XSAM / optionGen

optinGen is an options generate tool for golang

optionGen

---

optionGen is a tool to generate go Struct option for test, mock or more flexible.

Installation

go get -u github.com/xsam/optionGen/cmd/optionGen

optionGen require goimports to format code which is generated. So you may confirm that goimports has been installed

go get golang.org/x/tools/cmd/goimports

Example

To generate struct option, you need write a function declaration to tell optionGen how to generate. function Name consists of "_" prefix, struct name and "OptionDeclaration" suffix. In this function, just return a variable which type is map[string]interface{}.

The key of the map means option name, and the value of the map should consist of two parts, one for option type(except func type), and the other option default value.

Looks like this:

"sounds": string("Meow")
"food":   (*string)(nil)
// function type is special
"Walk":   func() {
	log.Println("Walking")
}

A Cat struct option declaration may like this:

func _CatOptionDeclaration() interface{} {
	return map[string]interface{}{
		"sounds": string("Meow"),
	}
}

Once you finished you declaration. You can add this line in your code

//go:generate optionGen

and use go generate command to generate option.

Here is the sample result generate by optionGen

package main

import "log"

type CatOptions struct {
	sounds string
}

type CatOp func(option *CatOptions)

func CatOpWith_sounds(value string) CatOp { return func(option *CatOptions) { option.sounds = value } }

func _NewCatOptions() CatOptions {
	return CatOptions{
		sounds: "Meow",
	}
}

To use the generated code. you could add Options struct to your struct

type Cat struct {
	options CatOptions
}

And write a new function

func NewCat(option ... CatOp) *Cat {
	cat := Cat{
		options: _NewCatOptions(),
	}

	for _, op := range option {
		op(&cat.options)
	}
	return &cat
}

For more example. see the example folder

Enjoy!