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It’s finally here – our mini-program to calculate factorials, featuring a while loop and mutable variables, is working! You can find the source code at codeberg.org/andybalaam/milk and more of my stuff at artificialworlds.net

Our while loop is close … first we need to be actually calculate new values for variables when we see a += or *= operator. You can find the source code at codeberg.org/andybalaam/milk and more of my stuff at artificialworlds.net

We’ve been putting off creating a Unit type, (), and we need our type checker to be OK with += etc. We are getting excitingly close to having a working while loop! You can find the source code at codeberg.org/andybalaam/milk and more of my stuff at ar…

This is the first time we are handling modifying variables, so our current “assignment” parser, which looks for a let keyword is no help – we need a new bit of parsing for modification statements. You can find the source code at codeberg.org/andybalaa…

I am standing for re-election to the Matrix Governing Board (see the election announcement). The Governing Board advises and oversees the work of the Matrix Foundation. I will stand as an Individual Member again, not representing a company or project. …

Testing that something is not there can be unreliable Today I am writing a test that something does not happen, like this: Given that the A setting is "off" When I start the app Then the warning about A being on IS NOT displayed It’s quite…

The little real-world snippet we are trying to get working includes a while loop – let’s try to get it to parse. For now, only if the actual loop body is empty. You can find the source code at codeberg.org/andybalaam/milk and more of my stuff at artif…

Now we’re going to try and get a little code snippet that calculates factorials to work. First up: lexing the <= sign! You can find the source code at codeberg.org/andybalaam/milk and more of my stuff at artificialworlds.net

Now that we have the types we calculated in our syntax tree, use them to stop faking it in error messages – replace a hard-coded “integer” with the actual type of the expression we are talking about. You can find the source code at codeberg.org/andyba…

The type checker is passing our unit tests, but it’s stopping our language from actually working. Time to fill in the gaps. You can find the source code at codeberg.org/andybalaam/milk and more of my stuff at artificialworlds.net

We have a plan for what error message we should get when we try to write code like let x: i32 = 3.0;. Let’s try to make it a reality! You can find the source code at codeberg.org/andybalaam/milk and more of my stuff at artificialworlds.net

We’re still on a mission to do some type-checking, and our plan is to allow writing let x: i32 = 3.0;, then produce a type error because 3.0 is not an integer that can be stored in an i32. The last piece of the puzzle is to be able to handle the 3.0 bi…

We left our parser in an awful mess after the last video, so we’re going to tidy it up a bit and make it easier to understand. You can find the source code at codeberg.org/andybalaam/milk and more of my stuff at artificialworlds.net

Finally, we are going to execute a real piece of code that actually looks like a programming language! We are setting a variable to a value, and then using that variable later on… You can find the source code at codeberg.org/andybalaam/milk and more…

We’ve built a toy parser, but it’s not going to last us. We need to make it a bit more proper. Specifically, we need to be able to look ahead, and then backtrack. You can find the source code at codeberg.org/andybalaam/milk and more of my stuff at art…

Last time we lexed an assignment statement. This time: parsing it, so we’re ready to execute it! You can find the source code at codeberg.org/andybalaam/milk and more of my stuff at artificialworlds.net

We’re ready to lex a proper statement: specifically a “let” statement that will give a variable its value. You can find the source code at codeberg.org/andybalaam/milk and more of my stuff at artificialworlds.net

Our parser kinda works, but it needs some work to be less terrible. We’ve realised we did a few things in awkward or wrong ways, so let’s fix them before they get out of hand. You can find the source code at codeberg.org/andybalaam/milk and more of my…

Now that we can parse things, let’s evaluate them. By the end of this, we should be able to use our little language as a mini-calculator (only for adding up so far though). You can find the source code at codeberg.org/andybalaam/milk and more of my st…

We’re finally ready to parse things! Our lexer can do almost enough to allow us to handle “3 + 5”, so we’ll make that ready, and then parse that expression into a syntax tree. You can find the source code at codeberg.org/andybalaam/milk and more of my…

Our lex function returns an iterator, but in the implementation we were faking it. Let’s do it properly. You can find the source code at codeberg.org/andybalaam/milk and more of my stuff at artificialworlds.net

More of the very basic structure of our interpreter: making the error messages from the lexer point at the exact line of code, in a pretty way. You can find the source code at codeberg.org/andybalaam/milk and more of my stuff at artificialworlds.net

Continuing writing our mini-rust in Rust. Figuring out how to throw an error when lexing goes wrong. You can find the source code at codeberg.org/andybalaam/milk and more of my stuff at artificialworlds.net

I just evaluated and installed software for providing comments and statistics for this blog. Here are my experiences of the deployment process: A Python comment system. Uses one of the 17 outdated installer/packaging systems for Python (none of which…

Wrapping a C function with safe Rust code. Series: Language basics, More syntax, Traits and generics, Building applications, Concurrency and parallelism, Trait objects, Async, Unsafe This section (Async): 42: Why unsafe?, 43: Meaning of unsafe, 44: Un…