Crate xxcalc

Source
Expand description

xxcalc is a crate which provides an embeddable floating-point polynomial calculator and linear solver.

You can use xxcalc to embed mathematical expression evaluator in your own programs. By default the calculator provides addition +, subtraction -, multiplication *, division / and exponentation ^ operators. Some functions such as log and log10 are implemented, as well as pi and e constants. This is a polynomial calculator, so you can perform arithmetic operations on polynomials (using x symbol by default) - a simple floating-point number is just a special case of a polynomial (the constant polynomial, polynomial of degree zero).

Furthermore the crate is well structurized and documented - you can use pieces it provides to create your own custom solutions (you can use or change a tokenizer, parser and evaluator however you want). Look at implementations of PolynomialParser, LinearSolverParser, PolynomialEvaluator or LinearSolverEvaluator to see how to extend default implementations.

With the crate a xxcalc binary is provided which can be used as a standalone CLI calculator (which can be replacement for bc command). If the crate is installed with a feature “interactive” enabled, a history of commands is enabled.

Whole library is meticulously tested, use cargo test to run unit tests (including doc examples), cargo bench will run simple benchmarks, while cargo bench -- --ignored will run more computation-heavy benchmarks.

§Examples

You can easily take a LinearSolver or PolynomialCalculator to embed mathematical engine inside your programs.

use xxcalc::linear_solver::LinearSolver;
use xxcalc::calculator::Calculator;
use xxcalc::polynomial::Polynomial;

assert_eq!(LinearSolver.process("2x + 1 = 2(1-x)"), Ok(Polynomial::constant(0.25)));
assert_eq!(LinearSolver.process("0.1*-2+4"), Ok(Polynomial::constant(3.8)));

Please see documentation for PolynomialCalculator for more examples.

Modules§

  • calculator
    Calculator is an easy to use generic method of evaluating string expressions.
  • evaluator
    Evaluator is a TokensReducer, it takes token in RPN form and evaluates its Polynomial value.
  • linear_solver
    Defines a LinearSolver which extends a PolynomialCalculator with ability of solving single linear equation.
  • parser
    Parser is a TokensProcessor, it takes Tokens in a classical infix form and transforms them into Reverse Polish Notation form for further evaluation.
  • polynomial
    Defines Polynomial expression with basic operators on it.
  • polynomial_calculator
    Defines a PolynomialCalculator with common arithmetic operations, functions and constants already defined.
  • tokenizer
    Tokenizer is a StringProcessor, it takes string expression and converts it into Tokens for further processing.

Structs§

  • Tokens
    Tokens is a compound storage for list of tokens with their identifiers.

Enums§

  • EvaluationError
    An error that occurs during token reduction, usually by an evaluator.
  • ParsingError
    An error that occurs during token processing, usually by a parser.
  • Token
    Token is a basic unit returned after tokenization using a StringProcessor.

Traits§

Type Aliases§