"Prosaic license"? If the essay was written in iambic pentameter, it certainly escaped me. Anyway, "C++ macro language with striking similarities" has a pretty precise technical meaning, which sane, literate people might actually mistake.
"poetic license" isn't the same as "poetic."
From the free dictionary:
poetic license
n.
The liberty taken by an artist or a writer in deviating from conventional form or fact to achieve a desired effect.