diff --git a/doc/grammar.rst b/doc/grammar.rst
new file mode 100644
index 0000000..b1021a4
--- /dev/null
+++ b/doc/grammar.rst
@@ -0,0 +1,9 @@
+DocBlock -> Directive | MarkdownBlock
+
+Directive ->
+    "@author" MarkdownBlock |
+    "@doc" MarkdownBlock |
+    "@example" MarkdownBlock |
+    "@org" LiteralString
+
+MarkdownBlock ->