# Deriv

Deriv is a basic, command-line symbolic differentiation engine,
supporting reasonably standard mathematical notation for input and
output.

An example interaction:

```
> 2x^2 + 3x
4x + 3
> x^3 - x^2
3x^2 + -2x
```

See [LOG.md](LOG.md) for a log of the development process.

## Building and Running

Deriv is written in Rust and uses Cargo as its build system.  The Rust
toolchain (including Cargo) is most easily installed with
[Rustup](https://rustup.rs/).

Given that you have a toolchain installed, the REPL can be ran with:

```
cargo run --bin repl
```

Alternatively, to only build the project:

```
cargo build
```

To run the test suite:

```
cargo test
```

## Limitations

Deriv currently has several limitations:

- Only the variable "x" is currently supported.
- Exponents must be constant (so e.g. "x^x" is unsupported)
- Expression simplification is quite limited, many output expressions
  may not be fully simplified
- There are no built-in constants like e or π
- Functions such as sine, cosine and natural logarithms are not
  supported
- The input must be UTF-8 Basic Latin / ASCII-compatible text

## License

Deriv is Copyright © Camden Dixie O'Brien, and is available under the
Komorebi 2.0.0 license.  See [LICENSE.md](LICENSE.md) for details.