Comments on: Grammar Question

By: Mary

Mary — Fri, 03 Feb 2006 14:43:20 +0000

Is the title of a play underlined or in quotes? Thank you for your assistance.

By: Eric

Eric — Sun, 19 Sep 2004 12:36:40 +0000

Okay, it's much more clear now—thanks to all.

J.B.: yep, you're right, that's more in line with what I meant to say, although I realized later that my formulation didn't permit single-quote marks, and in turn neither did yours, but you were a lot closer to being correct than I was. As for the outsider-hostile character encoding, I figure that anyone who needs to encode markup will know how to do it; nobody else would really need to know anyway. One of these days I'll probably add a preview function, but there are a lot of other things sitting much higher on my priority list. With any luck, WordPress will get a comment-preview function built in, and that will be that.

By: J.B. Nicholson-Owens

J.B. Nicholson-Owens — Sun, 19 Sep 2004 07:17:06 +0000

By the way, I don’t think “[ '"'? IDENT '"'? ]” means what you think it means, Eric. I think it means that EACH quote is optional, not BOTH quotes TAKEN TOGETHER. The subtle difference is illustrated here; with your syntax all of the following 4 are legal:

“hello” (quotes on both ends — you thought of this)
“hello (quote on left only)
hello” (quote on right only)
hello (no quotes at all — you thought of this)

I think what you were going for is

[ '"' IDENT '"' | IDENT ]

which indicates a choice: quotes-on or quotes-off, you supply both quotes or no quotes. No onesies.

Finally, telling people to “Remember to encode character entities if you’re posting markup examples!” without a preview button is rather “hostile-to-outsiders”, no?

By: jf

jf — Sun, 19 Sep 2004 02:24:57 +0000

String vs. ident: The choice between string and ident allows you to skip the quotes if it is a single, simple word (no space, punctuation or non-ascii). So class=abc and class="abc" are both legal, while class="to be" must be quoted. The historical reason is proably that html uses these rules. (Unlike xml/xhtml, where quotes/strings are always mandatory.) Strings do allow all characters, both ascii and non-ascii, with the newline/control char/quote exceptions. "string doesn't allow non-ascii characters" refers to "the flaw in the reasoning", not to strings.

By: David Baron

David Baron — Sun, 19 Sep 2004 02:16:03 +0000

Er, I did write a double negative, just not in the right two places. I meant “doesn’t disallow ASCII characters” (well, most of them). But I put a “non-” in front of “ASCII” instead of a “dis” in front of “allow”.

I should always read what I write to see any words out!

By: David Baron

David Baron — Sun, 19 Sep 2004 02:14:11 +0000

Oops, I was trying to write a double negative and I forgot one of them. I meant "doesn't disallow". And the reason simple STRING doesn't suffice is that we want to allow td[align=left] in addition to td[align="left"], as long as the attribute value is reasonably simple (i.e., an identifier).

By: Eric

Eric — Sun, 19 Sep 2004 00:32:36 +0000

The -~ bit pointed out by Antone seems to have been the missing key in terms of character-range. But why, then, offer a choice of a STRING or IDENT, when it seems like a simple STRING would suffice? I still don't get that part. And then David said:

The flaw in the reasoning in the post is, as pointed out above, that STRING doesn

By: David Baron

David Baron — Sat, 18 Sep 2004 20:20:05 +0000

The flaw in the reasoning in the post is, as pointed out above, that STRING doesn’t allow non-ASCII characters. In fact, it allows all characters except for unescaped newlines, the type of quotation marks quoting the string (unescaped), and control characters other than TAB (i.e., all characters less than ASCII/Unicode 32 other than TAB, plus ASCII/Unicode 127).

That said, it should be possible to figure this out without looking at the grammar. The attribute selector part certainly is possible: 5.8.1 says “Attribute values must be identifiers or strings.” The definitions of identifiers and strings, though, should probably be clearer in chapter 4.

By: Laurens Holst

Laurens Holst — Sat, 18 Sep 2004 19:15:51 +0000

Because CSS 2.1 is more based on real-world implementations and lessons learned from CSS 2. It is the better spec (especially as far as clarity of explanations is concerned), and the one most browsers aim to implement.

~Grauw

By: Jim Dabell

Jim Dabell — Sat, 18 Sep 2004 17:27:02 +0000

Is there any particular reason you are quoting from CSS 2.1 and not CSS 2? The definition of attr is the same, and the 2.1 specification states:

“Publication as a Candidate Recommendation does not imply endorsement by the W3C Membership. It is inappropriate to cite this document as other than work in progress.”

By: Uri Bernstein

Uri Bernstein — Sat, 18 Sep 2004 16:09:41 +0000

Alway one step behind you :-)
I should refresh more often.

By: Antone Roundy

Antone Roundy — Sat, 18 Sep 2004 16:09:01 +0000

I don’t think ‘div[class=this is a test] {color: orange;}’, without quotes, is legal.

attrib : ‘[' S* IDENT S* [ [ '=' | INCLUDES | DASHMATCH ] S* [ IDENT | STRING ] S* ]? ‘]’

After the ‘=’, you can have 0 or more whitespace characters followed by exactly one ident or string followed by 0 or more whitespace characters (notice that there’s no “*”, “+” or anything after [ IDENT | STRING ], so you have to have exactly one of those). If you put quotes around “this is a test”, you have one string. Without the quotes, you have 4 identifiers.

By: Uri Bernstein

Uri Bernstein — Sat, 18 Sep 2004 16:08:31 +0000

Antone – I’m afraid you took the wrong turn in step 3 – you followed the rule for escaped characters (which consist of a backslash followed by something).

(the other reason I’m posting this comment is to correct my e-mail address, which I mis-typed last time).

By: Antone Roundy

Antone Roundy — Sat, 18 Sep 2004 15:57:32 +0000

Oops! Correction to what I wrote above. “escape” requires a backslash to precede it. The way you get the useful characters in there is from string1 (or string2) where is lists (-~ in the jumble of symbols. In this case, “-” denotes a range of characters, not a literal minus sign. The range (-~ includes almost everything in -~, just not ! ” # $ % & and ‘, all of which (except the quote marks) are listed literally.

By: Uri Bernstein

Uri Bernstein — Sat, 18 Sep 2004 15:54:55 +0000

Hi Eric,

I hope I can help here a bit and perhaps thus pay back for some of the help I got from your books and columns.

STRING, in fact *does* include the ASCII range (or most of it). The key to understanding this is that little “-” hiding there, near the end of [\t !#$%&(-~], in the definition of STRING. What it means is “any character whose code is between that of ‘(‘ (which is hex 28) and ‘~’ (which is hex 7E)”. This includes all the digits, lower and upper case letters, and some more.

So if your string qualifies as an IDENT (roughly mening that it starts with a letter or underscore, and does not contain unescaped spaces or punctuation), you don’t have to quote it. Any other string, you do have to quote.
Note that every IDENT also qualifies as a string (when quoted). So you’re always allowed to quote, if you feel like it.

At least that’s the way I understand it.