The Go Expression Toolkit (Go-ExprTk) is a wrapper library based on C++ Mathematical Expression Toolkit Library (ExprTk).

It is a simple to use, easy to integrate and extremely efficient run-time mathematical expression parser and evaluation engine.

Go-ExprTk supports numerous forms of functional, logical and vector processing semantics and is very easily extendible.

go get github.com/Pramod-Devireddy/go-exprtk

package main

import (
	"fmt"

	"github.com/Pramod-Devireddy/go-exprtk"
)

func main() {
	exprtkObj := exprtk.NewExprtk()
	defer exprtkObj.Delete()

	exprtkObj.SetExpression("(x + 2)*(y-2)")

	exprtkObj.AddDoubleVariable("x")
	exprtkObj.AddDoubleVariable("y")

	err := exprtkObj.CompileExpression()
	if err != nil {
		fmt.Println(err.Error())
		return
	}

	exprtkObj.SetDoubleVariableValue("x", 18)
	exprtkObj.SetDoubleVariableValue("y", 32)

	fmt.Println(exprtkObj.GetEvaluatedValue())
}

Check out more Examples

The Go-ExprTk library has the following capabilities:

• Mathematical operators (+, -, *, /, %, ^)

• Functions (min, max, avg, sum, abs, ceil, floor, round, roundn, exp, log, log10, logn, pow, root, sqrt, clamp, inrange, swap)

• Trigonometry (sin, cos, tan, acos, asin, atan, atan2, cosh, cot, csc, sec, sinh, tanh, d2r, r2d, d2g, g2d, hyp)

• Equalities & Inequalities (=, ==, <>, !=, <, <=, >, >=)

• Assignment (:=, +=, -=, *=, /=, %=)

• Logical operators (and, nand, nor, not, or, xor, xnor, mand, mor)

• Control structures (if-then-else, ternary conditional, switch case, return-statement)

• Loop structures (while loop, for loop, repeat until loop, break, continue)

• Optimization of expressions (constant folding, strength reduction, operator coupling, special functions and dead code elimination)

• String operations (equalities, inequalities, logical operators, concatenation and sub-ranges)

• Expression local variables, vectors and strings

• User defined variables, vectors, strings, constants and function support

• Multivariate function composition

• Multiple sequence point and sub expression support

• Numeric integration and differentiation

• Vector Processing: BLAS-L1 (axpy, axpby, axpb), all/any-true/false, count, rotate-left/right, shift-left/right, sort, nth_element, iota, sum, kahan-sum, dot-product, copy

This module could not be possible without the ExprTk library by Arash Partow and the idea of creating the wrapper module by Narayana Rao G S

Published under MIT License