README.md

go-thrower

Package go-thrower implements a simple throw/catch exception wrapper around panic. It catches its own panics, but lets the others through.

Functions

func RecoverError(err *error)

RecoverError catches a thrown error. The pointer passed in can be nil if you don't care what the thrown error was.

Use it as follows:

    func doSomething() (err error) {
      // This will catch thrown errors and set the return value to the thrown error.
      defer thrower.RecoverError(&err)
      // Do some things that might call thrower.Throw() eventually.
      // For example:
      r := somethingThatCanReturnError()
      thrower.ThrowIfError(r)  // If not nil, 'r' becomes the function's return value
    }

For functions that don't return an error, you can wrap the code in another function to retrieve the error and do something useful with it:

    func returnsNoError() {
      // This will catch thrown errors and set the return value to the thrown error.
      getErr := func() (err error) {
        defer thrower.RecoverError(&err)
        // Do some things that might call thrower.Throw() eventually.
        // For example:
        r := somethingThatCanReturnError()
        thrower.ThrowIfError(r)  // If not nil, 'r' becomes the function's return value
        return nil
      }
      err := getErr()
      if err != nil {
        fmt.Println("We got an error", err)
      }
    }

func SetCatching(state CatchState) CatchState

SetCatching sets whether or not thrown errors get caught and returns the previous value. Passing in DontCatch will prevent thrown errors from being caught. They will become just regular panics. Do not use this in production code; it is for debugging only. It is against Go style to let panics cross API boundaries. All thrown errors should be caught by RecoverError normally.

func Throw(err error)

Throw throws the given error, which should be caught by RecoverError normally.

func ThrowIfError(err error)

ThrowIfError throws an error only if err is not nil.