How can I create a goto expression in xtext?

Question

I want to create a goto expression as follows

//label
 <bb 2> :

//goto
goto <bb 2>;

The following grammar works fine for a simple ID. I have no idea how to reference the <ID INT> in the goto expression.

Goto returns Goto:
    {Goto}
    'goto' goto+=[Label]  ';'
;

LabelDef returns LabelDef:
    {LabelDef}
    label+= Label ':'
    ;

Label returns Label:
    {Label}
    name= ID
    ;

Do have any idea how to that?

score 1 · Accepted Answer · answered Nov 30 '21 at 14:15

1

the feature you are looking for is a DataType rule

Goto returns Goto:
    {Goto}
    'goto' goto+=[Label|IDandINT]  ';'
;

LabelDef returns LabelDef:
    {LabelDef}
    label+= Label ':'
    ;

Label returns Label:
    {Label}
    name= IDandINT
    ;
IDandINT: ID INT;

you may also introduce / customize DefaultTerminalConverters/IValueConverter for the datatype rule to normalize whitespace

answered Nov 30 '21 at 14:15

Christian Dietrich

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Thank you for your answer, when generating I wasn't having the result I was looking for because of xtext. I discovered that when I created a new project. The following sub-grammar works fine. `Goto returns Goto: {Goto} 'goto' goto = [Label|QualifiedName] ';' '[INV]' ; LabelDef returns LabelDef: {LabelDef} name = Label ; Label returns Label: {Label} name = QualifiedName ':' ; QualifiedName: '<' ID INT '>' ; ` – Soulimane Kamni Dec 08 '21 at 14:32

score 0 · Answer 2 · answered Nov 30 '21 at 09:55

I think you want a terminal that is essentially "ID INT" and then use it to crossreference your Label. I think this is going to be a lot of work just to be able to allow "spaces" in your labels. Why not simply rely on terminal "ID" and users may name them "bb2" if they wish?

How can I create a goto expression in xtext?

2 Answers2