Handle assignment expressions

[kmahmood74]

I was trying a simple expression as follows but it keeps throwing errors -
`
void example_2() {
// Parse expression:
var expression = Expression.parse("person.name='John'");
var context = {'person': Person('Jane')};
final evaluator = const MyEvaluator();
var r = evaluator.eval(expression, context);
}

class Person {
String name;
Person(this.name);
Map<String, dynamic> toJson() => {'name': name};
}

class MyEvaluator extends ExpressionEvaluator {
const MyEvaluator();
@OverRide
dynamic evalMemberExpression(
MemberExpression expression, Map<String, dynamic> context) {
var object = eval(expression.object, context).toJson();
return object[expression.property.name];
}
}
The exception I get is as follows - Unhandled exception:
end of input expected at 1:12
#0 Failure.value (package:petitparser/src/context/failure.dart:13:18)
#1 Expression.parse (package:expressions/src/expressions.dart:32:55)
#2 example_2 (file:///Users/khurrammahmood/StudioProjects/expressions/example/expressions_example.dart:29:31)
#3 main (file:///Users/khurrammahmood/StudioProjects/expressions/example/expressions_example.dart:6:3)
#4 _delayEntrypointInvocation. (dart:isolate-patch/isolate_patch.dart:283:19)
#5 _RawReceivePortImpl._handleMessage (dart:isolate-patch/isolate_patch.dart:184:12)

`

[rbellens]

Assignments are not supported.