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doc_ast.ex
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doc_ast.ex
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defmodule ExDoc.DocAST do
@moduledoc false
@type t :: term()
alias ExDoc.Markdown
@doc """
Parses given `doc_content` according to `doc_format`.
"""
def parse!(doc_content, doc_format, options \\ [])
def parse!(markdown, "text/markdown", opts) do
parse_markdown(markdown, opts)
end
def parse!(ast, "application/erlang+html", _options) do
parse_erl_ast(ast)
end
def parse!(_ast, other, _opts) do
raise "content type #{inspect(other)} is not supported"
end
# https://www.w3.org/TR/2011/WD-html-markup-20110113/syntax.html#void-element
@void_elements ~W(area base br col command embed hr img input keygen link
meta param source track wbr)a
@doc """
Transform AST into string.
"""
def to_string(ast, fun \\ fn _ast, string -> string end)
def to_string(binary, _fun) when is_binary(binary) do
ExDoc.Utils.h(binary)
end
def to_string(list, fun) when is_list(list) do
result = Enum.map_join(list, "", &to_string(&1, fun))
fun.(list, result)
end
def to_string({:comment, _attrs, inner, _meta} = ast, fun) do
fun.(ast, "<!--#{inner}-->")
end
def to_string({tag, attrs, _inner, _meta} = ast, fun) when tag in @void_elements do
result = "<#{tag}#{ast_attributes_to_string(attrs)}/>"
fun.(ast, result)
end
def to_string({tag, attrs, inner, %{verbatim: true}} = ast, fun) do
inner = Enum.join(inner, "")
result = "<#{tag}#{ast_attributes_to_string(attrs)}>" <> inner <> "</#{tag}>"
fun.(ast, result)
end
def to_string({tag, attrs, inner, _meta} = ast, fun) do
result = "<#{tag}#{ast_attributes_to_string(attrs)}>" <> to_string(inner, fun) <> "</#{tag}>"
fun.(ast, result)
end
defp ast_attributes_to_string(attrs) do
Enum.map(attrs, fn {key, val} -> " #{key}=\"#{val}\"" end)
end
## parse markdown
defp parse_markdown(markdown, opts) do
Markdown.to_ast(markdown, opts)
end
## parse erlang+html
defp parse_erl_ast(binary) when is_binary(binary) do
binary
end
defp parse_erl_ast(list) when is_list(list) do
Enum.map(list, &parse_erl_ast/1)
end
defp parse_erl_ast({:pre, attrs, content}) do
case content do
# if we already have <pre><code>...</code></pre>, carry on
[{:code, _, _}] ->
{:pre, attrs, parse_erl_ast(content), %{}}
# otherwise, turn <pre>...</pre> into <pre><code>...</code></pre>
_ ->
content = [{:code, [], parse_erl_ast(content), %{}}]
{:pre, attrs, content, %{}}
end
end
defp parse_erl_ast({tag, attrs, content}) when is_atom(tag) do
{tag, attrs, parse_erl_ast(content), %{}}
end
@doc """
Extracts leading title element from the given AST.
If found, the title element is stripped from the resulting AST.
"""
def extract_title(ast)
def extract_title([{:comment, _, _, _} | ast]), do: extract_title(ast)
def extract_title([{:h1, _attrs, inner, _meta} | ast]), do: {:ok, inner, ast}
def extract_title(_ast), do: :error
@doc """
Returns text content from the given AST.
"""
def text_from_ast(ast) do
ast
|> do_text_from_ast()
|> IO.iodata_to_binary()
|> String.trim()
end
def do_text_from_ast(ast) when is_list(ast) do
Enum.map(ast, &do_text_from_ast/1)
end
def do_text_from_ast(ast) when is_binary(ast), do: ast
def do_text_from_ast({_tag, _attr, ast, _meta}), do: text_from_ast(ast)
@doc """
Wraps a list of HTML nodes into `<section>` tags whenever `matcher` returns true.
"""
def sectionize(list, matcher), do: sectionize(list, matcher, [])
defp sectionize(list, matcher, acc) do
case pivot(list, acc, matcher) do
{acc, {header_tag, header_attrs, _, _} = header, rest} ->
{inner, rest} = Enum.split_while(rest, ¬_tag?(&1, header_tag))
class = String.trim_trailing("#{header_tag} #{header_attrs[:class]}")
section = {:section, [class: class], [header | sectionize(inner, matcher, [])], %{}}
sectionize(rest, matcher, [section | acc])
acc ->
acc
end
end
defp not_tag?({tag, _, _, _}, tag), do: false
defp not_tag?(_, _tag), do: true
defp pivot([head | tail], acc, fun) do
case fun.(head) do
true -> {acc, head, tail}
false -> pivot(tail, [head | acc], fun)
end
end
defp pivot([], acc, _fun), do: Enum.reverse(acc)
@doc """
Highlights a DocAST converted to string.
"""
def highlight(html, language, opts \\ []) do
highlight_info = language.highlight_info()
Regex.replace(
~r/<pre(\s+class="\w*")?><code(?:\s+class="(\w*)")?>([^<]*)<\/code><\/pre>/,
html,
&highlight_code_block(&1, &2, &3, &4, highlight_info, opts)
)
end
defp highlight_code_block(full_block, pre_attr, lang, code, highlight_info, outer_opts) do
case pick_language_and_lexer(lang, highlight_info, code) do
{_language, nil, _opts} -> full_block
{lang, lexer, opts} -> render_code(pre_attr, lang, lexer, opts, code, outer_opts)
end
end
defp pick_language_and_lexer("", _highlight_info, "$ " <> _) do
{"shell", ExDoc.ShellLexer, []}
end
defp pick_language_and_lexer("output", highlight_info, _code) do
{"output", highlight_info.lexer, highlight_info.opts}
end
defp pick_language_and_lexer("", highlight_info, _code) do
{highlight_info.language_name, highlight_info.lexer, highlight_info.opts}
end
defp pick_language_and_lexer(lang, _highlight_info, _code) do
case Makeup.Registry.fetch_lexer_by_name(lang) do
{:ok, {lexer, opts}} -> {lang, lexer, opts}
:error -> {lang, nil, []}
end
end
defp render_code(pre_attr, lang, lexer, lexer_opts, code, opts) do
highlight_tag = Keyword.get(opts, :highlight_tag, "span")
highlighted =
code
|> unescape_html()
|> IO.iodata_to_binary()
|> Makeup.highlight_inner_html(
lexer: lexer,
lexer_options: lexer_opts,
formatter_options: [highlight_tag: highlight_tag]
)
~s(<pre#{pre_attr}><code class="makeup #{lang}" translate="no">#{highlighted}</code></pre>)
end
entities = [{"&", ?&}, {"<", ?<}, {">", ?>}, {""", ?"}, {"'", ?'}]
for {encoded, decoded} <- entities do
defp unescape_html(unquote(encoded) <> rest) do
[unquote(decoded) | unescape_html(rest)]
end
end
defp unescape_html(<<c, rest::binary>>) do
[c | unescape_html(rest)]
end
defp unescape_html(<<>>) do
[]
end
end