, `|%` for
, `|+` for
# `||` and `|!` are for putting code blocks in an mdl document.
mdl uses `quack` (provided as a parameter to the exported `mdl` function)
to parse these blocks instead of mdl itself,
meaning code like `a * b \* c` doesn't need to be escaped.
this type of block must be closed with (and therefore cannot contain) a blank line.
`|!` will create a live