92 lines
2.3 KiB
Elixir
92 lines
2.3 KiB
Elixir
defmodule Lain.Markdown do
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@default_opts [
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pure_links: true,
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wikilinks: true,
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inner_html: false,
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escape: false,
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math: true,
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smartypants: true
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]
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def render(source, opts \\ []) do
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opts = Keyword.merge(@default_opts, opts, fn _key, _default_value, value -> value end)
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inner_html = Keyword.get(opts, :inner_html, false)
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EarmarkParser.as_ast(source || "", opts)
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|> case do
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{:ok, ast, _} ->
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ast
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|> Earmark.Transform.map_ast(&transformer/1)
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|> walk()
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|> Enum.map(&maybe_remove_para(&1, inner_html))
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other ->
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other
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end
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|> Earmark.Transform.transform(%{
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initial_indent: 0,
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indent: 2,
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compact_output: false,
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escape: false
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})
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end
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defp transformer({"a", attrs, ignored, meta}) do
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href = Enum.find_value(attrs, "", fn {key, value} -> key == "href" && value end)
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href_uri = URI.parse(href)
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is_internal = href_uri.host in [host(), nil]
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attrs =
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if is_internal do
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attrs
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else
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[{"target", "_blank"} | attrs]
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end
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{"a", attrs, ignored, meta}
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end
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defp transformer(other), do: other
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def walk(list) when is_list(list), do: Enum.map(list, &walk/1)
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def walk(binary) when is_binary(binary), do: binary
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def walk({"pre", _attrs, [{"code", attrs, [children], _}], _meta}) do
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lang = Earmark.AstTools.find_att_in_node(attrs, "class")
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walk(highlight(children, lang))
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end
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def walk({tag, attrs, children, meta}), do: {tag, attrs, walk(children), meta}
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defp maybe_remove_para(node, false), do: node
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defp maybe_remove_para({"p", _attrs, children, _meta}, true),
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do: Enum.map(children, &add_trailing_newline/1)
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defp maybe_remove_para(other, true), do: other
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defp highlight([text], lang), do: highlight(text, lang)
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defp highlight(text, lang) do
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highlight = Autumn.highlight!(text, language: lang || "plain")
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{"div", [], [highlight], %{verbatim: true}}
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end
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def floki2earmark(list) when is_list(list) do
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Enum.map(list, &floki2earmark/1)
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end
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def floki2earmark(text) when is_binary(text), do: text
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def floki2earmark({tag, attrs, children}), do: {tag, attrs, floki2earmark(children), %{}}
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defp add_trailing_newline(string) when is_binary(string), do: "#{string}\n"
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defp add_trailing_newline(other), do: other
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defp host(), do: Application.get_env(:lain, :host)
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end
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