antlr-calculator
This calculator is using the ANTLR4 TypeScript target to calculate results from formulas that are passed in as string. Both JavaScript and TypeScript are supported.
Whenever a calculation is performed, a CalculationResult is returned with the following properties:
| Property | Type | |
|---|---|---|
| isValid | boolean | true if the formula could be parsed and calculated, else false |
| errorPosition | number | Position of the offending symbol in the line, 0 based index, for invalid results, else null |
| errorMessage | string | ANTLR error message for invalid formulas, else null |
| result | number | NaN for invalid formulas, else the actual result |
You can check out the live demo here!
You can find the .NET version here: https://github.com/GeorgDangl/Dangl.Calculator
Installation
Clone this repository or just go with npm install antlr-calculator.
JavaScript
Just reference dist/bundle.js and the global variable antlrCalc is available.
var result = antlrCalc.Calculator.calculate('4*5');
console.log(JSON.stringify(result, null, 2));
// {
// "isValid": true,
// "errorPosition": null,
// "errorMessage": null,
// "result": 20
// }TypeScript
Import the Calculator class and use the static calculate(formula: string) method to evaluate formulas.
import { Calculator } from 'antlr-calculator';
var result = Calculator.calculate('4*5');
console.log(JSON.stringify(result, null, 2));
// {
// "isValid": true,
// "errorPosition": null,
// "errorMessage": null,
// "result": 20
// }Supported functions
| Expression | |
|---|---|
FLOOR expression |
Round down to zero accuracy |
CEIL expression |
Round up to zero accuracy |
ABS expression |
Absolute value |
ROUNDK '(' expression ';' expression ')' |
Round expr_1 with expr_2 accuracy |
ROUND expression |
Round with zero accuracy |
TRUNC expression |
Trim decimal digits |
SIN expression |
Sinus |
COS expression |
Cosinus |
TAN expression |
Tangens |
COT expression |
Cotangens |
SINH expression |
Sinus Hypererbolicus |
COSH expression |
Cosinus Hyperbolicus |
TANH expression |
Tangens Hyperbolicus |
ARCSIN expression |
Inverse Sinus |
ARCCOS expression |
Inverse Cosinus |
ARCTAN expression |
Inverse Tangens |
ARCTAN2 '(' expression ';' expression ')' |
Atan2 |
ARCCOT expression |
Inverse Cotangens |
EXP expression |
e ^ expr |
LN expression |
Logarithm to e |
EEX expression |
10 ^ expr |
LOG expression |
Logarithm to 10 |
RAD expression |
Angle to radians (360° base) |
DEG expression |
Radians to angle (360° base) |
SQRT expression |
Square root |
SQR expression |
Square product |
expression op = ('^' | '\*\*') expression |
expr_1 to the expr_2 th power |
expression (MOD | '%' ) expression |
Modulo |
expression DIV expression |
Whole part of division rest |
expression op = ('~' | '//') expression |
expr_1 nth root of expr_2 |
expression op = ('\*' | '/') expression |
Multiplication or division |
expression op = ('+' | '-') expression |
Addition or subtraction |
NUMBER |
Single integer or float number |
'(' expression ')' |
Expression within parentheses |
MIN '(' expression (';' expression)* ')' |
Minimum |
MAX '(' expression (';' expression)* ')' |
Maximum |
PI '()'? |
Mathematical constant pi = 3,141593 |
expression E+ expression |
Exponent, e.g. 10e+43 |
expression E- expression |
Inverted Exponent, e.g. 10e-43 |
EULER |
Mathematical constant e = 2,718282 |
'-' expression |
Unary minus sign (negative numbers) |
'+' expression |
Unary plus sign (positive numbers) |
'(' expression ')' expression |
Expressions without multiplication sign, e.g. 2(3) -> 2*(3) |
expression '(' expression ')' |
Expressions without multiplication sign, e.g. 2(3) -> 2*(3) |
expression may be any expression as functions can be nested. Example: DEG(2*PI) or LOG(10^3).
Formulas can be case invariant, e.g. SIN, sin and siN are all considered the same.
Comments in Formulas
Comments in Formulas are supported by encapsulating them either in /*...*/, '...' or "..." quote styles. Examples:
4/*Length*/*3/*Width*/ resolves to 12
4'Length'*3'Width' resolves to 12
4"Length"*3"Width" resolves to 12
Substitutions
The calculator can be called with an overload that accepts a callback function for substitution values. For example, take the following formula:
1,2*#Z4+3
Here, #Z4 is a substitution, which is a placeholder that can be externally supplied. Let's say you want to resolve #Z4 to the value three, you could make this simple call:
const formula = '1,2*#Z4+3';
const result = Calculator.calculate(formula, (substitution) => {
if (substitution === '#Z4') {
return 3;
}
return null;
});The callback is in the form of a (substitution: string) => number, and it will be called for every substitution found in the formula. Multiple substitutions are supported. If duplicates in substitutions are present, the calculator will request each one individually. If a substitution resolves to null, the formula is considered invalid.
Substitutions must always start with the # character and can then have the following characters: [a-z] | [A-Z] | [äÄöÖüÜ] | [0-9]
Trailing comments
Formulas may be terminated with a semicolon ; at the end, followed by extra input that is not evaluated. This is useful when, instead of regular comments, you
just want to attach some trailing formation at the end of a formula. For example, the following formula:
1 + 3; As per our counting
Would just evaluate the 1 + 3 portion and return a valid result with the value 4, ignoring the trailing semicolon and all input that follows.