Your grammer doesn't allow a statement to contain a calculation, where a calculation is 4+8 let's say.
So, after it consumes the 4+8 it has no way to know what to
do with the +5 part. Also as an asside, you have all the math operators at the same precedence...so you'll end up wandering later why 2+4*5 = 30 and not 22 :)
The grammer for parsing standard algebra is a pretty common example for teaching parsing. (Give me a sec to dig up a link for an example) :)
<update style="big">
Complete example (almost) taken straight from the "Dragon" compiler book. Page 259
expression: expression '+' term
| expression '-' term
| term
term: term '*' factor
| term '/' factor
| factor
factor: '(' expression ')'
| /\d+/
I'm sorry I don't have time to explain exactly how it works, but I can tell you how to figure that out. Turn on tracing as you have, and watch as many examples as you can and pay close attention to HOW Parse::RecDescent walks this grammer and your input.
/\/\averick
perl -l -e "eval pack('h*','072796e6470272f2c5f2c5166756279636b672');"