answer deleted; I misunderstood your question

Remember that for "paragraphs" over a certain number of characters -- pretty low, as I remember -- InDesign reverts to the single line composer mode.

Otherwise, just search for end of paragraph & replace it with a space of some sort, a pilcrow, and another space.

Not what you asked, but I don't see the issue of doing this globally. Then go back & put in whatever paragraphing you do want.

If you want it global & semiautomatic, just set up a grep search/style. However, at some point, you'll probably want an end of paragraph, so I'd advise against this.

I wonder if there are any layout applications that offer this as an option?

The answer is there is no way to do this automatically — in real time — in InDesign. I.e., you can't do an on-the-fly search-and-replace to change hard returns to something else. A GREP style won't do it, and there's annoyingly no "real time" search-and-replace feature.

For one brief moment of hope, I thought AutoCorrect might help you out, but you can't enter a return as a character in AutoCorrect. Returns sort of have their own special rules.

I.e., you can't do an on-the-fly search-and-replace to change hard returns to something else

???
We get in manuscripts all the time that use the following coding

... sdfkjg azsdfkl aslkdf awelt asdfj asdrfkgj aslkj asdflkj aweotu awet aslkdfj asldfkj
{A}
This is an A-subhead
{txt} aweroptu aqtrwiu sdfkjg azsdfkl aslkdf awelt asdfj asdrfkgj aslkj asdflkj aweotu awet aslkdfj asldfkj

OK. I want to apply paragraph styles globally. I first search for

{A}
and throw out the return, so it is on the same line a the text proper, e.g.,

{A}This is an A-subhead

Done by searching for {A} & the special end of paragraph wildcard token, and replacing it with only {A}

To finish the story... I then search for the character {A} with a paragraph style of "text" and replace the paragraph style with "Ahead".

One more search to dump the code {A}.

All done with "find and replace," it takes very little time for a chapter ("story" in InDesign) or even an entire book ("all")

But the first step was knocking out that unwanted hard return, so the {A} code was in the same paragraph as the text of the subhead.

While I'm home & haven't tested it exactly, I'm 99.44 &% sure you can do that & replace the hard return with a pilcrow & spaces, using either "selection", "story", or "all" ("all" probably not a smart choice...)

Yes, of course you can do a search-and-replace.

I said you can't do it "on the fly" — i.e., you can't set it up so every instance of a hard return automatically becomes a sequence of pilcrow surrounded by spaces every time it's typed, without actively executing a search and replace.

In other words, a GREP search will work, but a GREP style won't.

The original poster specifically asked if you can do this "without having to search and replace it."

The answer is no, unfortunately you can't.

Maybe if you write a plug-in?

hhp

Thanks for all the feedback, i guess i should stick with the find and replace then, but it would be a good thing for the next version of InDesign or some plug-in, unfortunately i don't have the coding skills for that...