Tools for evaluation of CalcScript expressions.

This crate provides tools to help evaluate CalcScript code. It is split into two main submodules, funcs and symbolic, which provide implementations of useful mathematical functions, and symbolic evaluation respectively. Currently, symbolic manipulation is limited to simplification, but this will be extended in the future.

Usage

Function implementations

The funcs module statically implements a variety of algorithms and functions used in CalcScript, such as trigonometric, combinatoric, and probability distribution functions. The functions use the arbitrary-precision types from the rug crate to ensure that they can handle high-precision calculations.

To use a function, import it from the funcs module and call it with the appropriate arguments. You may need to convert the arguments to the expected rug these conversions.

use cas_compute::funcs::miscellaneous::{Factorial, Gamma};
use cas_compute::numerical::value::Value;
use cas_compute::primitive::{complex, float};

let z = complex((8.0, 0.0)); // 8 + 0i
// let z = complex(8); // equivalent
let gamma_z = Gamma::eval_static(z);

// Factorial supports floats, so it returns a `Value` for it to support both
// floating-point and integer return types
let factorial_i = Factorial::eval_static(float(7)); // 7! = 5040

// the effect is that we need to wrap `gamma_z` in a `Value` to compare it with
// factorial_i, or extract a `rug::Complex` from `factorial_i` to compare it
// with `gamma_z`
//
// this will most likely be improved in the future

assert_eq!(Value::Complex(gamma_z).coerce_integer(), factorial_i);

Numerical helpers

The numerical module provides helpers used in other cas-rs libraries, mainly the Value type and Value formatting. Since version 0.2.0, it no longer provides numerical evaluation; instead, that functionality was moved to cas-vm as CalcScript became a compiled language.

Simplification

The symbolic module currently provides simplify to simplify expressions symbolically.

See its module-level documentation for more information.

use cas_compute::primitive::int;
use cas_compute::symbolic::{expr::{SymExpr, Primary}, simplify};
use cas_parser::parser::{ast::Expr, Parser};

let mut parser = Parser::new("x + x + x");
let ast_expr = parser.try_parse_full::<Expr>().unwrap();

let simplified = simplify(&ast_expr.into());

// `x + x + x = 3x`
assert_eq!(simplified, SymExpr::Mul(vec![
    SymExpr::Primary(Primary::Integer(int(3))),
    SymExpr::Primary(Primary::Symbol("x".to_string())),
]));

Feature flags

• mysql: Derives mysql_common traits for various types provided by this crate.
• serde: Derives Serialize and Deserialize for various types provided by this crate.