Specs

break(binary()) :: doc_break()

Returns a break document based on the given string.

This break can be rendered as a linebreak or as the given string, depending on the mode of the chosen layout.

Examples

Let's create a document by concatenating two strings with a break between them:

iex> doc = Inspect.Algebra.concat(["a", Inspect.Algebra.break("\t"), "b"])
iex> Inspect.Algebra.format(doc, 80)
["a", "\t", "b"]

Notice the break was represented with the given string, because we didn't reach a line limit. Once we do, it is replaced by a newline:

iex> break = Inspect.Algebra.break("\t")
iex> doc = Inspect.Algebra.concat([String.duplicate("a", 20), break, "b"])
iex> doc = Inspect.Algebra.group(doc)
iex> Inspect.Algebra.format(doc, 10)
["aaaaaaaaaaaaaaaaaaaa", "\n", "b"]

Specs

collapse_lines(pos_integer()) :: doc_collapse()

Collapse any new lines and whitespace following this node, emitting up to max new lines.

Specs

color(t(), Inspect.Opts.color_key(), Inspect.Opts.t()) :: doc_color()

Colors a document if the color_key has a color in the options.

Specs

concat([t()]) :: t()

Concatenates a list of documents returning a new document.

Examples

iex> doc = Inspect.Algebra.concat(["a", "b", "c"])
iex> Inspect.Algebra.format(doc, 80)
["a", "b", "c"]

Specs

concat(t(), t()) :: t()

Concatenates two document entities returning a new document.

Examples

iex> doc = Inspect.Algebra.concat("hello", "world")
iex> Inspect.Algebra.format(doc, 80)
["hello", "world"]

Specs

container_doc(
  t(),
  [any()],
  t(),
  Inspect.Opts.t(),
  (term(), Inspect.Opts.t() -> t()),
  keyword()
) :: t()

Wraps collection in left and right according to limit and contents.

It uses the given left and right documents as surrounding and the separator document separator to separate items in docs. If all entries in the collection are simple documents (texts or strings), then this function attempts to put as much as possible on the same line. If they are not simple, only one entry is shown per line if they do not fit.

The limit in the given inspect_opts is respected and when reached this function stops processing and outputs "..." instead.

Options

• :separator - the separator used between each doc
• :break - If :strict, always break between each element. If :flex, breaks only when necessary. If :maybe, chooses :flex only if all elements are text-based, otherwise is :strict

Examples

iex> inspect_opts = %Inspect.Opts{limit: :infinity}
iex> fun = fn i, _opts -> to_string(i) end
iex> doc = Inspect.Algebra.container_doc("[", Enum.to_list(1..5), "]", inspect_opts, fun)
iex> Inspect.Algebra.format(doc, 5) |> IO.iodata_to_binary()
"[1,\n 2,\n 3,\n 4,\n 5]"

iex> inspect_opts = %Inspect.Opts{limit: 3}
iex> fun = fn i, _opts -> to_string(i) end
iex> doc = Inspect.Algebra.container_doc("[", Enum.to_list(1..5), "]", inspect_opts, fun)
iex> Inspect.Algebra.format(doc, 20) |> IO.iodata_to_binary()
"[1, 2, 3, ...]"

iex> inspect_opts = %Inspect.Opts{limit: 3}
iex> fun = fn i, _opts -> to_string(i) end
iex> opts = [separator: "!"]
iex> doc = Inspect.Algebra.container_doc("[", Enum.to_list(1..5), "]", inspect_opts, fun, opts)
iex> Inspect.Algebra.format(doc, 20) |> IO.iodata_to_binary()
"[1! 2! 3! ...]"

Specs

empty() :: :doc_nil

Returns a document entity used to represent nothingness.

Examples

iex> Inspect.Algebra.empty()
:doc_nil

Specs

flex_break(binary()) :: doc_break()

Returns a flex break document based on the given string.

A flex break still causes a group to break, like break/1, but it is re-evaluated when the documented is rendered.

For example, take a group document represented as [1, 2, 3] where the space after every comma is a break. When the document above does not fit a single line, all breaks are enabled, causing the document to be rendered as:

[1,
 2,
 3]

However, if flex breaks are used, then each break is re-evaluated when rendered, so the document could be possible rendered as:

[1, 2,
 3]

Hence the name "flex". they are more flexible when it comes to the document fitting. On the other hand, they are more expensive since each break needs to be re-evaluated.

This function is used by container_doc/6 and friends to the maximum number of entries on the same line.

Specs

flex_glue(t(), binary(), t()) :: t()

Glues two documents (doc1 and doc2) inserting a flex_break/1 given by break_string between them.

This function is used by container_doc/6 and friends to the maximum number of entries on the same line.

Specs

fold_doc([t()], (t(), t() -> t())) :: t()

Folds a list of documents into a document using the given folder function.

The list of documents is folded "from the right"; in that, this function is similar to List.foldr/3, except that it doesn't expect an initial accumulator and uses the last element of docs as the initial accumulator.

Examples

iex> docs = ["A", "B", "C"]
iex> docs =
...>   Inspect.Algebra.fold_doc(docs, fn doc, acc ->
...>     Inspect.Algebra.concat([doc, "!", acc])
...>   end)
iex> Inspect.Algebra.format(docs, 80)
["A", "!", "B", "!", "C"]

Specs

force_unfit(t()) :: doc_force()

Forces the current group to be unfit.

Specs

format(t(), non_neg_integer() | :infinity) :: iodata()

Formats a given document for a given width.

Takes the maximum width and a document to print as its arguments and returns an IO data representation of the best layout for the document to fit in the given width.

The document starts flat (without breaks) until a group is found.

Examples

iex> doc = Inspect.Algebra.glue("hello", " ", "world")
iex> doc = Inspect.Algebra.group(doc)
iex> doc |> Inspect.Algebra.format(30) |> IO.iodata_to_binary()
"hello world"
iex> doc |> Inspect.Algebra.format(10) |> IO.iodata_to_binary()
"hello\nworld"

Specs

glue(t(), binary(), t()) :: t()

Glues two documents (doc1 and doc2) inserting the given break break_string between them.

For more information on how the break is inserted, see break/1.

Examples

iex> doc = Inspect.Algebra.glue("hello", "world")
iex> Inspect.Algebra.format(doc, 80)
["hello", " ", "world"]

iex> doc = Inspect.Algebra.glue("hello", "\t", "world")
iex> Inspect.Algebra.format(doc, 80)
["hello", "\t", "world"]

Specs

group(t(), :self | :inherit) :: doc_group()

Returns a group containing the specified document doc.

Documents in a group are attempted to be rendered together to the best of the renderer ability.

The group mode can also be set to :inherit, which means it automatically breaks if the parent group has broken too.

Examples

iex> doc =
...>   Inspect.Algebra.group(
...>     Inspect.Algebra.concat(
...>       Inspect.Algebra.group(
...>         Inspect.Algebra.concat(
...>           "Hello,",
...>           Inspect.Algebra.concat(
...>             Inspect.Algebra.break(),
...>             "A"
...>           )
...>         )
...>       ),
...>       Inspect.Algebra.concat(
...>         Inspect.Algebra.break(),
...>         "B"
...>       )
...>     )
...>   )
iex> Inspect.Algebra.format(doc, 80)
["Hello,", " ", "A", " ", "B"]
iex> Inspect.Algebra.format(doc, 6)
["Hello,", "\n", "A", "\n", "B"]

Specs

line() :: t()

A mandatory linebreak.

A group with linebreaks will fit if all lines in the group fit.

Examples

iex> doc =
...>   Inspect.Algebra.concat(
...>     Inspect.Algebra.concat(
...>       "Hughes",
...>       Inspect.Algebra.line()
...>     ),
...>     "Wadler"
...>   )
iex> Inspect.Algebra.format(doc, 80)
["Hughes", "\n", "Wadler"]

Specs

line(t(), t()) :: t()

Inserts a mandatory linebreak between two documents.

See line/0.

Examples

iex> doc = Inspect.Algebra.line("Hughes", "Wadler")
iex> Inspect.Algebra.format(doc, 80)
["Hughes", "\n", "Wadler"]

Specs

nest(t(), non_neg_integer() | :cursor | :reset, :always | :break) :: doc_nest()

Nests the given document at the given level.

If level is an integer, that's the indentation appended to line breaks whenever they occur. If the level is :cursor, the current position of the "cursor" in the document becomes the nesting. If the level is :reset, it is set back to 0.

mode can be :always, which means nesting always happen, or :break, which means nesting only happens inside a group that has been broken.

Examples

iex> doc = Inspect.Algebra.nest(Inspect.Algebra.glue("hello", "world"), 5)
iex> doc = Inspect.Algebra.group(doc)
iex> Inspect.Algebra.format(doc, 5)
["hello", "\n     ", "world"]

Specs

next_break_fits(t(), :enabled | :disabled) :: doc_fits()

Considers the next break as fit.

mode can be :enabled or :disabled. When :enabled, it will consider the document as fit as soon as it finds the next break, effectively cancelling the break. It will also ignore any force_unfit/1 in search of the next break.

When disabled, it behaves as usual and it will ignore any further next_break_fits/2 instruction.

Examples

This is used by Elixir's code formatter to avoid breaking code at some specific locations. For example, consider this code:

some_function_call(%{..., key: value, ...})

Now imagine that this code does not fit its line. The code formatter introduces breaks inside ( and ) and inside %{ and }. Therefore the document would break as:

some_function_call(
  %{
    ...,
    key: value,
    ...
  }
)

The formatter wraps the algebra document representing the map in next_break_fits/1 so the code is formatted as:

some_function_call(%{
  ...,
  key: value,
  ...
})

Specs

space(t(), t()) :: t()

Inserts a mandatory single space between two documents.

Examples

iex> doc = Inspect.Algebra.space("Hughes", "Wadler")
iex> Inspect.Algebra.format(doc, 5)
["Hughes", " ", "Wadler"]

Specs

string(String.t()) :: doc_string()

Creates a document represented by string.

While Inspect.Algebra accepts binaries as documents, those are counted by binary size. On the other hand, string documents are measured in terms of graphemes towards the document size.

Examples

The following document has 10 bytes and therefore it does not format to width 9 without breaks:

iex> doc = Inspect.Algebra.glue("olá", " ", "mundo")
iex> doc = Inspect.Algebra.group(doc)
iex> Inspect.Algebra.format(doc, 9)
["olá", "\n", "mundo"]

However, if we use string, then the string length is used, instead of byte size, correctly fitting:

iex> string = Inspect.Algebra.string("olá")
iex> doc = Inspect.Algebra.glue(string, " ", "mundo")
iex> doc = Inspect.Algebra.group(doc)
iex> Inspect.Algebra.format(doc, 9)
["olá", " ", "mundo"]

Specs

to_doc(any(), Inspect.Opts.t()) :: t()

Converts an Elixir term to an algebra document according to the Inspect protocol.