Allow sourcing in blockquote markdown

Question

A blockquote nearly always comes with a source, however the way to format the quote often differs:

• Some people will put the link like this (http://www.example.com)

• Others will put it like this.
  http://www.example.com

• It's also commonly hidden in one of the links that come in front of the blockquote...

  ... which can sometimes be really confusing though works quite well most of the time.

• Then you have people who prefer this.

  Source: http://www.example.com

• or the same thing, but without the "source" in front which looks kinda bad again.

  http://www.example.com

• And I have even seen this which looks pretty neat, but uses HTML.
  _{Source: http://www.example.com}

• Or maybe like this which is so bad that I tend to actually 'fix' this, as it's relatively hard to read the light blue text on a yellow background

Either way, this got me thinking that in UBB the formatting is done for you like this normally:

[quote=http://www.example.com]The quote[/quote]

Which tends to format the source URL in a consistent way in the blockquote. For example something like number 5 above, however right aligned like below.

An example of how this could theoretically look, however do note that 1) I am not a designer, 2) I used  's to format it this way in this preview and 3) the spacing is a bit off as I used <sub> to get the font size different.
                                                                                                       _{source: http://www.example.com}

Which in turn got me thinking whether it wouldn't be a good idea if a similar option would be included in SE markdown.

Concrete proposal

It's far harder in markdown to think up a good syntax than it is in UBB, but I would personally suggest an empty line (just >) and then on the last line of the blockquote the literal string > Source: followed by the source (which can be either an URI, a full markdown link or just text), thus giving:

> blockquote
>
> Source: http://www.example.com

Following the markdown design goals this is fully readable in plain text, it picks up already some of the currently used syntax, but is explicit enough that it should never catch anything it shouldn't have caught. The alternative is dropping the line outside the blockquote like

> blockquote

Source: http://www.example.com

Though I am personally inclined to prefer the first option as the relationship is slightly more explicit.

As far as interaction with the editor goes and the “-button, I would suggest that the > Source: line is included by default if clicked without an selection and triggers an error if left empty (the user should either remove the line or enter a source). If the user already has selected a text it could trigger a simple prompt dialog to ask for the source/attribution.

Now, in regards to (further) diverging from the standard: It's important to realize that blockquotes are a first class citizen in the way SE is used. Where one will not find a lot of blockquotes in typical markdown usage (being code), on SE you will find hundreds of thousands of them. And the good thing about this proposed syntax is that it follows markdown philosophy so well that it won't even actively look bad if parsed in an actual standard-abiding markdown parser (it would just look better on SE). (And yes, I am aware commonmark exists, but I am not sure where that project is realistically heading~)

PS. Whilst writing this proposal I found out that 5 years ago somebody brought up this issue in the context of quoting other users and mostly without a concrete proposal. Considering it's 5 years later and this is a far more specific proposal I decided to post it separately like this.

Answer 1

I recently brought up this topic on Meta ELU, Citation/attribution for quote in blockquote on ELU. In the course of investigating before posting about the issue, I discovered that the W3C HTML5 recommendation of October 2014 addresses citations/attributions within blockquotes.

The cite attribute of blockquote suggests one approach; however, the cite element is more versatile than the cite attribute, being extensible by class to author, title, url, etc. For coding examples covering a variety of attribution types and contexts, see the discussion in "4.4.4 The blockquote element" of the W3C recommendation.

The responses to my post on Meta ELU confirmed the point that Markdown as implemented on SE doesn't currently support either the cite element or the cite attribute, and suggested that support for those should be requested on SE. Further, use of something like

> quote
> 
>? attribution

in Markdown was suggested in the responses, along with the implementation of an appropriate style rule or rules. The Markdown as suggested and shown above could be transformed to this HTML,

<blockquote>
quote
<cite>attribution</cite>
</blockquote>

then rendered appropriately by style rules, perhaps resulting in something like this:

quote

— attribution

Elaborations of the foregoing are more to my taste (although quite possibly to the taste of few others), for example

> quote
> 
>?a author of source
>?d date of source
>?t title of source
>?u url of source

where any or all of a, d, t, and u are optional. This Markdown might be transformed to HTML such as

<blockquote>
quote
<cite class="author">author of source</cite>
<cite class="date">date of source</cite>
<cite class="title">title of source</cite>
<cite class="url">url of source</cite>
</blockquote>

SE style rules could then govern how the quote and its attribution would be rendered.

Answer 2

Nice idea! I would like it to "trigger" when the whole blockquote is a link, e.g.

[>The quick brown fox jumps over the lazy dog](https://en.wikipedia.org/wiki/The_quick_brown_fox_jumps_over_the_lazy_dog)

Which right now renders as:

>The quick brown fox jumps over the lazy dog

And instead would be cool to have it as:

The quick brown fox jumps over the lazy dog
                                                                                                                                              _(source)