Extract a string representation of Go type

Motivations

For the samber/do project, I needed to convert a Go type into a string. I used to convert it with fmt.Sprintf("%T", t) -> mypkg.MyStruct, but it does not insert package path into type representation, leading to collision when types from different pacakges match.

This package export type using the following representation:

  *[]**<-chan   github.com/samber/example    .Example
  |             |                            ^
  |             |                            Type name
  |             ^
  |             The package path (including package name)
  ^
  Type indicators (map, slice, pointer, channel...)

This library supports:

• primitive types
• pointers
• structs
• functions with input and output
• vaargs
• interfaces
• maps
• arrays
• slices
• channels
• generics
• anonymous types
• named types

Known limitations:

• structs in anonymous types
• structs in generic type
• any("foobar") is currently reported as any instead of string (see #2)

Examples

Using the following types:

package example

type testStruct struct{}
type testGeneric[T any] struct{ t T }
type testNamedType testStruct

Type	Exported
int	int
*int	*int
**[]*int	**[]*int
**[]*map[int]bool	**[]*map[int]bool
func (a string, b bool) int	func (string, bool) int
func(int, ...string) (bool, error)	func(int, ...string) (bool, error)
testStruct	github.com/samber/example.testStruct
*testStruct	*github.com/samber/example.testStruct
***testStruct	***github.com/samber/example.testStruct
***testNamedType	***github.com/samber/example.testNamedType
[][3]***testStruct	[][3]***github.com/samber/example.testStruct
testGeneric[string]	github.com/samber/example.testGeneric[string]
*map[testStruct]chan<- testGeneric[string]	*map[github.com/samber/example.testStruct]chan<- github.com/samber/example.testGeneric[string]

See more examples here

🚀 Install

go get github.com/samber/go-type-to-string

This library is v1 and follows SemVer strictly. No breaking changes will be made to exported APIs before v2.0.0.

💡 How to

GoDoc: https://pkg.go.dev/github.com/samber/go-type-to-string

package example

import converter "github.com/samber/go-type-to-string"

type Example struct{
    foo string
    bar int
}

func main() {
    name1 := converter.GetType[*Example]()
    // "*github.com/samber/example.Example"

    name2 := converter.GetValueType(Example{})
    // "github.com/samber/example.Example"
}

🤝 Contributing

• Ping me on Twitter @samuelberthe (DMs, mentions, whatever :))
• Fork the project
• Fix open issues or request new features

Don't hesitate ;)

# Install some dev dependencies
make tools

# Run tests
make test
# or
make watch-test

👤 Contributors

💫 Show your support

Give a ⭐️ if this project helped you!

📝 License

Copyright © 2023 Samuel Berthe.

This project is MIT licensed.