Could be my bad, but I oft-times toss some HTML below the yaml front matter of .md content files. I also sometimes use {{ is_admin }} and other globals, conditionals, etc. Yet, some code that would work in my layouts and partials, etc. just went ker-flooey when pasted inside my markdown. Took me qui-i-i-i-te a while to figure this puppy out.
Turns out this blows up:
---
title: DEMO
---
{{ if "two" == "two" }}Right!{{ else }}Wrong!{{ endif }}
but this works:
---
title: DEMO
---
<code>{{ if "two" == "two" }}Right!{{ else }}Wrong!{{ endif }}</code>
What's going on in the first case is the markdown parser is changing those nice straight quotes around the literal into left and right curly-quotes, which, needless to say, greatly annoys our pal Slim:
You have a syntax error in your Lex tags. The offending code: <p>if (“null” == “null”): Right!else: Wrong!endif; </p>
Just off the top of my head, I'm not sure what I'm going to do about this, near term. I got a postcard from Work-Around Land saying that creating a global var in _config/settings.yaml, like _literal for "literal" does work, but... yeuck.