View Source Inspect.Opts (Elixir v1.18.0)

Defines the options used by the Inspect protocol.

The following fields are available:

  • :base - prints integers and binaries as :binary, :octal, :decimal, or :hex. Defaults to :decimal.

  • :binaries - when :as_binaries all binaries will be printed in bit syntax.

    When :as_strings all binaries will be printed as strings, non-printable bytes will be escaped.

    When the default :infer, the binary will be printed as a string if :base is :decimal and if it is printable, otherwise in bit syntax. See String.printable?/1 to learn when a string is printable.

  • :charlists - when :as_charlists all lists will be printed as charlists, non-printable elements will be escaped.

    When :as_lists all lists will be printed as lists.

    When the default :infer, the list will be printed as a charlist if it is printable, otherwise as list. See List.ascii_printable?/1 to learn when a charlist is printable.

  • :custom_options (since v1.9.0) - a keyword list storing custom user-defined options. Useful when implementing the Inspect protocol for nested structs to pass the custom options through.

    It supports some pre-defined keys:

    • :sort_maps (since v1.14.4) - if set to true, sorts key-value pairs in maps. This can be helpful to make map inspection deterministic for testing, given maps key order is random.

  • :inspect_fun (since v1.9.0) - a function to build algebra documents. Defaults to Inspect.Opts.default_inspect_fun/0.

  • :limit - limits the number of items that are inspected for tuples, bitstrings, maps, lists and any other collection of items, with the exception of printable strings and printable charlists which use the :printable_limit option. If you don't want to limit the number of items to a particular number, use :infinity. It accepts a positive integer or :infinity. Defaults to 50.

  • :pretty - if set to true enables pretty printing. Defaults to false.

  • :printable_limit - limits the number of characters that are inspected on printable strings and printable charlists. You can use String.printable?/1 and List.ascii_printable?/1 to check if a given string or charlist is printable. If you don't want to limit the number of characters to a particular number, use :infinity. It accepts a positive integer or :infinity. Defaults to 4096.

  • :safe - when false, failures while inspecting structs will be raised as errors instead of being wrapped in the Inspect.Error exception. This is useful when debugging failures and crashes for custom inspect implementations. Defaults to true.

  • :structs - when false, structs are not formatted by the inspect protocol, they are instead printed as maps. Defaults to true.

  • :syntax_colors - when set to a keyword list of colors the output is colorized. The keys are types and the values are the colors to use for each type (for example, [number: :red, atom: :blue]). Types can include :atom, :binary, :boolean, :list, :map, :number, :regex, :string, :tuple, or some types to represent AST like :variable, :call, and :operator. Custom data types may provide their own options. Colors can be any IO.ANSI.ansidata/0 as accepted by IO.ANSI.format/1. A default list of colors can be retrieved from IO.ANSI.syntax_colors/0.

  • :width - number of characters per line used when pretty is true or when printing to IO devices. Set to 0 to force each item to be printed on its own line. If you don't want to limit the number of items to a particular number, use :infinity. Defaults to 80.

Summary

Types

color_key()
t()

Functions

default_inspect_fun()

Returns the default inspect function.

default_inspect_fun(fun)

Sets the default inspect function.

new(opts)

Builds an Inspect.Opts struct.

Types

color_key()

@type color_key() :: atom()

t()

@type t() :: %Inspect.Opts{
  base: :decimal | :binary | :hex | :octal,
  binaries: :infer | :as_binaries | :as_strings,
  char_lists: term(),
  charlists: :infer | :as_lists | :as_charlists,
  custom_options: keyword(),
  inspect_fun: (any(), t() -> Inspect.Algebra.t()),
  limit: non_neg_integer() | :infinity,
  pretty: boolean(),
  printable_limit: non_neg_integer() | :infinity,
  safe: boolean(),
  structs: boolean(),
  syntax_colors: [{color_key(), IO.ANSI.ansidata()}],
  width: non_neg_integer() | :infinity
}

Functions

default_inspect_fun()

(since 1.13.0) 
@spec default_inspect_fun() :: (term(), t() -> Inspect.Algebra.t())

Returns the default inspect function.

default_inspect_fun(fun)

(since 1.13.0) 
@spec default_inspect_fun((term(), t() -> Inspect.Algebra.t())) :: :ok

Sets the default inspect function.

Set this option with care as it will change how all values in the system are inspected. The main use of this functionality is to provide an entry point to filter inspected values, in order for entities to comply with rules and legislations on data security and data privacy.

It is extremely discouraged for libraries to set their own function as this must be controlled by applications. Libraries should instead define their own structs with custom inspect implementations. If a library must change the default inspect function, then it is best to ask users of your library to explicitly call default_inspect_fun/1 with your function of choice.

The default is Inspect.inspect/2.

Examples 

previous_fun = Inspect.Opts.default_inspect_fun()

Inspect.Opts.default_inspect_fun(fn
  %{address: _} = map, opts ->
    previous_fun.(%{map | address: "[REDACTED]"}, opts)

  value, opts ->
    previous_fun.(value, opts)
end)

new(opts)

(since 1.13.0) 
@spec new(keyword()) :: t()

Builds an Inspect.Opts struct.