README.md

try

An experimental error handling library.

Supported Architectures

• amd64
• arm64

Usage

This is a simple example.

import (
	"net/url"
	"os"

	"github.com/lufia/try"
)

func Run(file string) (string, error) {
	cp, err := try.Handle()
	if err != nil {
		return "", err
	}
	s := try.Check1(os.ReadFile(file))(cp)
	u := try.Check1(url.Parse(string(s)))(cp)
	return u.Path, nil
}

try.Handle creates a fallback point, called "checkpoint", then return nil error at the first time.

After that, above code calls os.ReadFile and url.Parse with try.Check1. If either these functions returns an error, try.Check1 rewind the program to the checkpoint, then try.Handle will return the error.

I strongly recommend that Check and Handle should call on the same stack.

Example

Error handling in Go sometimes gets flustrated. For instance:

func GetAlerts(w http.ResponseWriter, r *http.Request) {
	if err := r.ParseForm(); err != nil {
		http.Error(w, err.Error(), http.StatusBadRequest)
		return
	}
	orgID, err := strconv.Atoi(r.Form.Get("orgId"))
	if err != nil {
		http.Error(w, err.Error(), http.StatusBadRequest)
		return
	}
	alerts, err := repository.FetchAlerts(orgID)
	if err != nil {
		http.Error(w, err.Error(), http.InternalServerError)
		return
	}
	body, err := json.Marshal(alerts)
	if err != nil {
		http.Error(w, err.Error(), http.InternalServerError)
		return
	}
	...
}

The example above can rewrite more simple with try.

func GetAlerts(w http.ResponseWriter, r *http.Request) {
	cp400, err := try.Handle()
	if err != nil {
		http.Error(w, err.Error(), http.StatusBadRequest)
		return
	}
	cp500, err := try.Handle()
	if err != nil {
		http.Error(w, err.Error(), http.InternalServerError)
		return
	}

	try.Raise(r.ParseForm())(cp400)
	orgID := try.Check1(strconv.Atoi(r.Form.Get("orgId")))(cp400)
	alerts := try.Check1(repository.FetchAlerts(orgID))(cp500)
	body := try.Check1(json.Marshal(alerts))(cp500)
	...
}