We're not talking about parsing in base 10, we're talking about parsing in base 8. I need to be able to tell if the parse succeeded or not, silently hiding errors is bad. The correct behaviour demonstrated in perl and python:

    $ perl -le 'print 07'
    7
    $ perl -le 'print 08'
    Illegal octal digit '8' at -e line 1, at end of line
    Execution of -e aborted due to compilation errors.
    $ python -c 'print 07'
    7
    $ python -c 'print 08'
      File "", line 1
        print 08
       	^
    SyntaxError: invalid token