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Writing java-style If statements in XText results in an error [message #1810536]

Tue, 13 August 2019 09:46

Jakob Sachs

Messages: 15
Registered: May 2018

Junior Member

I'm writing a custom Xtext editor for my own DSL-Language and now want to add If-Statements to my language.
The Statements look something like this:

if (TRUE) {
    (...)
}

But when I try adding them in, I get an error "A class may not be a super type of itself".

This is my code so far:

grammar XtextTest with org.eclipse.xtext.common.Terminals

generate xtextTest "http://www.my.xtext/Test"

Model:
	statements+=Statement*;

Statement:
	VariableAssignment |
	IfStatement;

IfStatement:
	'if' '(' BooleanExpression ')' '{' Statement '}';
	
BooleanExpression:
	'TRUE' | 'FALSE';

VariableAssignment:
	name=ID "=" INT ';';

How can I implement this? Or am I doing something obviously wrong?

Any help is appreciated ^^

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Re: Writing java-style If statements in XText results in an error [message #1810540 is a reply to message #1810536]

Tue, 13 August 2019 10:09

Christian Dietrich

Messages: 14665
Registered: July 2009

Senior Member

hi, assignments are a important thing in Xtext. if you just call rules without assigning them it influences the supertype hierarchy that is inferred. => it is better to change the grammar to

IfStatement:
'if' '(' condition=BooleanExpression ')' '{' statement=Statement '}';

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

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