Crate xxcalc

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

StringProcessor

Transforms text expression into list of tokens.

TokensProcessor

Transforms list of tokens into another list of tokens.

TokensReducer

Evaluates list of tokens into a single Polynomial value.

Type Aliases

Identifiers

Vector of unique identifiers.

TokenList

List of tokens with their position.