| fmt | Package fmt implements formatted I/O with functions analogous to C's printf and scanf. |
| go/ast | Package ast declares the types used to represent syntax trees for Go packages. |
| go/format | Package format implements standard formatting of Go source. |
| go/parser | Package parser implements a parser for Go source files. |
| go/token | Package token defines constants representing the lexical tokens of the Go programming language and basic operations on tokens (printing, predicates). |
| go/types | Package types declares the data types and implements the algorithms for type-checking of Go packages. |
| golang.org/x/tools/go/analysis | Package analysis defines the interface between a modular static analysis and an analysis driver program. |
| golang.org/x/tools/go/analysis/passes/internal/analysisutil | Package analysisutil defines various helper functions used by two or more packages beneath go/analysis. |
| log | Package log implements a simple logging package. |
| os | Package os provides a platform-independent interface to operating system functionality. |
| strconv | Package strconv implements conversions to and from string representations of basic data types. |