Presentation

Clouseau is a silly little inspector. Essentialy is an enhancement over the IO.inspect function. It adds the functionality to display the file, module and line number of the calling location. Also it can optionaly display a line under the inspected term to separate it from other output on the screen.

How to install

Add clouseau to your list of dependencies in mix.exs

def deps do
  [
    #...
    {:clouseau, "~> 0.3.0"}
  ]
end

How to use

In order to use Clauseau you first must require the Cl module

    require Cl

Clouseau exports two macros: Cl.inspect/2 and Cl.inspect/3. Just use them instead of IO.inspect.

    Cl.inspect("test", label: "This is a test")

Switches

Both macros are ready to use out of the box. By default they display the file, module and line where the macro was called, above the label and the inspected term.

clouseau uses OptionParser to parse the switches. The switches can be given directly in the label option. You can use switches to modify what will be shown.

Cl.inspect({"test", 7, %{banana: :yellow}}, label: "--no-file Test showing only module and line")
# Clouseau.ClTest:20
# Test showing only module and line: {"test", 7, %{banana: :yellow}}

Cl.inspect({"test", 7}, label: "-b Test With border", syntax_colors: [number: :blue])
# lib/cltest.ex
# Clouseau.ClTest:26
# Test With border: {"test", 7}
# -------------------------------------------------------------------------------------
# {"test", 7}

Switches that are intended to be used must be grouped in the beginning of the string. Any non-switch group of characters stops the parser and the rest of the line is treated as the text of the label. For example:

Cl.inspect({"test", 7, [banana: "split"]}, label: "--no-module --no-line -b Showing only the --file option. The --no-border option has no effect")
# lib/cltest.ex
# Showing only the --file option. The --no-border option has no effect: {"test", 7, [banana: "split"]}
# --------------------------------------------------------------------------------------------------------------------------------------------------

Note: The first space on the label text is always discarded. The rest of the spaces stay there. This is intentional to keep it as consistent as possible with IO.inspect who does not trim white spaces. For example:

 Cl.inspect({"test", 7}, label: "-b      Test With border", syntax_colors: [number: :blue])
 #lib/cltest.ex
 #Clouseau.ClTest:26
 #     Test With border: {"test", 7}
 #------------------------------------------------------------------------------------------

The distance between the switch and the text is 6 spaces while the result displays 5 spaces. If, for some reason, you depend on IO.inspect not triming the white space, keep this behavior in mind.

The available switches are:

switch | type | default | shortcut | description ----------|----------|---------|----------|---------------------- file: | :boolean | true | f | Display the file where this call happened full_path | :boolean | false | none | Display the file as absolute path or relative to project root. Default is relative to project root module: | :boolean | true | m | Display the module where this call happened line: | :boolean | true | l | Display the line where this call happened text: | :boolean | true | t | Display the descriptive text for the label border: | :boolean | false | b | Display a border under the inspected term

If you wish to have your default set of switches you can set options in your config

   config :clouseau,
      default_switches: [module: true, line: true, file: true, border: true]

Template

clouseau uses an EEx template to display the various parts of the label. The template uses a custom engine instead of the default EEx.SmartEngine. The differences are:

It doesn't add a line break on tag's end. Instead you shoud add a "\n"where you want a line break. The reason for this change is beacuse this way the line break can be controlled with conditionals.
It supports a has_val?/1 function that returns true if the value is not one of nil, false or "".
The @ function desn't use Access.fetch/2 but Map.get/2 to get the value. It does not warn or rise any errors. Instead it returns an empty string.

The format of the label is not configurable on the fly. If, for example, it is prefered to display the module before the line, this can be changed only by using a diferent template at compile time.

You can use a custom template by setting in your config. Below it is shown the default template as an example.

  config :clouseau,
    template: """
              <% import IO.ANSI %>
              <%= if has_val?(file), do: blue() <> @file <> "\n" %>
              <%= green() <> @module %><%=  if has_val?(module), do: ":" %>
              <%= red() <> @line %>
              <%= if has_val?(module) || has_val?(line), do: "\n" %>
              <%= yellow()  <> @text <> reset() %><%= if has_val?(text), do: ": " %>
              <%= reset()  %>
              """

Credo

clouseau provides two custom credo checks: Clouseau.Check.Warning.ClInspect and Clouseau.Check.Warning.RequireCl. To use them just append them to the :checks option in your .credo.exs file.

      checks: [

        # ... some checks

        # Custom checks can be created using `mix credo.gen.check`.
        #

        {Clouseau.Check.Warning.ClInspect},
        {Clouseau.Check.Warning.RequireCl},
      ]

TODO

Add some tests
Add dialyzer documentation