# SCL: Simple CAS Language

## Usage

```bash
git clone https://git.signorovitch.org/jacob/scl && cd scl
make release    # Build.
./scl           # Run.
```

If you wish to run tests, make sure to run `git clone --recurse-submodules` to
include the [Unity](https://github.com/ThrowTheSwitch/Unity) test framework.

## Current State

- [x] Floating-point numbers
- [x] Negative numbers
- [x] Basic binary infix operators; `+`, `-`, `*`, `/`
- [x] The same as conventional functions; `sum()`, `sub()`, `mul()`, `div()`
- [x] Arbitrary length functions
- [ ] User-defined variables
- [ ] Control flow
- [ ] User-defined functions

## Syntax (Planned)

As one would expect, you can evaluate simple infix expressions:

```scl
> 1 + 1
= 2
```

You can also define your own functions:

```scl
> f(x) = 2x
> f(2)
= 4
```

Symbolic algebra is done in the following manner:

```scl
> f(x) = x^4
> diff(f, x:sym, 2)
= 12x^2
```

SCL will dynamically decide on types, but you can state them explicitly as
well:

```scl
> f(x:int) = 2x
> f(2.2)
! f(x:int): x must be of type int.
```

Variables can be defined, with several attributes:

```scl
> a = 1             // Interpret type automatically.
> b:int = 1         // Must be int.
> c:const:int = 1   // Constant: value can never change.
> x:sym             // Treated symbolicaly.
```