Generate correct markup for selected options.

[emezeske]

Previously, each had a "selected=..." attribute, with its value set to true or false depending on whether it was supposed to be selected. Browsers interpret this to mean that we want them all to be selected. The correct behavior is to leave out the "selected" attribute for all but the element that is to be selected.

Note that I also amended the tests to make sure that this works properly.

[weavejester]

Hiccup interprets boolean values in attributes differently from strings:

user> (select-options [1 2 3] 3)
([:option {:selected false} 1] [:option {:selected false} 2] [:option {:selected true} 3])

user> (html (select-options [1 2 3] 3))
"<option>1</option><option>2</option><option selected=\"selected\">3</option>"

user> (html [:option {:selected true} 3])
"<option selected=\"selected\">3</option>"

user> (html [:option {:selected false} 1])
"<option>1</option>"

So the behaviour is already correct. No need for this patch.

[emezeske]

Interesting! I ran into this problem with crate, first, and fixed it there before cross-porting the fix to hiccup. I assumed that it was a problem here too, because I did not know about this behavior.

I patched it the same way in crate. Now I'm thinking that I should take a look at crate's boolean attribute handling, which (I guess) does not work this way. I probably should fix that instead of handling things specially for select-options.

Thanks for the quick feedback on this!