Option 1 means `catch exception` gt `put it in a R

Question

< travis> Option 1 means `catch exception` gt `put it in a Result` gt `rethrow another the same exception` so definitely Option 2

travis · Answer

What if the underlying library that the `Api` will be using captures exceptions itself to return specific result codes They are already doing `catch exception` `return as result code` Does that change how I should approach it

travis · Answer

i e doesn t option 1 allow the user of `Api` to never have to deal with exceptions as the only time exceptions are thrown are when they use the extension functions

travis · Answer

just playing devils advocate I m leaning towards option 2 just wanted to get feedback to make sure I m not overlooking something

Andreas Sinz · Answer

the question is do these methods have to use the other version of itself If the `Api` already returns an error code you could just create two methods `getData` returns the data or throws an exception and `getDataAsResult` that calls the same `Api` but returns a `Result`

Andreas Sinz · Answer

just make sure that a method just has one thing to do that improves the reusability

Andreas Sinz · Answer

contrived example ``` Returns an Int as error Code or String as Data fun Api readData Any throws MyException fun MyApi readData String val data = Api readData if data is Int throw MyException data return data as String fun MyApi readDataAsResult Result lt String gt val data = Api readData return if data is Int Result Error data else Result Success data as String ```

travis · Answer

Hmm interesting approach of splitting the responsibility between the extension functions Although wouldn t the `Any` return from the core function be more error prone

Andreas Sinz · Answer

and if you need to do something with `data` first just create another function ``` fun MyApi parseData Data val data = Api readData Do Work with Data return newData ``` and use this function inside `MyApi readData` and `MyApi readDataAsResult` instead of the original function

Andreas Sinz · Answer

that was just an example of an `Api` you are using that returns an error code or the actual data

travis · Answer

Ohhh

travis · Answer

The `data` amp `responseCode` actually comes back as separate parameters in a callback so I have to luxury of deciding how to package it

Andreas Sinz · Answer

I just wanted to highlight that its not necessary that `MyApi readData` calls `MyApi readDataAsResult` or vice versa

travis · Answer

I see

Andreas Sinz · Answer

i think I get what you are talking about you mean the data flows like that `Api` gt `core` gt `Extension methods`

travis · Answer

Yup

travis · Answer

Or that is where I was going with it thus far

Andreas Sinz · Answer

right and if you d get an error code from `Api` you d `throw exception based on error code` gt `catch excetpion` gt `return result`

travis · Answer

For option 2 yes

travis · Answer

Whereas with option 1 I d package the `data` amp result code in `Result` and only throw via extension function `Result based on error code` gt `return result` gt optional use of extension `throw exception`

Andreas Sinz · Answer

is it necessary to distinguish between `core` and `extension method`

Andreas Sinz · Answer

or lets say having `readData` and `readDataAsResult` inside core

travis · Answer

Both methods could certainly be inside the core `Api` class if that s what you mean

travis · Answer

I was having some of the Api split into extension to make it an optional module that people could import

travis · Answer

To keep the core Api simple and minimalistic but optionally add convenience extensions

travis · Answer

So I guess the question is is an API easier to use if it throws or returns a `Result` as it s default i e pre extension function impl

Andreas Sinz · Answer

if the `Api` returns more often an error code than it throws I d use Option 1 otherwise Option 2 just to have as little overhead as possible

Andreas Sinz · Answer

you won t be able to remove all overhead if you split the code into `core` and `extensions` and the `Api` doesn t have consistent return types sometimes throws sometimes returns error codes

travis · Answer

Awesome very insightful Thanks