pl@nereida:~/Lperltesting$ ./calc510withactions4.pl
2-8/4/2-1
rt -> empty
term-> digits(2) rt
rt -> empty
rt -> [*/] digits(2) rt
rt -> [*/] digits(4) rt
term-> digits(8) rt
rt -> empty
term-> digits(1) rt
re -> empty
re -> [+-] term re
re -> [+-] term re
exp -> term re
matches: 2-8/4/2-1
Stack=(2 8 4 / 2 / - 1 -)