Expression Evaluator

A simple and flexible Dart library to evaluate dynamic expressions with support for logical operators (AND, OR) and comparison operations (==, !=, <, >, ILIKE, LIKE). This package is designed to make it easy to evaluate expressions based on variable values, and can be used for a variety of logical and mathematical evaluations.

Features

Supports logical operators AND (&&) and OR (||).
Handles comparison operators: equality (==), inequality (!=), less than (<), greater than (>), and pattern matching (LIKE, ILIKE).
Flexible expression evaluation with dynamic variables.
Simple API for integration into your Dart projects.

Installation

To use this package in your Dart project, add the following dependency in your pubspec.yaml file:

dependencies:
  expression_evaluator: ^1.0.7

Then run:

dart pub get

Usage

import 'package:expression_evaluator/expression_evaluator.dart';

void main() {
  var variables = {
    'x': '10',
    'y': '20',
    'z': 'hello',
  };

  var evaluator = ExpressionEvaluator(variables);

  var expression1 = 'x > 5 AND y < 25'; // Should return true
  var expression2 = 'z == "world" OR x == "10"'; // Should return true
  var expression3 = 'x == 15 AND z != "hello"'; // Should return false

  print('Expression 1: $expression1 => ${evaluator.evaluate(expression1)}');
  print('Expression 2: $expression2 => ${evaluator.evaluate(expression2)}');
  print('Expression 3: $expression3 => ${evaluator.evaluate(expression3)}');
}

Available Operators

Equality (==): Checks if two values are equal.
Inequality (!=): Checks if two values are not equal.
Less Than (<): Checks if the left value is less than the right value.
Greater Than (>): Checks if the left value is greater than the right value.
LIKE: Pattern matching with wildcard support (% for multiple characters, _ for a single character).
ILIKE: Case-insensitive pattern matching, similar to LIKE.
AND: Logical operator that returns true if both conditions are true.
OR: Logical operator that returns true if at least one condition is true.

Example

You can find an example script in the example/ folder that demonstrates how to use the ExpressionEvaluator in a real-world scenario.

dart example/expression_evaluator_example.dart

API