[css-text-3] Allow first/last to hang colons (and dashes?)

[fantasai]

In https://lists.w3.org/Archives/Public/www-style/2015Mar/0150.html @bradkemper wrote:

I would like the characters that can hang on the end of a line to include a colon. The use case is common when you have right aligned labels ending in a colon. It looks weird when the lines wrap and the last word doesn't line up with the other words.

Could colons be part of the hanging characters in 'hanging-punctuation: last'? Or could there be a new value, such as 'hanging-punctuation: last-loose', that hangs the characters in the [Po] category?

Background Info: The end value of hanging-punctuation is intended for CJK, and the first value, in conjunction with text-indent, was needed also for CJK https://www.w3.org/TR/jlreq/#positioning_of_opening_brackets_at_line_head But first in conjunction with last gives useful behavior for Western typesetting as well, such as for pull-quotes. The question here would be, does adding more punctuation to the hangable classes of last interfere with any existing use cases? If so, we need a new value. If not, we can fold it into last.

The other question is, which characters, specifically, need to hang like this?

[bradkemper]

Dashes (maybe slashes too) can be used in the same way as colons, to separate the thing on the left from the thing on the right, where the thing on the left is text-align: right and you want the alphanumeric characters to be aligned. Wrapping phone numbers that have dashes in them, in a very narrow column, I think it would be nice to have the numbers align on the right and the dashes sticking out. Any chance of letting the characters that hang be author-specified?

[css-meeting-bot]

The Working Group just discussed hanging-punctuation: last and colons and dashes, and agreed to the following resolutions:

• RESOLVED: Defer this to L4

The full IRC log of that discussion

<fantasai> Topic: hanging-punctuation: last and colons and dashes
<fantasai> https://drafts.csswg.org/css-text-3/issues-lc-2013#issue-170
<fantasai> github: https://github.com//issues/2392
<dael> fantasai: brad kemper asked if we can hang the colon. I thought and if we wanted to hang colons with the end values that's a problem but we can do it for the last value and prob would work. Do we want colors and maybe dashes to be paintable?
<dael> myles: We had a long discussion on this.
<dael> fantasai: This is the last line, that was end value. Last line has different behavior and so we want them to be hangable there.
<dael> myles: Don't want new issues for every new character, there should be named sets.
<dael> fantasai: Dashes are easy as a set in unicode.
<dael> myles: I mean, I'm writing an english novel and I want the things english novels hang.
<dael> astearns: You would have missed brad's use case.
<dael> fantasai: I think we could do customizable sets some day.
<dael> myles: I don't think these sets should be desc in CSS prop. The spec should have a handful of common sets.
<dael> fantasai: The default set. Does it include colon? We have ar eason to include. A reason not to?
<dael> myles: The sets of characters are designed for cjk.
<dael> fantasai: First and last are all languages. End is CJK. I don't expect them to use last because they'll use end. Should that set include colons and dashes?
<dael> myles: What's I'm desc is the set has a list of characters. You want to add t the list. I think instead of one list we add to we should have general sets.
<dael> fantasai: We can do that. But the property defining those sets need to have values.
<dael> myles: THe set I see here is designed for one typographic use case.
<dael> astearns: Are you asking when we add this new set it's disctinct in the spec? When we add this it'll be in a set
<dael> myles: It can be add both sets.
<dael> astearns: You're asking for things t o be added in sets based on use cases?
<dael> myles: Yes. I think we should consider this at higher level. For this use case hang these. And this use case hang these.
<dael> astearns: For fantasai we need a default.
<dael> myles: Colon doesn't fit in the current sent.
<dael> fantasai: You're looking at the set for end. The last is a bunch of large punct categories. Do we add more which is colons and dashes.
<dael> koji: I share myles concerns. THe property was defined first for CJK so there's a lot of CJK. If we want to support latin hanging punct we should think about a proper set of hangingin punct for latin.
<dael> fantasai: WE didn't want to do margin in L3 but first and last is in L3.
<dael> fantasai: I would ask the question, there's clear use cases for hanging colons and dashes. Is there a reason why we shouldn't?
<dael> koji: We don't know what the design should be when this property includes other scripts. Doing that right now may conflict.
<dael> astearns: Not sure I agree. I think you have to give evidence that adding colons and hypens to the sets would break CJK layout.
<dael> koji: As fantasai said last isn't used in CJK. First is for CJK, last is for latin.
<dael> fantasai: We're asking to change the set of characters in last to include more characters.
<dael> koji: I think we will have more characters. I wish us to start thinking about hanging punct in a seious way.
<dael> florian: Remove last until we know what we'll do with it?
<dael> myles: There is an impl, at least one. Prop is don't touch for now and have a more ellaborate extension in next spec level
<dael> astearns: Defer this to text level 4 is proposal
<dael> fantasai: I feel that every time we talk hanging punct people gets confused. I'm trying to distinguish hanging punct at end of every time vs that you do at beginning of first and end of lsat line. It's a different set of characters.
<dael> fantasai: You want to pull out the quotation mark from the outside of the start of the paragraph, but you wouldn't want to do it anywhere else. It's a different set of characters and a different feature.
<dael> florian: And within that set these characters make sense.
<dael> astearns: In the perms I'm familiar with optical magin alignment is the thing in text 4 and hanging punct is what's in L3. But I don't know if my concept of hanging punct in roman can extend to CJK.
<dael> florian: For you would colon and dash be included?
<dael> astearns: Yeah.
<dael> fantasai: We're solving 2 use cases in L3.
<dael> astearns: We don't have to have a complete feature in a module. That we're close to CR makes me hesitant to add more things.
<dael> florian: THis new character solves the second feature better. SHould it be incomplete in L3?
<dael> astearns: Yes because we have an impl and we can refine in a future level.
<dael> fantasai: But it's a change in behavior, not an addition.
<dael> koji: I think colon and dash isn't a significant difference to add i nL4
<dael> florian: We'd have to revise l3
<dael> koji: Future level can change past features.
<dael> florian: It means you can't conform to both.
<dael> myles: When you impl hanging punct there will be tests to say don't hang anything not in this list?
<dael> florian: Yes. You should test these character and only these characters hang.
<dael> astearns: That the spec says UA may include other characters as appropriate makes me think this is extensible.
<dael> astearns: I prefe to defer.
<dael> fantasai: It's fine, but we'll discuss in Sydney.
<dael> astearns: I'd like to go into more details on the set in L4
<dael> astearns: Obj to defer to L4?
<dael> RESOLVED: Defer this to L4