https://github.com/muir/reflectutils
Golang utility functions for working with reflection
https://github.com/muir/reflectutils
go golang reflection-library
Last synced: 7 months ago
JSON representation
Golang utility functions for working with reflection
- Host: GitHub
- URL: https://github.com/muir/reflectutils
- Owner: muir
- License: mit
- Created: 2021-10-24T05:44:39.000Z (about 4 years ago)
- Default Branch: main
- Last Pushed: 2025-05-05T19:56:49.000Z (7 months ago)
- Last Synced: 2025-05-05T20:45:20.682Z (7 months ago)
- Topics: go, golang, reflection-library
- Language: Go
- Homepage:
- Size: 55.7 KB
- Stars: 8
- Watchers: 1
- Forks: 1
- Open Issues: 3
-
Metadata Files:
- Readme: README.md
- License: LICENSE
- Codeowners: .github/CODEOWNERS
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README
# reflectutils - utility functions for working with Golang's reflect package
[](https://pkg.go.dev/github.com/muir/reflectutils)
[](https://goreportcard.com/report/github.com/muir/reflectutils)
[](https://codecov.io/gh/muir/reflectutils)
Install:
go get github.com/muir/reflectutils
---
Reflectutils is simply a repository for functions useful for working with Golang's reflect package.
Here's the highlights:
## Walking structures
```go
func WalkStructElements(t reflect.Type, f func(reflect.StructField) bool)
```
Recursively walking a struct with reflect has a pitfalls:
1. It isn't recurse with respect to embeded structs
1. The `Index` field of `reflect.Structfield` of embedded structs is not relative to your starting point.
[WalkStructElements()](https://pkg.go.dev/github.com/muir/reflectutils#WalkStructElements) walks
embedded elements and it updates `StructField.Index` so that it is
relative to the root struct that was passed in.
## Setting elements
```go
func MakeStringSetter(t reflect.Type, optArgs ...StringSetterArg) (func(target reflect.Value, value string) error, error)
```
[MakeStringSetter()](https://pkg.go.dev/github.com/muir/reflectutils#MakeStringSetter)
returns a function that can be used to assing to `reflect.Value` given a
string value. It can handle arrays and slices (splits strings on commas).
## Parsing struct tags
Use [SplitTag()](https://pkg.go.dev/github.com/muir/reflectutils#SplitTag) to break a struct
tag into it's elements and then use [Tag.Fill()](https://pkg.go.dev/github.com/muir/reflectutils#Tag.Fill)
to parse it into a struct.
For example:
```go
type TagInfo struct {
Name string `pt:"0"` // positional, first argument
Train bool `pt:"train"` // boolean: true: "train", "train=true"; false: "!train", "train=false"
Count int `pt:"count"` // integer value will be parsed
}
st := reflect.StructTag(`foo:"bar,!train,count=9"`)
var tagInfo TagInfo
err := GetTag(st, "foo").Fill(&tagInfo)
// tagInfo.Name will be "bar"
// tagInfo.Train will be false
// tagInfo.Count will be 9
```
## Type names
The `TypeName()` function exists to disambiguate between type names that are
versioned. `reflect.Type.String()` will hides package versions. This doesn't
matter unless you've, unfortunately, imported multiple versions of the same
package.
## Default filler
The `FillInDefaultValues()` function will look at for a struct tag named "default"
and use that value to fill in values where no value has been set.
## Development status
Reflectutils is used by several packages. Backwards compatability is expected.