XText: first and last character truncated in custom STRING terminals-Collection of common programming errors

If you customize the STRING rule, you’ll have to adapt the respective value converter, too.

Something like this has to be bound in your runtime module:

public class MyStringValueConverter extends STRINGValueConverter {

    @Override
    protected String toEscapedString(String value) {
        return value;
    }

    public String toValue(String string, INode node) {
        if (string == null)
            return null;
        return string;
    }
}

See the docs for details.