| errors | Package errors implements functions to manipulate errors. |
| fmt | Package fmt implements formatted I/O with functions analogous to C's printf and scanf. |
| github.com/spf13/pflag | Package pflag is a drop-in replacement for Go's flag package, implementing POSIX/GNU-style --flags. |
| math/big | Package big implements arbitrary-precision arithmetic (big numbers). |
| regexp | Package regexp implements regular expression search. |
| speter.net/go/exp/math/dec/inf | |
| strconv | Package strconv implements conversions to and from string representations of basic data types. |
| strings | Package strings implements simple functions to manipulate UTF-8 encoded strings. |