Partially done railroad.js post

content/blog/2022/08/railroad-js/index.md

@@ -0,0 +1,37 @@
+---
+title: railroad.js
+slug: railroad-js
+date: 2022-08-20T10:45:53-07:00
+draft: true
+---
+
+{{< figures/railroad id="sExpressionDiagram" >}}
+    return rr.Diagram(
+        rr.Start("simple", "s_expression"),
+        rr.ZeroOrMore(
+            rr.Choice(0,
+                rr.Group(rr.Sequence(
+                    "a ... z",
+                    rr.ZeroOrMore(rr.Choice(0, "a ... z", "1 ... 9"))
+                ), "atom"),
+                rr.Sequence(
+                    "(", rr.OneOrMore(rr.NonTerminal("s_expression")), ")"
+                ),
+                rr.Sequence(
+                    "(",
+                    rr.NonTerminal("s_expression"),
+                    ".",
+                    rr.NonTerminal("s_expression"),
+                    ")"
+                )
+            )
+        )
+    );
+{{< /figures/railroad >}}
+
+I just recently integrated support for Tab Atkins' excellent [`railroad.js`][rrjs]. 
+It allows you to make diagrams like the one above. These are great for
+describing modular architectures, control flow through programs or other complex
+systems, and—as above—grammars.
+
+[rrjs]: http://tabatkins.github.io/railroad-diagrams/