Left Recursion: ANTLR

Question

I am trying to do Lexical Analysis in Java grammar, but got stack in that error. I am in expression part right now, doing it in parts (just using string_expression):

expression:
    ( expression8)
;

expression8:
    {Expression8Action}
    ((  
      ( "+" 
      | "+=" ) 
      e2=expression )e1=expression8)?
;

Answer 1

Solved with turning on backtrack (file .mwe2):

language = StandardLanguage {
        name = "org.xtext.example.mydsl.MyDsl"
        fileExtensions = "mydsl"

        serializer = {
            generateStub = false
        }
        validator = {
            // composedCheck = "org.eclipse.xtext.validation.NamesAreUniqueValidator"
        }
        parserGenerator = {
            options = {
                backtrack = true
            }
        }
    }