yacc learning.
go get -d github.com/pocke/dentaku
cd $GOPATH/src/github.com/pocke/dentaku/parser
make
cd ..
go installecho '1+1' | dentaku # => 21+3 # => 4
2+0 # => 210-3 # => 7
5-10 # => -510*5 # => 5010/2 # => 5
14/6 # => 7/33*5+2*6 # => 27
3*(5+2)*6 # => 126