Add another paragraph to the 6th part of the compiler series

content/blog/06_compiler_semantics.md

@@ -87,5 +87,18 @@ $$
 \\mathcal{C} ⟦f⟧ \; \\rho = [\\text{PushGlobal} \\; f]
 $$
 
-Next up, case expressions. These are a bit more complex: there are several
-branches, each of which will have its own environment.
+Now it's time for us to compile case expressions, but there's a bit of
+an issue - our case expressions branches don't map one-to-one with
+the \\(t \\rightarrow i\_t\\) format of the Jump instruction.
+This is because we allow for name patterns in the form \\(x\\),
+which can possibly match more than one tag. Consider this
+rather useless example:
+
+```
+data Bool = { True, False }
+defn weird b = { case b of { b -> { False } } }
+```
+
+We only have one branch, but we have two tags that should
+lead to it!
+