In the beginning was RUNOFF from MIT, which originally had about the power of Markdown. More features were added, and it became nroff, then troff, the ditrofff, and macro systems were added on top of it. It became too hard to use for casual work.
Then there was TeX, which was a saner approach to what troff did. Macro systems were added on top of it. It became too hard to use for casual work.
Then there was HTML, which started out with about the power of Markdown. More features were added. It became too hard to use for casual work.
Then there was BBcode, which started out with about the power of original HTML. It didn't gain many features, and is still widely used.
Then there was Markdown, which started out with about the power of original HTML. More features were added. Macros have been added by at least five people, but haven't quite gone mainstream yet. When Markdown gets macros, it, too, will be too hard to use for casual work.
Also, the silly space-at-the-end for line breaks.
They work like standard Markdown links (text in square brackets, followed by link in parens), except you add a bang in front of it. The bang looks like an upside-down "i", the first letter of "image".
Edit: read too fast; _links_ to images use image instead of text in a link, so you just replace the text with text in square brackets with the syntax of Markdown image. I've never struggled too much with this one, so I don't have any useful mnemonics, sorry.
I thought it was two spaces at end of line for a line break. Or did the one-space-at-end-of-line argument win?
And since my editor strips newlines on save (and no, I will not turn that feature off), I guess I can't use it.
It kind of scares me that I might inadvertently strip the newlines out of someone else's markdown that I'm editing, though.
There were some systems back in the DOS/early UNIX era which had significant EOL whitespace. Spaces at the end of a line are still significant following a "\" in shell files. Some early word processors under DOS had significant whitespace at EOL, but tended to display something like a paragraph mark when it mattered.
Python had tab/space trouble at beginnings of lines, but the compiler was finally fixed so that it emits an error if tabs and spaces are mixed in a way which makes indentation visually ambiguous. That was a neat solution to the problem.
Leading tabs in makefiles were a mistake. The author of "make" once wrote that he put that in, and then, the next day, realized it was a bad idea. But he already had a user base of three users and didn't want to change it and break their code.
I thought this idea was dead and buried. Sometimes, they come back.
It would make multiple repeated BRs difficult, though, but you probably shouldn't be doing that anyways.
Intriguing: significant white space on the right-hand side. At least you can see the significant whitespace in Python.
I also have my editor configured to strip trailing whitespace but also to highlight it. People can be very sloppy leaving (insignificant) whitspace lying around in code.
I left the conversation at that point because I sensed it might turn ugly (it was the afternoon, and he had a penchant for boozy lunches when his boss was out of the office).
: https://daringfireball.net/projects/markdown/syntax (see "Inline HTML")
My guess is that various syntaxes for doing basically the same thing fade in and out of popularity randomly and for the most part independent of their feature set, just as different ways of covering the body with cloth fade in and out of popularity. Last year's collection isn't unpopular because it became to hard to use, people want new stuff and they don't want to be associated with old stuff.
I use org-mode pretty exclusively, but it has the opposite problem of what you mention - it requires macros in your editor (maybe a set of Editor MACroS if you will..). This makes in unusable for anyone outside the emacs lifestyle.