Why is libtidy complaining <data> isn’t approved by W3C?

[jonnybarnes]

It is: https://www.w3.org/TR/html5/text-level-semantics.html#the-data-element

What does “approved by W3C” mean?

[geoffmcl]

@jonnybarnes thanks for the issue...

It is usually better, and certainly faster testing, if you supply a minimal sample html, which should pass the W3C validator... but I was able to construct one quite quickly using the sample code given here...

Why is libtidy complaining <data> ...

In a quick read of the TR given, and others found, can only say just an oversight!

It seems that element should be supported... but there is presently no TidyTag_DATA enumerated, and defined in tags.c... so libtidy will bark loudly ;=))

Will get to it, if no one beats me to it, but meantime look forward to a patch, or PR... thanks...

[balthisar]

On that note, I wonder if we should update that message per se, given that the WHATWG essentially define what HTML5 (and beyond) is. Not long ago, I was trying to understand, "why 'voyager'?" (our XHTML flag), and it took me down a rabbit hole of who defines the specification these days.

WHATWG is affiliated with the W3C (currently), and they only apply to HTML5, so leaving things alone is certainly the easiest...

[geoffmcl]

@balthisar not sure I understand your comment... maybe you can clarify...

If you run default tidy, my 5.5.84, on my sample, in_649.html, you will get -

line 12 column 23 - Error: <data> is not recognized!
line 12 column 23 - Warning: discarding unexpected <data>
line 12 column 44 - Warning: discarding unexpected </data>
etc

If you run that tidy adding --new-blocklevel-tags data you will get -

line 12 column 23 - Warning: <data> is not approved by W3C
...repeated...

I assumed @jonnybarnes was referring to the second message... if not, hope he too will clarify... and supply some sample code...

Which message do you refer to in I wonder if we should update that message per se? Update it to what exactly...

And then why do you add leaving things alone as an option?

That sample in_649.html validates without a problem, and per the TR and WHATWG pages, <data value="123"> is valid HTML 5... How can we leave things alone?

Anyway, given that nothing has been done on this yet, that I know of, am moving the milestone out to the next release...

But certainly feel tidy should support this <data value="123"> element... thanks...

[balthisar]

I meant, leave my additional suggestions alone, i.e., not change the message.

[jonnybarnes]

Yes, I was referring to the second message.

[antonioshadji]

I edited tags.c and tags.h to include the <data> tag but it does not compile on my machine. I would like to submit a PR if I can get it working.

the changes I made to the code are just three lines.

diff --git a/src/tags.c b/src/tags.c
+#define VERS_ELEM_DATA       (xxxx|xxxx|xxxx|xxxx|xxxx|xxxx|xxxx|xxxx|xxxx|xxxx|xxxx|xxxx|xxxx|HT50|XH50)

+  { TidyTag_DATA,        "data",         VERS_ELEM_DATA,        &TY_(W3CAttrsFor_DATA)[0],        (CM_INLINE),                   TY_(ParseInline),    NULL           },
   
diff --git a/src/tags.h b/src/tags.h
+#define nodeIsDATA( node )       TagIsId( node, TidyTag_DATA )

When I compile, I'm getting these errors:

[  8%] Building C object CMakeFiles/tidy-share.dir/src/tags.c.o
/mnt/projects/oss-contrib/tidy-html5/src/tags.c:306:5: error: ‘TidyTag_DATA’ undeclared here (not in a function); did you mean ‘TidyTag_META’?
   { TidyTag_DATA,        "data",         VERS_ELEM_DATA,        &TY_(W3CAttrsFor_DATA)[0],        (CM_INLINE),                   TY_(ParseInline),    NULL           },
     ^~~~~~~~~~~~
     TidyTag_META
In file included from /mnt/projects/oss-contrib/tidy-html5/src/config.h:35:0,
                 from /mnt/projects/oss-contrib/tidy-html5/src/tidy-int.h:12,
                 from /mnt/projects/oss-contrib/tidy-html5/src/tags.c:11:
/mnt/projects/oss-contrib/tidy-html5/src/forward.h:23:29: error: ‘prvTidyW3CAttrsFor_DATA’ undeclared here (not in a function); did you mean ‘prvTidyW3CAttrsFor_META’?
 #define TY_(str) TYDYAPPEND(prvTidy,str)
                             ^
/mnt/projects/oss-contrib/tidy-html5/src/forward.h:22:31: note: in definition of macro ‘TYDYAPPEND’
 #define TYDYAPPEND(str1,str2) str1##str2
                               ^~~~
/mnt/projects/oss-contrib/tidy-html5/src/tags.c:306:66: note: in expansion of macro ‘TY_’
   { TidyTag_DATA,        "data",         VERS_ELEM_DATA,        &TY_(W3CAttrsFor_DATA)[0],        (CM_INLINE),                   TY_(ParseInline),    NULL           },
                                                                  ^~~
CMakeFiles/tidy-share.dir/build.make:158: recipe for target 'CMakeFiles/tidy-share.dir/src/tags.c.o' failed
make[2]: *** [CMakeFiles/tidy-share.dir/src/tags.c.o] Error 1
CMakeFiles/Makefile2:67: recipe for target 'CMakeFiles/tidy-share.dir/all' failed
make[1]: *** [CMakeFiles/tidy-share.dir/all] Error 2
Makefile:151: recipe for target 'all' failed
make: *** [all] Error 2

I can't figure out why I'm getting message ‘TidyTag_DATA’ undeclared here (not in function)
it seems to be declared the same as the other tags in tags.h.

[geoffmcl]

@antonioshadji thanks for looking at this...

A brief look at the 3 lines of code added, these are good but some more things are required...

The README TAGS may help a bit, but it too could/should be expanded... I will think about doc additions, but maybe there are not too many more to add...

As it suggests, the first thing to create a new HTML tag, is to add an item to tidyenum.h, in the following enumeration -

/** Known HTML element types
 */
typedef enum
{
  TidyTag_UNKNOWN,       /**< Unknown tag! Must be first */
  TidyTag_A,             /**< A */
  /* skip to bottom */
  TidyTag_DATA,          /**< DATA */
  
  N_TIDY_TAGS            /**< Must be last */
} TidyTagId;

Note, I do not think this list need be kept in alphabetical order... it is a unseen enumeration value...

Then your addition to tag_defs[] table in tags.c will be ok, nearly...

You will also need to define a set of attributes allowed on the NEW element, in attrdict.h/c, namely a const AttrVersion TY_(W3CAttrsFor_DATA)[] = { }; array of attributes, which must be terminated with { TidyAttr_UNKNOWN, 0 }... the Content Attributes: gives a clue to what must be added...

Maybe see W3CAttrsFor_DATALIST, and all the others as examples...

Then it should compile... you have made a good start... but there may be some question about the tag_defs entries... hope this helps in the continuation... thanks...

[antonioshadji]

Thank you, @geoffmcl Your comments were most helpful. I have added the tag and compiled successfully on ubuntu 18.04. I have tested on an html page with data elements and received no warnings or errors. I have created a pull request

I realized that I need to look at the ATTRIBUTES.md as well as TAGS.md for the full picture of what was required.

[geoffmcl]

@antonioshadji sorry for the delay in attending to this... and thanks for PR #769...

In a quick re-read of the patch, it certainly looks good... has anyone, else, pulled, built, and tested this?

Am catching up on outstanding PR's, and now considering #769, and would appreciate any comments, feedback, updates, testing, ... etc, of this issue... thanks..