formula_parser

Description:

formula parser

Formula Parser for Dart #
A dart plugin to to parse and evaluate mathematical expressions.





Formula Parser is a Dart library that allows you to parse and evaluate mathematical expressions.
The grammar for this library is built using petitparser library.
This library is open source, stable and well tested. Development happens on GitHub. Feel free to report issues or create a pull-request there.
The package is hosted on dart packages. Up-to-date API documentation is created with every release.
Installation #
To use Formula Parser in your Dart project, add the following dependency to your pubspec.yaml file:
dependencies:
formula_parser: ^latest
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Then, run flutter packages get
or to install it on another dart project, run the below command
dart pub add formula_parser
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Usage #
Import the package in your Dart file:
import 'package:formulaparser/formulaparser.dart';
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Create a FormulaParser instance with the expression and variables:
var exp = FormulaParser('a+b+150', {'a': 10, 'b': 20 });
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To parse the expression,
var result = exp.parse;
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Check if the parsing was successful:
if (result.isSuccess) {
print('Result: \${result.value}');
} else {
print(result.isFailure);
print(result.position);
print(result.message);
}
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Features #

Parses and evaluates mathematical expressions.
Supports variables and functions in the expressions.
Handles error cases and provides error messages.

Supported Math Functions #
The following math functions are supported by the Formula Parser:



Function
Description
Example




ADD
Addition
ADD(2, 3)


SUB
Subtraction
SUB(5, 2)


MUL
Multiplication
MUL(4, 5)


DIVI
Division
DIVI(10, 2)


AVG
Average
AVG(2, 3, 4, 5)


POWER
Exponentiation
POWER(2, 3)


SQRT
Square Root
SQRT(4)


CEIL
Ceiling
CEIL(4.2)


FLOOR
Floor
FLOOR(4.8)


ROUND
Round
ROUND(4.5)


ABS
Absolute
ABS(-4.5)


EXP
Exponential
EXP(2)


LOG
Natural Logarithm
LOG(10)


SIN
Sine
SIN(0)


ASIN
Arcsine
ASIN(0)


COS
Cosine
COS(0)


ACOS
Arccosine
ACOS(0)


TAN
Tangent
TAN(0)


ATAN
Arctangent
ATAN(0)



To use these functions, you can include them in your expressions. For example:
var exp = FormulaParser('1+ADD(4,4)+MUL(2,DIVI(2,3))+AVG(2,3,4,5)/5+POWER(2,2)+SQRT(4)+CEIL(4.2)+FLOOR(4.8)+ROUND(4.5)+ABS(-4.5)+EXP(2)+LOG(10)+SIN(0)+ASIN(0)+COS(0)+ACOS(0)+TAN(0)+ATAN(0)');
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The following comparison functions are supported by the Formula Parser:



Function
Description
Example




EQ
Equal
EQ(2,2)


NE
Not Equal
NE(2,3)


LT
Less Than
LT(2,3)


GT
Greater Than
GT(2,3)


GTE
Less Than or Equal To
LTE(2,3)


LTE
Greater Than or Equal To
GTE(2,3)



Supported Operators #
The following operators are supported by the Formula Parser:



Operator
Description
Example




+
Addition
2 + 3


-
Subtraction
5 - 2


*
Multiplication
4 * 5


/
Division
10 / 2


^
Exponentiation
2 ^ 3


Comparison Operators




==
Equal
2 == 2


!=
Not Equal
5 != 2


<
Less Than
4 < 5


>
Greater Than
10 > 2


<=
Less Than or Equal To
2 <= 3


>=
Greater Than or Equal To
5 >= 2



Documentation #
The FormulaParser class provides the following methods and properties:
FormulaParser(expression: String, [options: Map<String, dynamic>]) #
Constructs a FormulaParser instance with the given expression and options.

expression: The mathematical expression to parse.
options (optional): A map of variables to their values.

error #
Indicates whether an error occurred during parsing.

Returns true if an error occurred, false otherwise.

errorMessage #
The error message describing the error that occurred during parsing.

Returns the error message as a String.

parsedExpression #
The parsed expression after preprocessing.

Returns the parsed expression as a String.

parse #
Parses the expression and returns the result.

Returns the parsed result.

Contributing #
Contributions are welcome! If you find any issues or have suggestions for improvements, please open an issue or submit a pull request on the GitHub repository.
License #
This project is licensed under the MIT License. See the LICENSE file for details.