popdoc: parse iex-popcorn blocks in markdown (3/5)

popdoc/lib/popdoc/markdown.ex

@@ -10,6 +10,12 @@ defmodule Popdoc.Markdown do
   @popcorn_code_class "elixir-popcorn"
   @eval_class "popcorn-eval"
 
+  @iex_code_class "iex-popcorn"
+  @iex_class "popcorn-iex"
+
+  @iex_prompt_re ~r/^iex(?:\(\d+\))?> ?/
+  @cont_prompt_re ~r/^\.\.\.(?:\(\d+\))?> ?/
+
   def available? do
     case earmark_adapter() do
       {:ok, module} -> apply(module, :available?, [])
@@ -26,12 +32,27 @@ defmodule Popdoc.Markdown do
   defp walk(list) when is_list(list), do: walk_list(list, [])
 
   defp walk({:pre, pre_attrs, [{:code, code_attrs, code_children, code_meta}], pre_meta}) do
-    if popcorn_code_block?(code_attrs) do
-      {:pre, add_class(pre_attrs, @eval_class),
-       [{:code, normalize_code_attrs(code_attrs), walk(code_children), code_meta}], pre_meta}
-    else
-      {:pre, pre_attrs, [{:code, code_attrs, walk(code_children), code_meta}], pre_meta}
-    end
+    {pre_attrs, code_attrs} =
+      cond do
+        popcorn_code_block?(code_attrs) ->
+          {add_class(pre_attrs, @eval_class), normalize_code_attrs(code_attrs)}
+
+        iex_code_block?(code_attrs) ->
+          commands_json =
+            code_children |> extract_text() |> parse_iex_commands() |> commands_to_json()
+
+          new_pre_attrs =
+            pre_attrs
+            |> add_class(@iex_class)
+            |> Keyword.put(:"data-popcorn-iex-commands", commands_json)
+
+          {new_pre_attrs, normalize_code_attrs(code_attrs)}
+
+        true ->
+          {pre_attrs, code_attrs}
+      end
+
+    {:pre, pre_attrs, [{:code, code_attrs, walk(code_children), code_meta}], pre_meta}
   end
 
   defp walk({tag, attrs, children, meta}), do: {tag, attrs, walk(children), meta}
@@ -46,12 +67,19 @@ defmodule Popdoc.Markdown do
     |> Enum.member?(@popcorn_code_class)
   end
 
+  defp iex_code_block?(attrs) do
+    attrs
+    |> class_tokens()
+    |> Enum.member?(@iex_code_class)
+  end
+
   defp normalize_code_attrs(attrs) do
     classes =
       attrs
       |> class_tokens()
       |> Enum.map(fn
         @popcorn_code_class -> "elixir"
+        @iex_code_class -> "elixir"
         class -> class
       end)
       |> Enum.uniq()
@@ -60,6 +88,54 @@ defmodule Popdoc.Markdown do
     Keyword.put(attrs, :class, classes)
   end
 
+  defp extract_text(children) when is_list(children) do
+    Enum.map_join(children, "", fn
+      text when is_binary(text) -> text
+      _ -> ""
+    end)
+  end
+
+  defp parse_iex_commands(text) do
+    {commands, current} =
+      text
+      |> String.split("\n")
+      |> Enum.reduce({[], nil}, fn line, {commands, current} ->
+        trimmed = String.trim_leading(line)
+
+        cond do
+          code = strip_prompt(trimmed, @iex_prompt_re) ->
+            acc = if current != nil, do: [current | commands], else: commands
+            {acc, code}
+
+          (cont = strip_prompt(trimmed, @cont_prompt_re)) && current != nil ->
+            {commands, current <> "\n" <> cont}
+
+          true ->
+            {commands, current}
+        end
+      end)
+
+    final = if current != nil, do: [current | commands], else: commands
+    Enum.reverse(final)
+  end
+
+  defp strip_prompt(line, prompt_re) do
+    case Regex.run(prompt_re, line) do
+      [prompt] -> String.replace_prefix(line, prompt, "")
+      nil -> nil
+    end
+  end
+
+  # ExDoc.Utils.to_json escapes every control character; a raw byte < 0x20
+  # in a doc line would otherwise make JSON.parse throw and silently disable
+  # the block. ExDoc is guaranteed loaded here: to_ast/2 already requires its
+  # Earmark adapter.
+  defp commands_to_json(commands) do
+    Module.concat([ExDoc, Utils])
+    |> apply(:to_json, [commands])
+    |> IO.iodata_to_binary()
+  end
+
   defp class_tokens(attrs) do
     attrs
     |> Keyword.get(:class, "")

popdoc/mix.lock

@@ -1,8 +1,8 @@
 %{
   "atomvm_packbeam": {:hex, :atomvm_packbeam, "0.8.2", "f981c2874df98187ee5685e5fd65e0fdc2848b35d418dce5eb0dac0a78a7574b", [:rebar3], [], "hexpm", "e60a55e2184698ec485fb1d02166b4cd173bbce5c99c7bced49a6e9be5f948ad"},
-  "earmark_parser": {:hex, :earmark_parser, "1.4.44", "f20830dd6b5c77afe2b063777ddbbff09f9759396500cdbe7523efd58d7a339c", [:mix], [], "hexpm", "4778ac752b4701a5599215f7030989c989ffdc4f6df457c5f36938cc2d2a2750"},
-  "ex_doc": {:hex, :ex_doc, "0.40.2", "f50edec428c4b0a457a167de42414c461122a3585a99515a69d09fff19e5597e", [:mix], [{:earmark_parser, "~> 1.4.44", [hex: :earmark_parser, repo: "hexpm", optional: false]}, {:makeup_c, ">= 0.1.0", [hex: :makeup_c, repo: "hexpm", optional: true]}, {:makeup_elixir, "~> 0.14 or ~> 1.0", [hex: :makeup_elixir, repo: "hexpm", optional: false]}, {:makeup_erlang, "~> 0.1 or ~> 1.0", [hex: :makeup_erlang, repo: "hexpm", optional: false]}, {:makeup_html, ">= 0.1.0", [hex: :makeup_html, repo: "hexpm", optional: true]}], "hexpm", "4fa426e2beb47854a162e2c488727fdec51cd4692e319b23810c2804cb1a40fe"},
-  "makeup": {:hex, :makeup, "1.2.1", "e90ac1c65589ef354378def3ba19d401e739ee7ee06fb47f94c687016e3713d1", [:mix], [{:nimble_parsec, "~> 1.4", [hex: :nimble_parsec, repo: "hexpm", optional: false]}], "hexpm", "d36484867b0bae0fea568d10131197a4c2e47056a6fbe84922bf6ba71c8d17ce"},
+  "earmark_parser": {:hex, :earmark_parser, "1.4.45", "cba8369ab2a1342e419bc2760eec731b17be828941dcf494045d44766227e1d5", [:mix], [], "hexpm", "d3ec045bf122965db20c0bdb420e19ee1415843135327124918473feb4b328e8"},
+  "ex_doc": {:hex, :ex_doc, "0.40.3", "4a972ffe64bc07dc605af487e98fc19b72a4185f55ca031b94c0552d6071c1d9", [:mix], [{:earmark_parser, "~> 1.4.44", [hex: :earmark_parser, repo: "hexpm", optional: false]}, {:makeup_c, ">= 0.1.0", [hex: :makeup_c, repo: "hexpm", optional: true]}, {:makeup_elixir, "~> 0.14 or ~> 1.0", [hex: :makeup_elixir, repo: "hexpm", optional: false]}, {:makeup_erlang, "~> 0.1 or ~> 1.0", [hex: :makeup_erlang, repo: "hexpm", optional: false]}, {:makeup_html, ">= 0.1.0", [hex: :makeup_html, repo: "hexpm", optional: true]}], "hexpm", "2756e357742fecd9749b489b85d67c9ce99c465f2e75728d9e6dc8d704b973de"},
+  "makeup": {:hex, :makeup, "1.2.2", "882d46dc0905e9ff7abf2aab61a7e6b3dcc555533977d8a23b06019e6c89ac94", [:mix], [{:nimble_parsec, "~> 1.4", [hex: :nimble_parsec, repo: "hexpm", optional: false]}], "hexpm", "9a1a24e5b343b8ae16abea0822c10a6f75da27af7fa802ada5251f7579bfccfa"},
   "makeup_elixir": {:hex, :makeup_elixir, "1.0.1", "e928a4f984e795e41e3abd27bfc09f51db16ab8ba1aebdba2b3a575437efafc2", [:mix], [{:makeup, "~> 1.0", [hex: :makeup, repo: "hexpm", optional: false]}, {:nimble_parsec, "~> 1.2.3 or ~> 1.3", [hex: :nimble_parsec, repo: "hexpm", optional: false]}], "hexpm", "7284900d412a3e5cfd97fdaed4f5ed389b8f2b4cb49efc0eb3bd10e2febf9507"},
   "makeup_erlang": {:hex, :makeup_erlang, "1.1.0", "835f7e60792e08824cda445639555d7bf1bbbddb1b60b306e33cb6f6db24dc74", [:mix], [{:makeup, "~> 1.0", [hex: :makeup, repo: "hexpm", optional: false]}], "hexpm", "1cd6780fb1dd1a03979abaed0fe82712b0625118fd5257d3ebbf73f960c73c3c"},
   "nimble_parsec": {:hex, :nimble_parsec, "1.4.2", "8efba0122db06df95bfaa78f791344a89352ba04baedd3849593bfce4d0dc1c6", [:mix], [], "hexpm", "4b21398942dda052b403bbe1da991ccd03a053668d147d53fb8c4e0efe09c973"},

popdoc/test/popdoc/markdown_test.exs

@@ -24,6 +24,84 @@ defmodule Popdoc.MarkdownTest do
       assert code_classes(pre) == ["elixir"]
     end
 
+    test "adds the iex class to code blocks marked by iex-popcorn" do
+      ast =
+        """
+        ```iex-popcorn
+        iex> x = 1 + 1
+        2
+        iex> x * 10
+        20
+        ```
+        """
+        |> Markdown.to_ast([])
+
+      assert [pre] = ast
+      assert pre_classes(pre) == ["popcorn-iex"]
+      assert code_classes(pre) == ["elixir"]
+    end
+
+    test "extracts ordered iex commands into data-popcorn-iex-commands" do
+      ast =
+        """
+        ```iex-popcorn
+        iex> x = 1 + 1
+        2
+        iex> x * 10
+        20
+        ```
+        """
+        |> Markdown.to_ast([])
+
+      assert [pre] = ast
+      assert data_attr(pre, :"data-popcorn-iex-commands") == ~s(["x = 1 + 1","x * 10"])
+    end
+
+    test "joins continuation lines into a single command" do
+      ast =
+        """
+        ```iex-popcorn
+        iex> x =
+        ...>   1 + 2
+        3
+        ```
+        """
+        |> Markdown.to_ast([])
+
+      assert [pre] = ast
+      assert data_attr(pre, :"data-popcorn-iex-commands") == "[\"x =\\n  1 + 2\"]"
+    end
+
+    test "recognizes numbered prompts and continuations" do
+      ast =
+        """
+        ```iex-popcorn
+        iex(1)> a = 1
+        iex(2)> b =
+        ...(2)>   2
+        ```
+        """
+        |> Markdown.to_ast([])
+
+      assert [pre] = ast
+      assert data_attr(pre, :"data-popcorn-iex-commands") == "[\"a = 1\",\"b =\\n  2\"]"
+    end
+
+    test "escapes control characters in commands" do
+      ast =
+        """
+        ```iex-popcorn
+        iex> IO.puts("a\fb")
+        ```
+        """
+        |> Markdown.to_ast([])
+
+      assert [pre] = ast
+      json = data_attr(pre, :"data-popcorn-iex-commands")
+      refute json =~ <<0x0C>>
+      assert json == "[\"IO.puts(\\\"a\\fb\\\")\"]"
+    end
+
     test "leaves HTML comments untouched" do
       ast =
         """
@@ -50,4 +128,8 @@ defmodule Popdoc.MarkdownTest do
     |> Keyword.get(:class, "")
     |> String.split()
   end
+
+  defp data_attr({:pre, attrs, _children, _meta}, key) do
+    Keyword.get(attrs, key)
+  end
 end