http://scriptasylum.com/tutorials/infix_postfix/infix_postfix.html

A^B+(C+D(E-F)-G)*H
AB^CDEF-+G-H*+


A*B-C+(D^E*F)+(G*H)


A+B*(C^D-(E/F)/G)^H



// EX: a+(b*c+d)-f/g^h


1.1( A + B * ( C - D ) ) / E 
A B C D - * + E /

1.2A + B * C / D - E
A B C * D / + E -