#math #expression #evaluation #parsing-tools

no-std evaluatorrs

Tools for runtime evaluation of mathematical expressions

1 unstable release

0.0.1 Sep 14, 2023

#6 in #parsing-tools

MIT/Apache

91KB
2K SLoC

This library provides ways to evaluate mathematical expressions at runtime.

Feature switches

  • std (default): enables use of std library
  • libm: enables use of mathematical functions from libm, useful for no_std crates and non-standard functions

Example 1

use evaluatorrs::eval;
use evaluatorrs::formulas::ParserError;

fn evaluate() -> Result<(), ParserError> {
    let expression = "1 + 2";
    let result = eval(expression)?;
    debug_assert_eq!(result, 3.0);
    Ok(())
}

Example 2

use evaluatorrs::formulas::{Evaluate, RootFormula};
use evaluatorrs::function_stores::EmptyFunctionStore;
use evaluatorrs::variable_stores::{HashMapVariableStore, SetVariable};

fn example() -> Result<(), ParserError> {
    let formula = RootFormula::parse("a + b", &EmptyFunctionStore)?;
    let mut variable_store = HashMapVariableStore::new();
    variable_store.set("a", RootFormula::parse("1", &EmptyFunctionStore)?);
    variable_store.set("b", RootFormula::parse("10", &EmptyFunctionStore)?);
    let evaluated = formula.eval(&variable_store);
    assert!(evaluated.is_ok());
    let evaluated = evaluated?;
    assert_eq!(evaluated, 11.0);
 }

Dependencies

~98KB