Yes, With ANTLR Studio you can step over your grammar rules just as you debug your java program! No more separately debugging your grammar files. You can even step in/out of rules just like you do so with java methods.
Step through your java code inside grammar files as you normally would in your java files.
Watch Live Parse Trees and ASTs being built as you step through your grammar. And all this without any change to your code.
Watch the text input to your parser/lexer getting parsed as you step through your grammar. And this functionality without any changes to the code on your part.