Simple Markdown rendering for skydoc

This uses apache velocity engine templates to create markdown-HTML. There are other alternatives, but there is already precedent for depending on this library from docgen.

RELNOTES: None.
PiperOrigin-RevId: 203795431

2 files changed, 81 insertions, 8 deletions

diff --git a/src/test/java/com/google/devtools/build/skydoc/testdata/multiple_files_test/golden.txt b/src/test/java/com/google/devtools/build/skydoc/testdata/multiple_files_test/golden.txt
index b1a4a66325..1b2d0a0b52 100644
--- a/src/test/java/com/google/devtools/build/skydoc/testdata/multiple_files_test/golden.txt
+++ b/src/test/java/com/google/devtools/build/skydoc/testdata/multiple_files_test/golden.txt
@@ -1,12 +1,83 @@
-my_rule
+<a name="#my_rule"></a>
+## my_rule
+
+<pre>
+my_rule(first, second)
+</pre>
+
 This is my rule. It does stuff.
-first,second
 
-other_rule
+### Attributes
+
+<table class="params-table">
+  <colgroup>
+    <col class="col-param" />
+    <col class="col-description" />
+  </colgroup>
+  <tbody>
+    <tr id="#my_rule_first">
+      <td><code>first</code></td>
+      <td>first my_rule doc string</td>
+    </tr>
+    <tr id="#my_rule_second">
+      <td><code>second</code></td>
+      <td></td>
+    </tr>
+  </tbody>
+</table>
+
+
+<a name="#other_rule"></a>
+## other_rule
+
+<pre>
+other_rule(fourth, third)
+</pre>
+
 This is another rule.
-third,fourth
 
-yet_another_rule
+### Attributes
+
+<table class="params-table">
+  <colgroup>
+    <col class="col-param" />
+    <col class="col-description" />
+  </colgroup>
+  <tbody>
+    <tr id="#other_rule_fourth">
+      <td><code>fourth</code></td>
+      <td></td>
+    </tr>
+    <tr id="#other_rule_third">
+      <td><code>third</code></td>
+      <td>third other_rule doc string</td>
+    </tr>
+  </tbody>
+</table>
+
+
+<a name="#yet_another_rule"></a>
+## yet_another_rule
+
+<pre>
+yet_another_rule(fifth)
+</pre>
+
 This is yet another rule
-fifth
+
+### Attributes
+
+<table class="params-table">
+  <colgroup>
+    <col class="col-param" />
+    <col class="col-description" />
+  </colgroup>
+  <tbody>
+    <tr id="#yet_another_rule_fifth">
+      <td><code>fifth</code></td>
+      <td></td>
+    </tr>
+  </tbody>
+</table>
+
 
diff --git a/src/test/java/com/google/devtools/build/skydoc/testdata/multiple_files_test/input.bzl b/src/test/java/com/google/devtools/build/skydoc/testdata/multiple_files_test/input.bzl
index b331e602c2..efd5ed460c 100644
--- a/src/test/java/com/google/devtools/build/skydoc/testdata/multiple_files_test/input.bzl
+++ b/src/test/java/com/google/devtools/build/skydoc/testdata/multiple_files_test/input.bzl
@@ -4,7 +4,8 @@ my_rule = rule(
     implementation = my_rule_impl,
     doc = "This is my rule. It does stuff.",
     attrs = {
-        "first": attr.label(mandatory = True, allow_files = True, single_file = True),
+        "first": attr.label(mandatory = True, doc = "first my_rule doc string",
+                            allow_files = True, single_file = True),
         "second": attr.string_dict(mandatory = True),
     },
 )
@@ -13,7 +14,8 @@ other_rule = rule(
     implementation = my_rule_impl,
     doc = "This is another rule.",
     attrs = {
-        "third": attr.label(mandatory = True, allow_files = True, single_file = True),
+        "third": attr.label(mandatory = True, doc = "third other_rule doc string",
+                            allow_files = True, single_file = True),
         "fourth": attr.string_dict(mandatory = True),
     },
 )