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Unassigned Rule Calls - 'current' already created [message #1822587]

Tue, 10 March 2020 09:50

Rob K

Messages: 5
Registered: January 2020

Junior Member

Hi,

PROBLEM:
The following code snippet has the following error at 'TypeReference' and 'VectorTypeConstructor' in Type: 'An unassigned rule call is not allowed, when the 'current' was already created.'

Type:
	isImmutable?='immutable' (TypeReference | VectorTypeConstructor) (range = Range)?
;

VectorTypeConstructor:
	type = [TypeDecl] (dimensions += Dimension)+
;

TypeReference:
	type = [TypeDecl]
;

This is caused when I added 'isImmutable?='immutable'' to the start of Type.

WHY THIS IS A PROBLEM:
I can add an assignment : 'type = (TypeReference | VectorTypeConstructor)' but that breaks a lot of existing code (i'm editing a big project). Getting the TypeDecl object from Type would change from 'Type.type' to 'Type.type.type'

SOLUTIONS TRIED:
Removing the 'isImmutable?='immutable'' part removes the error, as does replacing the contents of VectorTypeConstructor and TypeReference with a literal (e.g. 'test'). However that removes functionality from the grammar which is obviously unacceptable

Using assignments by changing to

({TypeReference.type = current} | {VectorTypeConstructor.type = current})

changes the error to the lines containing 'type = [TypeDecl]', with the text 'A feature 'type' with a different cardinality or containment configuration already exists in type 'VectorTypeConstructor/TypeReference''.

Im not very familiar with Xtext, so any help would be greatly appreciated!

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Re: Unassigned Rule Calls - 'current' already created [message #1822595 is a reply to message #1822587]

Tue, 10 March 2020 10:54

Christian Dietrich

Messages: 14665
Registered: July 2009

Senior Member

Hmmm

Maybe you can add the immutable to the two rules instead

Twitter : @chrdietrich
Blog : https://www.dietrich-it.de

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Re: Unassigned Rule Calls - 'current' already created [message #1822611 is a reply to message #1822595]

Tue, 10 March 2020 13:36

Rob K

Messages: 5
Registered: January 2020

Junior Member

Christian Dietrich wrote on Tue, 10 March 2020 10:54

Hmmm

Maybe you can add the immutable to the two rules instead

It works! however, this solution requires copy/pasting code, something I obviously would prefer to avoid!

So if anyone has an even better solution I would love to hear it

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