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[SOLVED] Serializer Enum [message #1411842]

Sun, 24 August 2014 11:57

Eclipse User

Hi!

I've got a problem regarding the usage of enums.

Here's a part of my used grammar:

// boolAndExpr -> boolOrExpr (andoperation boolOrExpr)*
boolAndExpr returns BooleanExpression:
	boolOrExpr ({BooleanOperatorExpression.left=current} operation=andoperation right=boolOrExpr)*
;
	
// andoperation -> AND
enum andoperation returns BooleanOperations:
	AND
;

// boolOrExpr -> compareExpr (oroperations compareExpr)*
boolOrExpr returns BooleanExpression:
	compareExpr ({BooleanOperatorExpression.left=current} operation=oroperations right=compareExpr)*
;

// oroperations -> OR|XOR
enum oroperations returns BooleanOperations:
	OR | XOR
;

Parsing works pretty good, but when it comes to serializing something containing an AND this Exception comes up:

The value 'AND' is invalid for enum oroperations
Valid values are: OR, XOR
Semantic Object: BooleanOperatorExpression

I think it could be easily changed by changing the model and split up AND- and OR-Operations into two classes. But as it is a running system to which I only add the Xtext-things, I do not want to change the model that much... So any idea how to solve this?

Thanks in advance for any hints!
Jonas

[Updated on: Sun, 24 August 2014 14:18] by Moderator

Re: Serializer Enum [message #1411854 is a reply to message #1411842]

Sun, 24 August 2014 12:50

Eclipse User

i thinks the problem is how you missuse the enum

its actual declaration should be

enum BooleanOperations:
AND | OR | XOR
;

Re: Serializer Enum [message #1411859 is a reply to message #1411854]

Sun, 24 August 2014 13:08

Eclipse User

Hi!

Thanks for the quick response!

I actually know how to do that, but as you may have noticed the Enum is split into two parts ([X]OR and AND) and AND should be only available in the boolAndExpr-rule while the others should be only available in the boolOrExpr-rule. This is to preserve precedence to be able to express things like "x OR y AND z OR p AND f" without using paranthesis or something...

Best regards
Jonas

Re: Serializer Enum [message #1411870 is a reply to message #1411859]

Sun, 24 August 2014 13:46

Eclipse User

the question is what happens if you write a third rule that is never called but has all options

Re: Serializer Enum [message #1411877 is a reply to message #1411870]

Sun, 24 August 2014 14:18

Eclipse User

Hi!

Thanks a lot!

This works great:

...

//BooleanExpression -> boolOrExpr (BooleanOperations boolOrExpr)*
// Note: This is a workaround for the serializer to work with AND-Operations!
BooleanExpression:
	boolOrExpr ({BooleanOperatorExpression.left=current} operation=BooleanOperations right=boolOrExpr)*
;

//BooleanOperations -> AND | OR | XOR
enum BooleanOperations:
	AND | OR | XOR
;

// boolAndExpr -> boolOrExpr (andoperation boolOrExpr)*
boolAndExpr returns BooleanExpression:
	boolOrExpr ({BooleanOperatorExpression.left=current} operation=andoperation right=boolOrExpr)*
;
	
// andoperation -> AND
enum andoperation returns BooleanOperations:
	AND
;

// boolOrExpr -> compareExpr (oroperations compareExpr)*
boolOrExpr returns BooleanExpression:
	compareExpr ({BooleanOperatorExpression.left=current} operation=oroperations right=compareExpr)*
;

// oroperations -> OR|XOR
enum oroperations returns BooleanOperations:
	OR | XOR
;

...

Best regards
Jonas

[Updated on: Sun, 24 August 2014 14:19] by Moderator

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