Yhtiyar/ExpressionParser

Java math expression builder and parser

ExpressionParser

Java math expression parser

Readme is outdated(it is still relevant, but I've made some updates that simlifies usage), will be updated soon.

Usage

                
ExpressionParser ep = new DoubleExpressionParser(); //All evaluation will be for Double type

/*For parsing and evaluating as BigInteger type*/
ExpressionParser bigIntegerParser = new BigIntegerExpressionParser();

try {
    System.out.println(ep.parse("x*y + log2 (5*x) + z - 2*x").evaluate(5d, 1.5d, 2.9d));
    System.out.println(ep.parse(pow2(x) min (1 + z^10 / y));
    System.out.println(new CheckedAdd<>(new Const<>(3), new Const<>(5), new IntegerOperation()).evaluate(0, 0, 0);
    
}
catch (ParserException e){
    System.out.println(e);
}

evalute(x, y, z) takes 3 arguments - values of x, y and z.

I will update it later to take not fixed amount of variables but, map of variables-values

Exceptions

All operations are checked while evaluations, so you will get EvaluateException if there will be problem while evaluation, e.g. overflow, division by zero

Parser exeptions You will get ParserException if you will try to parse invalid exception

Note: to see all exceptions open expression/exception folder

Operations

1. +
2. -
3. *
4. /
5. pow2 2^expr Usage: pow2(expr), could be used without brackets if there is only one argument: pow2 x
6. log2 log2(expr)
7. count count of active bits in binary form of number count 8 = 1; count(4 + 3) = 3
8. min usage 1 min 2 -> 1, NOTE: it has lowest priority while evaluating, so 1+2*3 min 3*1+1 -> 4
9. max usage same as min 10 ^ power, usage 2^10 -> 1024

Each operation has its own class.

Generics

Each expression will be parsed and evaluated on the type you will provide in constructor of expressionParser. For the Const, you need to provide Type : c = new Const<Integer>(3); c = new Const<Double>(3.d) For the operations, it is required to provide Operation type in constructors new CheckedAdd<>(new Const<>(3), new Const<>(5), new IntegerOperation())

Types

1. Integer usage new Const<Integer>(3);
2. Double
3. BigInteger

Operation types

1. IntegerOperation
2. DoubleOperation
3. BigIntegerOperation