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

Daniel Patterson lists.haskell at dbp.mm.st
Fri May 20 17:12:00 CEST 2011


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). 


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
> 
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