AterCalculator

A JavaScript Calculator that uses the Reverse Polish Notation and the Shunting-yard Algorithm to solve problems.

How to use it

Solving a human-readable problem

var c = new AterCalculator();
c.solve('5^3+(-(6-8)*sqrt(4^3))-3/6');//140.5

Parse unary minus

c.parseUnaryMinus('-1-2(-3-4)-5+-6---7');//#1-2(#3-4)-5+#6-##7

Note: This method strips white spaces.

Get an array of Shunting-yard tokens from a human-readable problem

c.shuntingYard('5^3+(#(6-8)*sqrt(4^3))-3/6');//[5, 3, "^", 6, 8, "-", "#", 4, 3, "^", "sqrt", "*", "+", 3, 6, "/", "-"]

Note: You have to use the # to represent the unary minus. If you don't and try to use the output in the solveReversePolishNotation method it will throw an exception.

Solving a Reverse Polish Notation array

c.solveReversePolishNotation([5, 3, "^", 6, 8, "-", "#", 4, 3, "^", "sqrt", "*", "+", 3, 6, "/", "-"]);//140.5

Customising the Calculator

Adding a new operator

c.operators['~'] = {
    operands: 1,
    associativity: 'r',
    precedence: 10,
    func: function(a) {
        return ~a;
    }
};
c.solve('~4');//-5

Structure of operators

Attribute	Explanation	Values
operands	Number of arguments that func needs. This correspond to the number of operands to operate.	1 or 2
associativity	Associativity of the operator.	'l' or 'r' for left or right respectively
precedence	Precedence of the operator. A greater number indicates a greater priority.	An integer
func	The function definition of the operator.	A function with a number of parameters equal to operands attribute

Adding a new function

c.functions['myFunc'] = {
    operands: 2,
    func: function(a, b) {
        return a*2-b;
    }
};
c.solve('myFunc(5, 3)');//7

Structure of functions

Attribute	Explanation	Values
operands	Number of arguments that func needs.	An integer from 0 to ...
func	The function definition.	A function with a number of parameters equal to operands attribute

Adding a new symbol

c.symbols['SQRT2'] = Math.SQRT2;
c.solve('SQRT2');//1.4142135623730951

Calculator internal attributes

• decimals: Number of decimals returned by built-in functions
• unaryMinus: Unary minus operator symbol
• binaryMinus: Binary minus (Sustraction) operator symbol

Note: Changing unaryMinus or binaryMinus changes the behaviour of parseUnaryMinus only (And because of that, the behaviour of the solve method).

Prefer using the setUnaryMinusSymbol and setBinaryMinusSymbol methods instead.

c.setUnaryMinusSymbol('%');
c.solve('#1');//1
c.solve('%1');//-1

Catching errors

try {
   console.log(c.solveReversePolishNotation(c.shuntingYard('5^3+(-(6-8)*sqrt(4^3))-3/6')));
} catch(e) {
   console.log(e);//"Insufficient values in the expression."
}

This error is thrown because the "-" operator is binary and expects 2 operands in -(6-8). Use # instead #(6-8).

Built-in Stuff

Operators

Operation	Symbol	Operands	Precedence	Associativity
Addition	+	2	1	Left
Sustraction	-	2	1	Left
Multiplication	*	2	2	Left
Division	/	2	2	Left
Exponentiation	^	2	3	Right
Unary Minus	- (Context-dependent) # (Explicit unary minus)	1	10	Right

Functions

Function	Notation	Operands
Sine	sin	1
Cosine	cos	1
Tangent	tan	1
Arcsine	asin	1
Arccosine	acos	1
Arctangent	atan	1
Square root	sqrt	1
nth root	nrt	2 (degree of the root, x)

Note: The built-in trigonometric functions expect and return angles in degrees.

Symbols

Symbol	Value
pi	Math.PI
e	Math.E
π	Math.PI

License

Copyright (c) 2016 Gustavo Alfredo Marín Sáez

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.