I propose a addition to current try proposal to enable optional error
wrapping.
demo codes:
package main
import (
"fmt"
"io"
"os"
)
// wrapErr is an error wrapping function
func wrapErr(err error, format string, args ...interface{}) error {
return fmt.Errorf(
"%s: %s",
fmt.Sprintf(format, args...),
err.Error(),
)
// or other error implementation
}
// like the proposed try function but with custom wrapper
var try = makeTry(wrapErr)
// use like the proposed try with extra wrapping arguments
func CopyFile(src, dest string) (err error) {
r := try(os.Open(src), "open %s", src)
// if there is an error, it will be "open <src>: <err>" as returned by
wrapErr
defer r.Close()
w := try(os.Create(dest), "create %s", dest)
defer func() {
w.Close()
if err != nil {
os.Remove(dest)
}
}()
try(io.Copy(w, r)) // bare try without arguments, so no wrapping
try(w.Close())
return nil
}
Actually I have implemented this by abusing panic/recover.
Implementation: https://github.com/reusee/e/blob/master/error.go#L16
Example: https://github.com/reusee/e/blob/master/example_test.go#L15
I've been using this for a while. It works well to serve its purpose
although bring in a little more overhead of panic/recover.
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