View Source Moar.Opts (Moar v1.52.1)

Extracts keys and values from enumerables, especially from function options.

There are three main functions, each of which takes an opts enumerable as input. get/3 extracts one value from the opts with an optional default value. pop/3 is like get/3 but removes the opt from opts and returns the opt and the remaining opts as a tuple. take/2 extracts multiple values from the opts with optional default values for some or all keys.

get/3, pop/3, and take/2 differ from their Map and Keyword counterparts in the following ways:

  • get/3, pop/3, and take/2 accept any enumerable, including maps, keyword lists, and mixed lists like [:a, :b, c: 3, d: 4].
  • get/3, pop/3, and take/2 will fall back to the default value if the given key's value is blank as defined by Moar.Term.blank?/1 (nil, empty strings, strings made up only of whitespace, empty lists, and empty maps), and will default valueless keys (e.g., :a in [:a, b: 2]) to true unless a different default is specified. The corresponding Map and Keyword functions only fall back to the default value if the value is exactly nil, and Keyword functions don't support valueless keys.
  • get/3, pop/3, and take/2 allow default values to be specified.
  • take/2 will return the value for a requested key even if the key is not in the input enumerable.

Example using get/2 and get/3:

def build_url(path, opts \\ []) do
  %URI{
    path: path,
    host: Moar.Opts.get(opts, :host, "localhost"),
    port: Moar.Opts.get(opts, :port),
    scheme: "https"
  } |> URI.to_string()
end

Examples using take/2:

# example using pattern matching
def build_url(path, opts \ []) do
  %{host: h, port: p} = Moar.Opts.take(opts, [:port, host: "localhost"])
  %URI{path: path, host: h, port: p, scheme: "https"} |> URI.to_string()
end

# example rebinding `opts` to the parsed opts
def build_url(path, opts \ []) do
  opts = Moar.Opts.take(opts, [:port, host: "localhost"])
  %URI{path: path, host: opts.host, port: opts.port, scheme: "https"} |> URI.to_string()
end

Summary

Functions

Deletes an opt given a key, a {key, value}, or a function that accepts opts and a map, list, or term.

Get the value of key from input, falling back to optional default if the key does not exist, or if its value is blank (via Moar.Term.blank?/1).

Removes an opt from the opts (via get/3), returning {opt, remaining_opts}.

Get the value each key in keys from input, falling back to optional default values for keys that do not exist, or for values that are blank (via Moar.Term.blank?/1).

Functions

@spec delete(map() | list(), any()) :: map() | list()

Deletes an opt given a key, a {key, value}, or a function that accepts opts and a map, list, or term.

iex> Moar.Opts.delete(%{a: 1, b: 2}, :a)
%{b: 2}

iex> Moar.Opts.delete([a: 1, b: 2], :a)
[b: 2]

iex> Moar.Opts.delete([:a, b: 2], :a)
[b: 2]

iex> Moar.Opts.delete([a: 1, b: 2], :a, 1)
[b: 2]

iex> Moar.Opts.delete([a: 1, b: 2], :a, 99)
[a: 1, b: 2]

iex> Moar.Opts.delete([:a, b: 2], :a, 1)
[:a, b: 2]

iex> Moar.Opts.delete([:trim, :downcase, :reverse], fn k -> k == :downcase end)
[:trim, :reverse]

iex> Moar.Opts.delete([a: 1, b: 2, c: 3, d: 4], fn {_k, v} -> Integer.mod(v, 2) == 0 end)
[a: 1, c: 3]
Link to this function

delete(input, key, value)

View Source
@spec delete(map() | list(), any(), any()) :: map() | list()
Link to this function

get(input, key, default \\ nil)

View Source
@spec get(Enum.t(), binary() | atom(), any()) :: any()

Get the value of key from input, falling back to optional default if the key does not exist, or if its value is blank (via Moar.Term.blank?/1).

iex> [a: 1, b: 2] |> Moar.Opts.get(:a)
1

iex> [:a, b: 2] |> Moar.Opts.get(:a)
true

iex> [a: 1, b: 2] |> Moar.Opts.get(:c)
nil

iex> [a: 1, b: 2, c: ""] |> Moar.Opts.get(:c)
nil

iex> [a: 1, b: 2, c: %{}] |> Moar.Opts.get(:c)
nil

iex> [a: 1, b: 2, c: "   "] |> Moar.Opts.get(:c, 300)
300
Link to this function

pop(input, key, default \\ nil)

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@spec pop(Enum.t(), binary() | atom(), any()) :: {any(), Enum.t()}

Removes an opt from the opts (via get/3), returning {opt, remaining_opts}.

iex> [a: 1, b: 2] |> Moar.Opts.pop(:a)
{1, [b: 2]}

iex> [:a, b: 2] |> Moar.Opts.pop(:a)
{true, [b: 2]}
Link to this function

replace(opts, key, replacement)

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@spec replace(map(), {any(), any()}, {any(), any()}) :: map()
@spec replace(list(), {any(), any()} | any(), any()) :: list()

Replace an opt.

iex> Moar.Opts.replace(%{a: 1, b: 2}, {:a, 1}, {:a, 100})
%{a: 100, b: 2}

iex> Moar.Opts.replace([a: 1, b: 2], {:a, 1}, {:a, 100})
[a: 100, b: 2]

iex> Moar.Opts.replace([:a, b: 2], :a, :aa)
[:aa, b: 2]
@spec take(Enum.t(), list()) :: map()

Get the value each key in keys from input, falling back to optional default values for keys that do not exist, or for values that are blank (via Moar.Term.blank?/1).

If key does not exist in keys, returns nil, or returns the default value if provided.

keys is a list of keys (e.g., [:a, :b]), a keyword list of keys and default values (e.g., [a: 1, b: 2]), or a hybrid list/keyword list (e.g., [:a, b: 2])

iex> [a: 1, b: 2] |> Moar.Opts.take([:a, :c])
%{a: 1, c: nil}

iex> [:a, b: 2] |> Moar.Opts.take([:a, :c])
%{a: true, c: nil}

iex> [a: 1, b: 2] |> Moar.Opts.take([:a, b: 0, c: 3])
%{a: 1, b: 2, c: 3}