Expression parsing

token term { <variable> | <number> | \( <expression> \) }
token unaryop { \+ | - }
token mulop { \* | / }
token addop { \+ | - }
token cmpop { == | \<= | \< | \> | =\> }
token andop { \&\& }
token orop  { \|\| | \^\^ }

rule powterm { <term> [ \*\* <term> ]* }
rule unaryterm { <unaryop>? <powterm> }
rule multerm { <unaryterm> [ <mulop> <unaryterm> ]* }
rule addterm { <multerm> [ <addop> <multerm> ]* }
rule cmpterm { <addterm> [ <cmpop> <addterm> ]* }
rule andterm { <cmpterm> [ <andop> <cmpterm> ]* }
rule expression  { <andterm> [ <orop> <andterm> ]* }

This gets very tedious. It's also very slow to parse.