Whitespace syntax

[alubbe]

This follows up on the syntax discussion started in #2075
Specifically, how can we improve on these hacks: #905 (comment)

My suggestion is to turn single empty lines into a whitespace and do nothing for two empty lines. Specifically,

a(href="...") Link1

a(href="...") Link2

yields

<a href="...">Link1</a> <a href="...">Link2</a>      NOTE the space between the tags

but

a(href="...") Link1
a(href="...") Link2

and

a(href="...") Link1


a(href="...") Link2

yield

<a href="...">Link1</a><a href="...">Link2</a>      NOTE there is no space between the tags

This change would be breaking some backwards compatibility. I have been trying to assess how big of an issue it is and have been asking for code examples from others that would be negatively affected - so far, I have not found any problems with it.

In my own projects, I use empty lines to seperate between "blocks" of markup. This could be the space between block, mixin, include or extend (no breaking change here), but also between actual blocks of html markup. These are almost always blocks like sections, container divs, paragraphs and the like - whitespace won't matter here. I would estimate the case of having empty lines separating inline or inline-block elements as somewhat rare, and of course, solvable by either removing that empty line or adding another.

What we would stand to gain is a very clean syntax that (I think?) no other white space based templating system has solved by such a simple mechanism.

[brandoncarl]

@alubbes @ForbesLindesay Have you guys considered a Markdown-style solution? Namely, two or more spaces at the end of an inline element would add a single space after the closing tag?

[s5b]

I find the trailing whitespace implementation in markdown to be a poor solution. Especially when many code editors are configured to (quite rightly) remove trailing whitespace. It's impossible to tell whether a line has trailing whitespace unless your editor has a way of displaying whitespace (some do), or you place your cursor at the end of each line you wish to inspect - tedious.

Placing a single whitespace character at the beginning of the following line appears to be a solution; especially with the | syntax.

While we're talking about whitespace, I see that the SCAML derivative of pug has whitespace control using trailing < characters. Are there plans for pug to support this syntax? Or am I missing something here?

[chrisnicola]

SLIM uses a similar solution < is preceding whitespace I believe and > is post.

That said using #[] syntax with a block does tend to solve this for most cases.

[buddyp450]

I'm personally for the pipe + whitespace character solution as it looks the most succient (I think) in the template markdown.