# Recode
[](https://hex.pm/packages/recode)
[](https://github.com/hrzndhrn/recode/actions)
[](https://github.com/hrzndhrn//blob/main/LICENSE.md)
A linter with autocorrection.
`recode` is an experimental project to play around with the great
[`sourceror`](https://github.com/doorgan/sourceror) package by @doorgan.
This library is still under development, breaking changes are expected.
The same is true for `sourceror` and most of `recode`'s functionality is based
on `sourceror`.
`recode` can correct and check the following things:
```sh
> mix recode.help
Design tasks:
TagFIXME # Checker - Checks if there are FIXME tags in the sources.
TagTODO # Checker - Checks if there are TODO tags in the sources.
Readability tasks:
AliasExpansion # Corrector - Exapnds multi aliases to separate aliases.
AliasOrder # Corrector - Checks if aliases are sorted alphabetically.
EnforceLineLength # Corrector - Forces expressions to one line.
Format # Corrector - Does the same as `mix format`.
PipeFunOne # Corrector - Add parentheses to one-arity functions.
SinglePipe # Corrector - Pipes should only be used when piping data through multiple calls.
Specs # Checker - Checks for specs.
Refactor tasks:
FilterCount # Corrector - Checks calls like Enum.filter(...) |> Enum.count().
Nesting # Checker - Checks code nesting depth in functions and macros.
Warning tasks:
Dbg # Corrector - There should be no calls to dbg.
IOInspect # Corrector - There should be no calls to IO.inspect.
TestFileExt # Corrector - Checks the file extension of test files.
UnusedVariable # Corrector - Checks if unused variables occur.
```
It is also possible to run `recode` in a none-autocorrect mode to just lint your
code.
## Installation
The package can be installed by adding `recode` to your list of dependencies
in `mix.exs`:
```elixir
def deps do
[
{:recode, "~> 0.6", only: :dev}
]
end
```
`Recode` requires Elixir 1.13.0 or higher. If you add `recode` to a project that
supports lower Elixir versions you could add recode as following:
```elixir
def deps do
[
# your deps
] ++ recode()
end
defp recode() do
case Version.match?(System.version(), "~> 1.13") do
true -> [{:recode, "~> 0.4", only: :dev}]
false -> []
end
end
```
Documentation can be found at [https://hexdocs.pm/recode](https://hexdocs.pm/recode).
## Usage
To start with `recode` a configuration file is needed.
```sh
mix recode.gen.config
```
This mix task generates the config file `.recode.exs`.
```elixir
[
version: "0.6.0",
# Can also be set/reset with `--autocorrect`/`--no-autocorrect`.
autocorrect: true,
# With "--dry" no changes will be written to the files.
# Can also be set/reset with `--dry`/`--no-dry`.
# If dry is true then verbose is also active.
dry: false,
# Can also be set/reset with `--verbose`/`--no-verbose`.
verbose: false,
# Can be overwritten by calling `mix recode "lib/**/*.ex"`.
inputs: ["{mix,.formatter}.exs", "{apps,config,lib,test}/**/*.{ex,exs}"],
formatter: {Recode.Formatter, []},
tasks: [
# Tasks could be added by a tuple of the tasks module name and an options
# keyword list. A task can be deactivated by `active: false`. The execution of
# a deactivated task can be forced by calling `mix recode --task ModuleName`.
{Recode.Task.AliasExpansion, []},
{Recode.Task.AliasOrder, []},
{Recode.Task.Dbg, [autocorrect: false]},
{Recode.Task.EnforceLineLength, [active: false]},
{Recode.Task.FilterCount, []},
{Recode.Task.Nesting, []},
{Recode.Task.PipeFunOne, []},
{Recode.Task.SinglePipe, []},
{Recode.Task.Specs, [exclude: "test/**/*.{ex,exs}", config: [only: :visible]]},
{Recode.Task.TagFIXME, [exit_code: 2]},
{Recode.Task.TagTODO, [exit_code: 4]},
{Recode.Task.TestFileExt, []},
{Recode.Task.UnusedVariable, [active: false]}
]
]
```
If a configuration file already exists, you can use the mix task
```sh
mix recode.update.config
```
to update the configuration file.
### `mix recode`
This mix task runs the linter with autocorrection. The switch `--dry` (alias
`-d`) prevents the update of the files and shows all changes in the console.
```
> cd examples/my_code
> mix recode --dry
Found 13 files, including 2 scripts.
...........................................................................................
File: lib/my_code.ex
[Specs 15/3] Functions should have a @spec type specification.
File: lib/my_code/alias_expansion.ex
Updates: 1
Changed by: AliasExpansion
1 1 |defmodule MyCode.AliasExpansion do
2 - | alias MyCode.{PipeFunOne, SinglePipe}
2 + | alias MyCode.PipeFunOne
3 + | alias MyCode.SinglePipe
3 4 |
4 5 | def foo(x) do
...|
[Specs 5/3] Functions should have a @spec type specification.
File: lib/my_code/alias_order.ex
Updates: 2
Changed by: AliasOrder, AliasExpansion
...|
12 12 |
13 13 |defmodule Mycode.AliasOrder do
14 - | alias MyCode.SinglePipe
14 + | alias MyCode.Echo
15 + | alias MyCode.Foxtrot
15 16 | alias MyCode.PipeFunOne
16 - | alias MyCode.{Foxtrot, Echo}
17 + | alias MyCode.SinglePipe
17 18 |
18 19 | @doc false
...|
File: lib/my_code/fun.ex
Updates: 1
Changed by: Format
...|
2 2 | @moduledoc false
3 3 |
4 - |
5 - |
6 - |
7 - |
8 - |
9 4 | def noop(x), do: x
10 5 |end
...|
File: lib/my_code/multi.ex
Updates: 2
Changed by: SinglePipe, PipeFunOne
...|
7 7 |
8 8 | def pipe(x) do
9 - | x |> double |> double()
9 + | x |> double() |> double()
10 10 | end
11 11 |
12 12 | def single(x) do
13 - | x |> double()
13 + | double(x)
14 14 | end
15 15 |
...|
File: lib/my_code/pipe_fun_one.ex
Updates: 1
Changed by: PipeFunOne
...|
5 5 |
6 6 | def pipe(x) do
7 - | x |> double |> double()
7 + | x |> double() |> double()
8 8 | end
9 9 |end
...|
File: lib/my_code/same_line.ex
[Specs 2/3] Functions should have a @spec type specification.
File: lib/my_code/single_pipe.ex
Updates: 1
Changed by: SinglePipe
...|
5 5 |
6 6 | def single_pipe(x) do
7 - | x |> double()
7 + | double(x)
8 8 | end
9 9 |
10 - | def reverse(a), do: a |> Enum.reverse()
10 + | def reverse(a), do: Enum.reverse(a)
11 11 |end
12 12 |
File: test/my_code_test.exs
Updates: 1
Changed by: TestFileExt
Moved from: test/my_code_test.ex
Finished in 0.06 seconds.
```
The switch `--no-autocorrect` runs the linter without any file changes. In this
mode, all correctors are working as checkers.
```
> cd examples/my_code
> mix recode --no-autocorrect
Found 11 files, including 2 scripts.
.............................................................................
File: lib/my_code.ex
[Specs 15/3] Functions should have a @spec type specification.
File: lib/my_code/alias_expansion.ex
[AliasExpansion 2/3] Avoid multi aliases.
[Specs 4/3] Functions should have a @spec type specification.
File: lib/my_code/alias_order.ex
[AliasOrder 15/3] The alias `MyCode.PipeFunOne` is not alphabetically ordered among its group
[AliasOrder 16/3] The alias `MyCode` is not alphabetically ordered among its group
[AliasOrder 16/26] The alias `Echo` is not alphabetically ordered among its multi group
[AliasExpansion 16/3] Avoid multi aliases.
File: lib/my_code/fun.ex
[Format -/-] The file is not formatted.
File: lib/my_code/multi.ex
[PipeFunOne 9/7] Use parentheses for one-arity functions in pipes.
[Dbg 9/32] There should be no calls to dbg.
[SinglePipe 13/7] Use a function call when a pipeline is only one function long.
[FilterCount 22/12] `Enum.count/2` is more efficient than `Enum.filter/2 |> Enum.count/1`
[IOInspect 24/8] There should be no calls to IO.inspect.
File: lib/my_code/pipe_fun_one.ex
[PipeFunOne 7/7] Use parentheses for one-arity functions in pipes.
File: lib/my_code/single_pipe.ex
[SinglePipe 7/7] Use a function call when a pipeline is only one function long.
[SinglePipe 10/25] Use a function call when a pipeline is only one function long.
File: test/my_code_test.ex
[TestFileExt -/-] The file must be renamed to test/my_code_test.exs so that ExUnit can find it.
Finished in 0.05 seconds.
```
With the switch `--autocorrect` (alias `-a`), correctors that are configured
with `autocorrect: false` going into the corrections mode.
Use the switch `--task` (alias `-t`) to run a specific task. This switch can be
used multiple times.
The last two switches are helpful for the task `IOInspect` and `Dbg`. Both of
the tasks are correctors configured with `autocorrect: false` in the default
configuration. The following example shows how to run these two tasks.
```
> cd examples/my_code
> mix recode -t IOInspect -t Dbg
Found 18 files, including 3 scripts.
....................................
File: lib/my_code/multi.ex
[Dbg 9/32] There should be no calls to dbg.
[IOInspect 24/8] There should be no calls to IO.inspect.
Finished in 0.04 seconds.
```
To delete all occurrences of `dbg` and `IO.inspect` the following call can be
used.
```
> cd examples/my_code
> mix recode -av -t IOInspect -t Dbg
Found 18 files, including 3 scripts.
....................................
File: lib/my_code/multi.ex
Updates: 2
Changed by: Dbg, IOInspect
...|
7 7 |
8 8 | def pipe(x) do
9 - | x |> double |> double() |> dbg()
9 + | x |> double |> double()
10 10 | end
11 11 |
...|
22 22 | |> Enum.filter(fn x -> rem(x, 2) == 0 end)
23 23 | |> Enum.count()
24 - | |> IO.inspect()
25 24 | end
26 25 |end
...|
Finished in 0.04 seconds.
```
The `-av` stands for the switches `--autocorrect` and `--verbose`. The switch
`--verbose` causes `recode` to display all changes as a diff on the console.
### `mix format`
You can also run Recode together with `mix format` by adding
`Recode.FormatterPlugin` to your `.formatter.exs` plugins:
```elixir
[
inputs: ["{mix,.formatter}.exs", "{config,lib,test}/**/*.{ex,exs}"],
plugins: [Recode.FormatterPlugin]
]
```
### `mix recode.help`
The task `recode.help` prints all available recode-task with a short description.
The task prints the documentation for a given recode-task.
```sh
> mix recode.help Dbg
Recode.Task.Dbg
Calls to dbg/2 should only appear in debug sessions.
This task rewrites the code when mix recode runs with autocorrect: true.
```
## Differences to Credo
`recode` was started as a plugin for `credo`. Unfortunately it was not possible
to implement autocorrection as a plugin because Credo's traversal of the code does
not support changing the code.
Maybe some code lines from `recode` could be used as inspiration for `credo`
to bring the autocorrect feature to `credo`.
Other differences:
* `recode` requires Elixir 1.13, `credo` requires Elixir 1.7
* `recode` has autocorrection
* `credo` has much more checkers
* `credo` is faster
* `credo` has more features
