data>>> 4
=====> Trying <grammar> from position 0
4\n    |...Trying <Answer>
       |   |...Trying subpattern /\d+/
\n     |   |    \_____subpattern /\d+/ matched '4'
ANSWER called
       |    \_____<Answer> matched '4'
--> processed
data>>> .4
=====> Trying <grammar> from position 0
.4\n   |...Trying <Answer>
       |   |...Trying subpattern /\d+/
       |   |    \FAIL subpattern /\d+/
       |    \FAIL <Answer>
        \FAIL <grammar>
=====> Trying <grammar> from position 1
4\n    |...Trying <Answer>
       |   |...Trying subpattern /\d+/
\n     |   |    \_____subpattern /\d+/ matched '4'
       |    \_____<Answer> matched '4'
--> 4
data>>>