how to submit multi-line long form text to gemini?

[mbays]

* Friday, 2021-07-09 at 09:30 -0600 - Alex // nytpu <alex@nytpu.com>:

>> The thought occurred to me that using INPUT I could implement an edlin style text editor but I thought I'd sound this out before committing to that level of self-harm!
> I believe someone got ed(1) working through Gemini, and it's... better
> than nothing I guess.  The link is eluding me right now though.

You may mean this:
gemini://gemini.thegonz.net/gemrepl/examples/ed/

There's also this post suggesting using SMTP-style multiline input, with an example implementation linked from it:
gemini://gemini.thegonz.net/glog/210508-multilineInput.gmi