https://github.com/sirkon/go-oneof
Struct into oneof generator
https://github.com/sirkon/go-oneof
Last synced: 3 months ago
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Struct into oneof generator
- Host: GitHub
- URL: https://github.com/sirkon/go-oneof
- Owner: sirkon
- License: mit
- Created: 2020-02-23T09:28:39.000Z (over 5 years ago)
- Default Branch: master
- Last Pushed: 2020-03-08T11:52:39.000Z (about 5 years ago)
- Last Synced: 2024-06-20T15:51:43.808Z (12 months ago)
- Language: Go
- Size: 12.7 KB
- Stars: 4
- Watchers: 1
- Forks: 0
- Open Issues: 0
-
Metadata Files:
- Readme: README.md
- License: LICENSE
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README
# go-oneof
This tool is aimed to generate a Go code to partially replicate lacking discriminated unions functionality in Go
Installation
```shell script
GO111MODULE=on go get github.com/sirkon/go-oneof
```
## How to use it
Need to write a special structure with name staring from `oneof` (there are further limitations, but they will be
reported by the utility itself). Like this:
```go
// node.go file
package node
//go:generate go-oneof node.go
type oneofNode struct {
Value string
OperatorSum struct {
Left *oneofNode
Right *oneofNode
}
}
```
And run `go generate` over it
The result will be
```go
package node
//go:generate go-oneof node.go
type oneofNode struct {
Value string
OperatorSum struct {
Left *oneofNode
Right *oneofNode
}
}
// Node an interface to limit available implementations to emulate discriminated union type
type Node interface {
isNode()
}
// Value branch of Node
type Value string
func (Value) isNode() {}
// OperatorSum branch of Node
type OperatorSum struct {
Left Node
Right Node
}
func (OperatorSum) isNode() {}
```
Some notes:
* type `oneofName` will generate interface `Name` with private method `isName`
* each field causes an implementation of generated `Name`
* comments existed in the source file will disappear in its replacement
* free comments will stay, but will be moved on the top of the file
* You may use `--pointer` or `-p` call parameter to implement `Name` of source struct fields over pointer to these
structs, not structs themselves, i.e. `Node` implementation for `OperatorSum` would be
```go
func (*OperatorSum) isNode()
```
in this example
* This source file may have errors like reference to entities that do not exists. This may work for self reference, but
the usage of `*oneofNode` (change to actual name) is preferable.