# Forensic
[](https://hex.pm/packages/forensic)
Handling monads `{:ok, result}` and `{:error, description}` can be very tricky in a complex systems.
Moreover, it is very difficult to track the history of the error and it's influence. Unfortunately there are no built-in tools for that.
Forensic is pass-through error protocol and a set of macros, aimed to sctructurally register the description of the error in the context, where it had occured and collect all the collateral errors.
Forensic's protocol fully follows `{:error, description}` ideology.
WARNING: Do not forget to `import Forensic`! `require Forensic` won't work!
`Forensic.error(error, description \\ :no_description, contents \\ nil)` will transparently incapsulate all {:error, description} or even any arbitary error given.
## Installation
```elixir
def deps do
[
{:forensic, "~> 0.2.2"}
]
end
```
## Concept
`Forensic.error(...)` returns the error tuple in the format:
```elixir
{:error,
%Forensic.Errors{
history: [
%Forensic.Error{
bindings: [],
contents: nil,
description: :no_description,
function: "test Forensic.Errors protocol detection/1",
module: ForensicTest
},
%Forensic.Error{
bindings: [],
contents: nil,
description: :no_description,
function: "test Forensic.Errors protocol detection/1",
module: ForensicTest
}
]
}}
```
## Usage
Basic scenario
```elixir
import Forensic
...
Forensic.error(error_to_describe)
...
```
The full-on scenario is:
```elixir
import Forensic
def Foo(some_var) do
with {:ok, result} <- Foo2(some_var) do
{:ok, result}
else
Forensic.last?(:error_signature) -> do_something_for_this_error_signature()
Forensic.last?(:error_signature_2) = error -> do_something_for_this_error_signature2()
# Register unrecoverable error afterwards
Forensic.error(error, :error_description2)
error -> Forensic.error(error, :error_description)
end
end
```
`Forensic.last?(error)` extracts the last error description from like was in `{:error, description}` providing a way to handle different errors by their signatures as well.
## License
MIT
