# Bubblewrap
Fork of `MonEx`, simplifying the types to be idiomatic Elixir.
Bubblewrap implements two most common monadic data types:
- `Bubblewrap.Result` - container for a result of operation or error.
Where the underlying structure is a tuple: `{:ok, value}` or `{:error, e}` respectively.
- `Bubblewrap.Option` - container for a value that might be present or missing.
It is a simple wrapper around a value that could be `nil`.
- `Bubblewrap` - collection of utility functions to work with both of these types.
## Result
Result type fits perfectly with idiomatic Erlang/Elixir return values.
When some library function returns either `{:ok, val}` or `{:error, err}`,
you can use functions provided by Bubblewrap right away. The most typical example,
where Bubblewrap shines, is a pipeline, where each operation can fail. Normally
this would be organized in a form of nested case expressions:
final = case op1(x) do
{:ok, res1} ->
case op2(res1) do
{:ok, res2} -> op3(res2)
{:error, e} -> {:error, e}
end
{:error, e} -> {:error, e}
end
With Bubblewrap you can do the same using `flat_map` operation:
final = op1(x) |> flat_map(&op2/1) |> flat_map(&op3/1)
Once any of the operations returns `{:error, e}`, following operations
are skipped and the error is returned. You can either do something
based on pattern matching or provide a fallback (can be a function or a default value).
case final do
{:ok, value} -> IO.puts(value)
{:error, e} -> IO.puts("Oh, no, the error occured!")
end
final |> fallback({:ok, "No problem, I got it"})
## Option
Option type is just an alias for `t() | nil`. With Option type, you can use the
same set of functions, such as `map`, `flat_map`, etc.
find_user(id)
|> map(&find_posts_by_user/1)
This will only request for posts if the user was found.
See docs per Result and Option modules for details. [docs](https://hexdocs.pm/bubblewrap/api-reference.html).
## Installation
The package can be installed as:
1. Add `bubblewrap` to your list of dependencies in `mix.exs`:
```elixir
def deps do
[{:bubblewrap, "~> 0.2.2"}]
end
```