, Clint Levijoki, discovered. In C++ you often use an RAII wrapper that you place on the stack if you want to be sure that code gets run at a later point. One good example would be std::lock_guard which you use if you want to be sure that a lock gets released in the future, or scoped profiling which you use to stop a timer in the future. For example for this:

std::string foo();
void bar()
{
    std::string baz = foo();
    // do something with baz
}

If you want to profile foo() you’d write it like this:

std::string foo();
void bar()
{
    std::string baz;
    {
        ScopedProfiler profile_foo("foo()");
        baz = foo();
    }
    // do something with baz
}

Which is less pretty and slightly slower. Alternatively you can use the comma operator and do it like this:

std::string foo();
void bar()
{
    std::string baz = (ScopedProfiler("foo()"), foo());
    // do something with baz
}

And this will start a timer before calling foo(), and stop the timer after calling foo(). You could wrap it in a macro to make it more readable. And the benefit is obviously that you don’t have to destroy your function flow when you want to insert RAII objects.

Read the rest of this entry »

Another Opinion on “Almost Always Auto”

Herb Sutter has been promoting his almost always auto style again, and I think it is harmful. I would agree with “almost always auto” in Scala. I disagree with it in C++. And that’s because there is a slight difference in syntax for type inference between the two languages.

Here’s type deduction in Scala:

val inferred = 0
val typed : Int = 1

And here it is in C++

auto inferred = 0;
int typed = 1;

Seems similar, right? But the difference in syntax leads to different long term programmer behavior.

Read the rest of this entry »

The Curious Failure of Functional Programming for Parallel Applications

Long title, but it is interesting how functional programming has mostly failed to gain traction in parallel and concurrent applications. People think that functional programming should become more popular as we do more and more parallel programming, but that doesn’t happen. As an example this blog post made the rounds recently which has this quote in it:

However, the key to multicore programming is controlling mutation. This is why functional languages have been steadily gaining ground in concurrency and parallelism.

Which I would disagree with. Not the controlling mutation part, but the steadily gaining ground part. Let’s look at a few examples:

Read the rest of this entry »

Follow

Get every new post delivered to your Inbox.