[web-devel] [hamlet] implicit spaces with newlines?

Patrick Brisbin pbrisbin at gmail.com
Fri May 20 17:22:42 CEST 2011


On 05/20/11 at 11:12am, Daniel Patterson wrote:
> I think what the original author was saying was that when you make a new line with html, whitespace is inserted, not whether hamlet should automatically insert space after every tag.
> 
> So yes, writing <p>hello<strong>there</strong></p> should not put white spacing. 
> 
> But when you write, in html:
> <p>hello
>     <strong>there</strong></p>
> 
> It is equivalent to <p>hello <strong>there</strong></p> (note the space). 

Isn't that simply due to the fact that HTML compresses whitespace across 
the board? (turning that "\n\t" or "\n    " into just " ")

Leading spaces in hamlet are used to define nesting, so also compressing 
this whitespace (rather than stripping it) would produce odd effects:

  <div>
      <p>Hey
          <strong>there

Would turn into

  <div> <p>Hey <strong>there</strong></p></div>

Which has an unneeded space after the parent <div>

Right?

> 
> 
> On May 19, 2011, at 11:57 PM, Michael Snoyman wrote:
> 
> > On Thu, May 19, 2011 at 11:49 PM, Patrick Palka <patrick at parcs.ath.cx> wrote:
> >> I find it a bit unintuitive that the hamlet code
> >> 
> >> <p>hello
> >>    <strong>there
> >> 
> >> or
> >> 
> >> <p>
> >>     hello
> >>     <strong>there
> >> 
> >> generates the html
> >> 
> >> <p>hello<strong>there</strong></p>
> >> 
> >> I expected there to be a space between "hello" and "there" similar to what
> >> the html specifications dictate. Is this behavior intentional or an
> >> oversight? If it's the former, then what is the recommended way to simulate
> >> my expected behavior? Appending a space to the end of a line is
> >> mentally ugly and syntactically obscure.
> > 
> > I'm not sure what you mean by "what the html specifications dictate."
> > HTML is whitespace-sensitive, meaning that:
> > 
> >   <i>foo</i> <b>bar</b>
> > 
> > and
> > 
> >    <i>foo</i><b>bar</b>
> > 
> > Are different. Now, in all likelihood in the above example, you will
> > want to have the whitespace surrounding tags. But consider the
> > following HTML:
> > 
> >    <p>You are logged in as <i>Michael Snoyman</i>, <a
> > href="/logout">logout</a>.</p><p>Another paragraph.</p>
> > 
> > In the case of the <i> and <a> tags, we definitely do *not* want to
> > add whitespace after the tag (though we do want it before the tag). In
> > the case of <p>, we don't care one way or another, but adding the
> > whitespace everywhere will take up (a trivial amount of) extra
> > bandwidth. tl;dr: Sometimes you don't want the whitespace.
> > 
> > So when designing Hamlet, I thought up a few possibilities:
> > 
> > 1) What we do now: all whitespace must be explicit.
> > 2) Implicitly add whitespace before/after every tag.
> > 3) Do something "smart", adding whitespace where it's desired.
> > 
> > (2) isn't really an option because it makes having a tag as the last
> > word in a sentence impossible. (3) gives me the creeps: I like smart
> > libraries, but I will *never* trust a library to do this kind of stuff
> > correctly all the time, even if I'm the one making up the rules for it
> > to follow! And I have no doubt that it will quickly devolve into 500
> > lines of hairy code to try and cover millions of corner cases. Oh, and
> > don't forget that there are other languages than English that might
> > approach it differently.
> > 
> > I suppose another possibility is (2) along with some special way of
> > forcing the removal of extra whitespace, but this seemed much less
> > intuitive than the current approach.
> > 
> > Anyway, that's the reasoning behind this stuff, if people have better
> > ideas, I'd like to hear them.
> > 
> > Michael
> > 
> > _______________________________________________
> > web-devel mailing list
> > web-devel at haskell.org
> > http://www.haskell.org/mailman/listinfo/web-devel
> 
> 
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-- 
patrick brisbin



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