goJACEgo

goJACEgo is a high performance calculation engine for Go, written in pure Go.

'Jace' stands for "Just Another Calculation Engine". it is a port of Jace.NET

What does it do?

goJACEgo can interprete and execute strings containing mathematical formulas. These formulas can rely on variables. If variables are used, values can be provided for these variables at execution time of the mathematical formula.

Architecture

goJACEgo follows a design similar to most of the modern compilers. Interpretation and execution is done in a number of phases:

Tokenizing

During the tokenizing phase, the string is converted into the different kind of tokens: variables, operators and constants.

Abstract Syntax Tree Creation

During the abstract syntax tree creation phase, the tokenized input is converted into a hierarchical tree representing the mathematically formula. This tree unambiguously stores the mathematical calculations that must be executed.

Optimization

During the optimization phase, the abstract syntax tree is optimized for executing.

More Information: https://pieterderycke.wordpress.com/2012/11/04/jace-net-just-another-calculation-engine-for-net/

Getting Started

goJACEgo can be used in a couple of ways:

To directly execute a given mathematical formula using the provided variables:

engine, _ := gojacego.NewCalculationEngine()

vars := map[string]interface{}{
   "a":2,
   "b":5
}

result, _ := engine.Calculate("a*b", vars)
// 10.0

To build a Func accepting a map as input containing the values for each variable:

engine, _ := gojacego.NewCalculationEngine(gojacego.WithDecimalSeparator('.'),
		                                     gojacego.WithArgumentSeparator(','),
		                                     gojacego.WithCaseSensitive(false),
		                                     gojacego.WithOptimizeEnabled(true),
		                                     gojacego.WithDefaultConstants(true),
		                                     gojacego.WithDefaultFunctions(true))

formula := engine.Build("a*b")

vars := map[string]interface{}{
   "a":2,
   "b":5
}

result, := formula(vars)
// 10.0

Features

Basic Operations

The following mathematical operations are supported:

• Addition: +
• Subtraction: -
• Multiplication: *
• Division: /
• Modulo: %
• Exponentiation: ^

Boolean Operations

The following boolean operations are supported:

• Less than: <
• Less than or equal: <=
• More than: >
• More than or equal: >=
• Equal: ==
• Not Equal: !=

The boolean operations map true to 1.0 and false to 0.0. All functions accepting a condition will consider 0.0 as false and any other value as true.

result, _ := engine.Calculate("5 > 1", nil)
// 1.0

Scientific Notation

result, _ := engine.Calculate("1E-3*5+2", nil)
// 2.005

Variables

vars := map[string]interface{}{
	"$a":  1,
	"B":   2,
	"c_c": 3,
	"d1":  4,
	"VaR_vAr": 10
}

result, _ := engine.Calculate("$a + B + c_c + d1 + 10 + VaR_vAr", vars)
// 30.0

• Can contains letters ( a-z | A-Z ), underscore ( _ ), dolar sign ( $ ) or a number ( 0-9 ).
• Cannot start with a number.
• Cannot start with underscore.

Standard Constants

Constant	Description	More Information
e	Euler's number	https://oeis.org/A001113
pi	Pi	https://oeis.org/A000796

result, _ := engine.Calculate("2*pi", nil)
// 6.283185307179586

Standard Functions

The following mathematical functions are out of the box supported:

Function	Arguments	Description	More Information
sin	sin(x)	Sine	https://pkg.go.dev/math#Sin
cos	cos(x)	Cosine	https://pkg.go.dev/math#Cos
asin	asin(x)	Arcsine	https://pkg.go.dev/math#Asin
acos	acos(x)	Arccosine	https://pkg.go.dev/math#Acos
tan	tan(x)	Tangent	https://pkg.go.dev/math#Tan
atan	atan(x)	Arctangent	https://pkg.go.dev/math#Atan
log	log(x)	Logarithm	https://pkg.go.dev/math#Log
sqrt	sqrt(x)	Square Root	https://pkg.go.dev/math#Sqrt
trunc	trunc(x)	Truncate	https://pkg.go.dev/math#Trunc
floor	floor(x)	Floor	https://pkg.go.dev/math#Floor
ceil	ceil(x)	Ceil	https://pkg.go.dev/math#Ceil
round	round(x [,y])	Round	Rounds a number to a specified number of digits where 'x' is the number and 'y' is the digits.
random	random(x)	Random	Generate a random double value between 0.0 and 1.0 where 'x' is the seed.
if	if(a,b,c)	Excel's IF Function	IF 'a' IS true THEN 'b' ELSE 'c'.
max	max(x1,…,xn)	Maximum	Return the maximum number of a series.
min	min(x1,…,xn)	Minimum	Return the minimum number of a series.

// Sin (ordinary function)
vars := map[string]interface{}{
   "a":2,
}
ret, _ := engine.Calculate("sin(100)+a", vars)
// 1.4936343588902412

// Round
retRound, _ := engine.Calculate("round(1.234567,2)", nil)
// 1.23

// If
vars := map[string]interface{}{
   "a":4,
}

ifresult, _ := engine.Calculate("if(2+2==a, 10, 5)", varsIf)
// 10.0

// MAX
max, _ := engine.Calculate("max(5,6,3,-4,5,3,7,8,13,100)", nil)
// 100.0

Custom Functions

Custom functions allow programmers to add additional functions besides the ones already supported (sin, cos, asin, …). Functions are required to have a unique name. The existing functions cannot be overwritten.

engine.AddFunction("addTwo", func(arguments ...interface{}) float64{
		return arguments[0] + 2
}, true)

result, _ := engine.Calculate("addTwo(2.0)", nil)
// 4.0

Compile Time Constants

Variables as defined in a formula can be replaced by a constant value at compile time. This feature is useful in case that a number of the parameters don't frequently change and that the formula needs to be executed many times. Thusfore it is better because constants could be optimizated on 'Optimization phase'.

consts := map[string]interface{}{
   "a":1,
}
formula := engine.BuildWithConstants("a+b+c", consts)
// It's the same as 'engine.Build("1+b+c")' but without dealing with string replace

vars := map[string]interface{}{
   "b":2,
   "c":5
}

result, := formula(vars)
// 8.0

Benchmark

https://github.com/mrxrsd/golang-expression-evaluation-comparison

goJACEgo vs Others

Test
Benchmark_bexpr-8	2278 ns/op
Benchmark_celgo-8	127.0 ns/op
Benchmark_evalfilter-8	1646 ns/op
Benchmark_expr-8	119.1 ns/op
Benchmark_goja-8	306.9 ns/op
Benchmark_gojacego-8	117.3 ns/op
Benchmark_govaluate-8	259.9 ns/op
Benchmark_gval-8	295.0 ns/op
Benchmark_otto-8	951.2 ns/op
Benchmark_starlark-8	5971 ns/op

goJACEgo vs Govaluate vs Expr vs Gval

Test	Gojacego	Govaluate	Expr	Gval
BenchmarkEvaluationNumericLiteral	5.42 ns/op	71.73 ns/op	87.71 ns/op	1.89 ns/op
BenchmarkEvaluationLiteralModifiers	5.63 ns/op	180.8 ns/op	69.92 ns/op	1.85 ns/op
BenchmarkEvaluationParameter	11.25 ns/op	72.47 ns/op	69.75 ns/op	147.1 ns/op
BenchmarkEvaluationParameters	31.91 ns/op	122.0 ns/op	202.2 ns/op	315.6 ns/op
BenchmarkEvaluationParametersModifiers	56.32 ns/op	233.3 ns/op	368.6 ns/op	378.5 ns/op
BenchmarkComplexPrecedenceMath	4.73 ns/op	18.20 ns/op	67.96 ns/op	1.93 ns/op
BenchmarkMath	39.22 ns/op	243.7 ns/op	252.1 ns/op	395.3 ns/op

Disclaimer: GoJACEgo has only mathematical and logical operators while others has more features.