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

[Greg Weber]

Hi Anton,

Your message is a bit off topic for white space- maybe you meant to reply to
one of several other recent hamlet messages requesting more features. Adding
more features is not being ruled out, but we have concluded there is a need
for a hamlet that allows for *arbitrary* haskell, probably using this
package: http://hackage.haskell.org/package/haskell-src-exts-qq-0.4.0

Greg Weber

On Fri, May 20, 2011 at 6:30 AM, Anton Cheshkov <acheshkov at gmail.com> wrote:

> Is it possible to have multiline $with construction ? Sometimes i have many
> variables and very long line . Looks not pretty
>
> for example
>
> *$with  a <- func1 val, b <- func2 val, c <- func3 val*
> *          d <- func4  val*
> *    <p>{a}*
> *.....*
>
> Thanks.
>
> 2011/5/20 Greg Weber <greg at gregweber.info>
>
>> # render this:
>> <p>You are logged in as <i>Michael Snoyman</i>, <a
>> href="/logout">logout</a>.</p>
>> <p>Multi
>>   line
>>   paragraph.
>> </p>
>>
>>
>> # current - explicit
>> <p>You are logged in as #
>>   <i>Michael Snoyman
>>   , #
>>   <a href="/logout">logout
>>   .
>> <p>Multi
>>   \ line
>>   \ paragraph.
>>
>> # alternative #! - implicitly add space, explicitly remove on the next
>> line
>> <p>You are logged in as
>>   <i>Michael Snoyman
>>   ,
>>   <a href="/logout">logout
>>   !.
>> <p>Multi
>>   line
>>   paragraph.
>>
>>
>> # alternative #2 - implicitly add space, explicitly remove on the current
>> line
>> <p>You are logged in as
>>   <i>Michael Snoyman
>>   ,
>>   <a href="/logout">logout#
>>   .
>> <p>Multi
>>   line
>>   paragraph.
>>
>>
>> # alternative #3 - implicitly add space when there is a new line before
>> tag contents
>> # seems bad, just throwing it out there :)
>> <p>
>>   You are logged in as
>>   <i>Michael Snoyman
>>   ,
>>
>>   <a href="/logout">logout
>>   .
>> <p>
>>   Multi
>>   line
>>
>>   paragraph.
>>
>>
>> # alternative #4 - implicitly add space. remove space with 'whitespace
>> alligators'
>> # somewhat similar to:
>> http://haml-lang.com/docs/yardoc/file.HAML_REFERENCE.html#whitespace_removal__and_
>> # > chomps white space *after* the tag
>> # < chomps white space *within* the tag
>> # would need more examples to see if this plays out well
>> <p>You are logged in as
>>   <i>Michael Snoyman
>>   ,
>>   <a href="/logout">logout>
>>   .
>> <p>Multi
>>   line
>>   paragraph.
>>
>>
>> On Thu, May 19, 2011 at 8:57 PM, Michael Snoyman <michael at snoyman.com>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
>>>
>>
>>
>> _______________________________________________
>> web-devel mailing list
>> web-devel at haskell.org
>> http://www.haskell.org/mailman/listinfo/web-devel
>>
>>
>
>
> --
> Best regards,
> Cheshkov Anton
> Phone: +7 909 005 18 82
> Skype: cheshkov_anton
>
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