This is a few-hours attempt at creating an interpreter from scratch for a made-up scripting language. No Virtual Machine, no true compiler, and no optimizations. Just a simple interpreter to parse and execute simple math expressions.
Please don't use for anything you care about. I guarantee this has bugs and terrible error handling.
Called "air" because it sounds a little like the first part of "arithmetic". Also, I will use any excuse to sneak in some Last Airbender reference 🥲
The language itself is just a series of arithmetic expressions that get evaluated down to a single i32 integer. The
purpose was not to create something useful, but to understand parsing and execution.
The script
1 + 1 - (2 + 1 + (3 - 2)) + 12
Evaluates to 10. The expression is evaluated from the innermost parentheses outward. No operator precedence.
See tests/integration.rs for some examples.
+-*/(this rounds the result to an integer)^x(raises to a power)
Only whole numbers are supported. No floating points
air- By itself drops you into a REPL. Type out an expression and hit . Type "exit" to close.air help- opens a simple help screen (probably just this readme)air /path/to/file.air- Evaluates a file if it exists
There is no support for pretty error messages. Just panics if something goes wrong.
If I get done with that, or ever revist the project, I would
- Allow for sets of number
[1, 2, 3]with operators+[1, 2, 3] = 6 - Allow for labels (like variables) and multiple lines
a = 1 + 2 / 3; b = 4^2; b - awould return the last statement - Include increment and decrement operators (++ and --)
That's really it. My next project is to build a rudimentary Virtual Machine and actual Turing Complete toy language, so that's where I would get into scope, function, and all the rest.