Improve down parsing

Author: RoyalIcing

apps/components_guide_web/lib/components_guide_web/views/down_view.ex

@@ -2,7 +2,7 @@ defmodule ComponentsGuideWeb.DownView do
   use ComponentsGuideWeb, :view
 
   defmodule ParserState do
-    defstruct bold: false, italics: false, html: []
+    defstruct html: [], italics: nil, bold: nil, link: nil
 
     @spec parse(binary) ::
             {:safe,
@@ -15,33 +15,93 @@ defmodule ComponentsGuideWeb.DownView do
       next(%__MODULE__{}, input)
     end
 
-    defp next(state = %__MODULE__{italics: true}, <<"_"::utf8>> <> rest) do
-      %__MODULE__{state | html: [state.html], italics: false}
+    # Links
+
+    defp next(state = %__MODULE__{link: nil}, <<"["::utf8>> <> rest) do
+      %__MODULE__{state | link: {:capturing_text, []}}
       |> next(rest)
     end
 
-    defp next(state = %__MODULE__{italics: false}, <<"_"::utf8>> <> rest) do
-      %__MODULE__{state | html: ["<em1>" | state.html], italics: true}
+    defp next(state = %__MODULE__{link: {:capturing_text, text_chars}}, <<"]"::utf8>> <> rest) do
+      %__MODULE__{state | link: {:ready_for_url, text_chars}}
       |> next(rest)
     end
 
-    defp next(state = %__MODULE__{}, <<char::utf8>> <> rest) do
-      %__MODULE__{state | html: [<<char::utf8>> | state.html]}
+    defp next(
+           state = %__MODULE__{link: {:capturing_text, text_chars}},
+           <<char::utf8>> <> rest
+         ) do
+      %__MODULE__{state | link: {:capturing_text, [char | text_chars]}}
+      |> next(rest)
+    end
+
+    defp next(state = %__MODULE__{link: {:ready_for_url, text_chars}}, <<"("::utf8>> <> rest) do
+      %__MODULE__{state | link: {:capturing_url, text_chars, []}}
+      |> next(rest)
+    end
+
+    defp next(
+           state = %__MODULE__{link: {:capturing_url, text_chars, url_chars}},
+           <<")"::utf8>> <> rest
+         ) do
+      text = text_chars |> Enum.reverse() |> List.to_string()
+      url = url_chars |> Enum.reverse() |> List.to_string()
+
+      anchor_html = Phoenix.HTML.Link.link(text, to: url) |> Phoenix.HTML.safe_to_string()
+
+      %__MODULE__{state | html: [anchor_html | state.html], link: nil}
+      |> next(rest)
+    end
+
+    defp next(
+           state = %__MODULE__{link: {:capturing_url, link_chars, url_chars}},
+           <<char::utf8>> <> rest
+         ) do
+      %__MODULE__{state | link: {:capturing_url, link_chars, [char | url_chars]}}
+      |> next(rest)
+    end
+
+    # Bold
+
+    defp next(state = %__MODULE__{bold: nil}, <<"**"::utf8>> <> rest) do
+      %__MODULE__{state | html: ["<strong>" | state.html], bold: "**"}
       |> next(rest)
     end
 
-    defp next(state = %__MODULE__{italics: italics}, "") do
-      html = Enum.reverse(state.html) |> Enum.join()
+    defp next(state = %__MODULE__{bold: "**"}, <<"**"::utf8>> <> rest) do
+      %__MODULE__{state | html: ["</strong>" | state.html], bold: nil}
+      |> next(rest)
+    end
+
+    # Italics
+
+    defp next(state = %__MODULE__{italics: nil}, <<"_"::utf8>> <> rest) do
+      %__MODULE__{state | html: ["<em>" | state.html], italics: "_"}
+      |> next(rest)
+    end
+
+    defp next(state = %__MODULE__{italics: "_"}, <<"_"::utf8>> <> rest) do
+      %__MODULE__{state | html: ["</em>" | state.html], italics: nil}
+      |> next(rest)
+    end
 
-      html =
-        case italics do
-          true ->
-            html <> "</em>"
+    defp next(state = %__MODULE__{italics: nil}, <<"*"::utf8>> <> rest) do
+      %__MODULE__{state | html: ["<em>" | state.html], italics: "*"}
+      |> next(rest)
+    end
+
+    defp next(state = %__MODULE__{italics: "*"}, <<"*"::utf8>> <> rest) do
+      %__MODULE__{state | html: ["</em>" | state.html], italics: nil}
+      |> next(rest)
+    end
 
-          false ->
-            html
-        end
+    defp next(state = %__MODULE__{}, <<char::utf8>> <> rest) do
+      %__MODULE__{state | html: [<<char::utf8>> | state.html]}
+      |> next(rest)
+    end
 
+    defp next(state = %__MODULE__{}, "") do
+      html = state.html |> Enum.reverse() |> Enum.join()
       Phoenix.HTML.raw(html)
     end
   end

apps/components_guide_web/test/collected_live_web/views/down_view_test.exs

@@ -9,8 +9,21 @@ defmodule ComponentsGuideWeb.DownViewTest do
       assert Subject.down("plain text") == raw("plain text")
     end
 
-    test "italics" do
-      assert Subject.down("plain _text_") == raw("plain <em>text</em>")
+    test "italics with _" do
+      assert Subject.down("text _italics_ normal") == raw("text <em>italics</em> normal")
+    end
+
+    test "italics with *" do
+      assert Subject.down("text *italics* normal") == raw("text <em>italics</em> normal")
+    end
+
+    test "bold with **" do
+      assert Subject.down("text **bold** normal") == raw("text <strong>bold</strong> normal")
+    end
+
+    test "link with inline url" do
+      assert Subject.down("text with [link](https://example.org/) somewhere") ==
+               raw("text with <a href=\"https://example.org/\">link</a> somewhere")
     end
   end
 end