# mers ![build status](https://github.com/Dummi26/mers/actions/workflows/rust.yml/badge.svg)

Mers is an experimental programming language inspired by high-level and scripting languages, but with error handling inspired by rust.

## Why mers?

mers has...

- the type-safety of statically typed languages
  + mers will not crash unless you `exit()` with a nonzero exit code or write flawed assumptions using the builtin `.assume*()` functions (Rust's `unwrap` or `expect`)
- the flexibility of dynamically typed languages
  + `x := if condition() { "my string" } else { 12 } // <- this is valid`
- "correctness" (this is subjective and I'll be happy to discuss some of these decisions with people)
  + there is no `null` / `nil`
  + all references are explicit: if you pass a list by value, the original list will *never* be modified in any way.
  + errors are normal values! (no special treatment)
- a flexible type system to easily represent these errors and any complex structure including recursive types:
  + nothing: `[]` (an empty tuple)
  + a string: `string`
  + two strings: `[string string]` (a tuple)
  + many strings: `[string ...]` (a list)
  + Either a string or nothing (Rust's `Option<String>`): `string/[]`
  + Either an int or an error: (Rust's `Result<isize, String>`): `int/string` (better: `int/Err(string)`)
- compile-time execution through (explicit) macro syntax: `!(mers {<code>})` or `!(mers "file")`

## How mers?

There are prebuilt binaries in `build_scripts/`.

Mers is written in Rust. If you have `cargo`, you can also use the build script in `build_scripts/` to build it yourself.

Now, create a new text file (or choose one from the examples) and run it: `mers <file>`.

## Known Issues (only major ones)

### Multithreading

If a function is called from two threads, all local variables of that function are shared.
This doesn't affect builtin functions, and since functions usually don't take long to execute,
the change of anyone encountering this is low, but it's something to be aware of.
It's a simple fix in theory, but a lot of work to implement, which is why the bug isn't fixed yet.

## Docs

[intro](docs/intro.md)

[syntax cheat sheet](docs/syntax_cheat_sheet.md)

[builtins](docs/builtins.md)

[statements](docs/statements.md)