I think Either's handle this really well (and in fact this is more or less how its done with ErrorMonads). You basically return Either Value [Error], which has

I think Either's handle this really well (and in fact this is more or less how its done with ErrorMonads). You basically return Either Value [Error], which has the benefit of being much more compassable than something that breaks control-flow like try/catch. For example, if you have something like x = emptyStringOnDoesntExist(read(path)) // "" on not exist error BUT NOT permission error x = emptyStringOnAnyError(read(path)) // "" on any error So right now this doesn't seem THAT different than using try/catch to select values depending on the type of error "thrown". But its critical to notice that we are going through normal programming control flow here (we pass in the result value, not some sort of weird function wrapper function that wraps read and inserts a try/catch). This becomes much more apparent how its useful when you have more interesting tasks: var filenames = [..,...,..]; var concated = filenames.reduce(pipe(read, emptyStringOnDoesntExist, concat), ""); So now we've done something really neat: we are concating a bunch of files, and accepting some may not exist, BUT if any of them have a permission error the whole thing will return Either _ [PermissionError]. Now are errors are ACTUALLY composable.