[jbmilgrom]

I don’t think that’s the right take. Poetry manipulates common grammatical rules and still communicates meaning from the writer to the reader, perhaps in an even deeper way because of that manipulation. Of course in Java and many other programming languages, grammatical errors will simply not compile. LISP is one of those few languages where grammar can change from program to program, much like with poetry

[mightyham]

Even though there is much more freedom in poetry, it is still defined by a specific set of rules/features: verses, rhythm, stanzas, spacing, meter, and rhyming. It's only because of these restrictions that it is so obvious when writing is or isn't poetry. These features and forms can streched, but unlike lisp they cannot be completely redefined.

[KerrAvon]

You’ve got to read more poetry before making assertions like this. In practice, the definition is more fluid than that.

Lisp cannot be completely redefined. You can’t avoid parentheses, and if you stray too far from common idiom, you’re no longer writing Lisp, you’re writing something else using Lisp syntactic forms.

[KineticLensman]

> It's only because of these restrictions that it is so obvious when writing is or isn't poetry. These features and forms can streched, but unlike lisp they cannot be completely redefined.

I disagree here. To take rhyming as an example. It's possible to have a poem where every line rhymes AND a poem where there is no rhyme at all. It's not as simple as saying 'okay the lines in this text don't rhyme so it can't be a poem'. The same is true of the things like spacing and meter. These are all massively variable, and the result doesn't even have to be bound by the usual rules of grammar. English - or any other natural language - is much more variable than Lisp.

For me the defining feature of poetry is that the form and nature of the language used in a text may suggest meaning over and above what the individual words say. This definition is subjective, and suggests that the poetry is in the eye of the beholder, but is more honest than a simplistic checklist of features to look out for.