ecp_expression_language 1.0.0

Library for parsing and evaluating simple expression language with additional references

example/main.dart

import 'package:ecp_expression_language/ecp_expression_language.dart';

void main() {
  var text = "title == 1&&title!=2";
  var leftReg = RegExp(r'([\w\s])+(?=(==|!=))', caseSensitive: false);
  var rightReg = RegExp(r'(?<=(==|!=)).*?((?=(&{2}|\|{2}|\)))|$)',
      caseSensitive: false, unicode: true);
  text = text.replaceAllMapped(
      leftReg, (match) => "\"${match.group(0)?.trim()}\"");
  text = text.replaceAllMapped(rightReg, (match) {
    return "\"${match.group(0)?.trim()}\"";
  });
  print(text);
  var expressionGrammarDefinition = ExpressionGrammarParser({
    // "element": TestElement(),
  });
  var parser = expressionGrammarDefinition.build();
  var result = parser.parse(text);
  var expression = result.value as Expression<bool>;
  var value = expression.evaluate();
  print(value);
}

// class TestElement extends ExpressionProviderElement {
//   Map<String, ExpressionProvider> properties = {
//     'value': ConstantExpressionProvider<String>("27"),
//   };
//
//   @override
//   String? id;
//
//   @override
//   ExpressionProvider getExpressionProvider([String? propertyName]) {
//     if (propertyName == null || propertyName == '') {
//       propertyName = 'value';
//     }
//     return properties[propertyName]!;
//   }
//
//   @override
//   ExpressionProviderElement clone(
//       ExpressionProvider<ExpressionProviderElement> parent) {
//     return this;
//   }
// }
//
// class ConstantExpressionProvider<T> extends ExpressionProvider<T> {
//   final T value;
//
//   ConstantExpressionProvider(this.value);
//
//   @override
//   Expression<T> getExpression() {
//     return ConstantExpression(value);
//   }
// }