I started out following Crafting Interpreters, but gradually branched off that until I had almost nothing left in common.
Tech stack: Rust, Cranelift (JIT compilation), LALRPOP (parser).
Original title: "A small programming language where everything is a value" (edited based on comments)
I've only read the first couple paragraphs so far but the idea reminds me of a shareware language I tinkered with years ago in my youth, though I never wrote anything of substance: Euphoria (though nowadays it looks like there's an OpenEuphoria). It had only two fundamental types. (1) The atom: a possibly floating point number, and (2) the sequence: a list of zero or more atoms and sequences. Strings in particular are just sequences of codepoint atoms.
It had a notion of "type"s which were functions that returned a boolean 1 only if given a valid value for the type being defined. I presume it used byte packing and copy-on-write or whatever for its speed boasts.
I've got a hobby language that combines this with compile time code execution to get static typing - or I should say that's the plan, it's really just a tokenizer and half of a parser at the moment - I should get back to it.
The cool side effect of this is that properly validating dynamic values at runtime is just as ergonomic as casting - you just call the type function on the value at runtime.
So basucally everything is var?
There are two ways to define a variable binding:
x = 1; // declares x as immutable
var y = 2; // declares y as mutable
[1] https://github.com/FransFaase/IParse/?tab=readme-ov-file#mar...
discarded1023•1h ago
Things of course become a lot more fun with concurrency.
Now if you want a language where all the data thingies are immutable values and effects are somewhat tamed but types aren't too fancy etc. try looking at Milner's classic Standard ML (late 1970s, effectively frozen in 1997). It has all you dream of and more.
In any case keep having fun and don't get too bogged in syntax.
jcparkyn•54m ago
> Standard ML [...] It has all you dream of and more
The main thing here that's missing in Standard ML (and most other functional languages) is the "mutable" part of "mutable value semantics" - i.e., the ability to modify variables in-place (even nested parts of complex structures) without affecting copies. This is different from "shadowing" a binding with a different value, since it works in loops etc.
doug-moen•32m ago