Binding and CSS Selectors input

[Pawel R]

Hi,

how can I get the input NodeSeq while CSS Selector Transformation?

When you use binding (def bind(xhtml: NodeSeq): NodeSeq = {...}) you can use xhtml argument. Using CSS Selector Transformation there are no arguments.

Thanks,

Etam.

[Diego Medina]

You can add the input field explicit.

Like here https://github.com/fmpwizard/lift-conditional-drop-down-menus/blob/master/src/main/scala/code/snippet/PlaceCometOnPage.scala

Sent from my cell
Diego Medina

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[Etam]

But there you have binding:

def render(xhtml: NodeSeq): NodeSeq = {...},

not a CssSel method like:

def render: CssSel = "*" #> "...".

[Diego Medina]

Ah, sorry about that, I have been staring at this one project for way too long.

I tried a few things and I could not tell how to do what you are
looking for, hopefully somebody will reply to this thread with the
correct answer.

regards

Diego

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[Naftoli Gugenheim]

Just pass the selectors a NodeSeq=>NodeSeq function.
def render = "*" #> {ns: NodeSeq =>
  "..."
}

Unfortunately it's not as nice if you want to nest selectors:
def render = "*" #> {ns: NodeSeq =>
  val ret = "button" #> SHtml.onSubmit(...)
  ret(ns)
}

Of course you could write that in other ways, like
def render = "*" #> {ns: NodeSeq =>
  (
    "button" #> SHtml.onSubmit(...)
  ) apply ns
}

And you can use CSS selectors inside the old method signature:

def render(xhtml: NodeSeq): NodeSeq = {

  "button" #> SHtml.onSubmit(...) apply bind("pre",xhtml,"other" -> "other")
}

The bottom line is that css selectors can take a NodeSeq=>NodeSeq, and they are one themselves.
And functions can be applied with parenthesis or by calling their apply method.

On Wed, May 18, 2011 at 1:14 AM, Etam <odwr...@gmail.com> wrote:

--

[Pawel R]

What I am trying to do is to take width and height parameters from <img /> tag (instead of S.attr) and pass them as Image.WIDTH_PARAM and Image.HEIGHT_PARAM in my Image model:

def cssSel = {

var width = S.attr("image_width").dmap(80)(_.toInt)

var height = S.attr("image_height").dmap(60)(_.toInt)

"img [src]" #> Helpers.appendParams(

Image.prefix + ResizeMethod.Fit.toString,

(Image.ID_PARAM -> "%d".format(id.is)) ::

(Image.WIDTH_PARAM -> "%d".format(width)) ::

(Image.HEIGHT_PARAM -> "%d".format(height)) :: Nil) &

"img [width]" #> width &

"img [height]" #> height

}

What is the best solution?

[Kristian Nordal]

Hi.

CssSel is a function from NodeSeq to NodeSeq, and the right hand side
of the expression can also be a NodeSeq => NodeSeq. You can do
something like:
"#foo" #> ((n:NodeSeq) => ...)

--
Cheers,
Kristian

[Etam]

Thanks Kristian, but it does not work.

[Etam]

If "CssSel is a function from NodeSeq to NodeSeq", how can you convert (in: NodeSeq) => NodeSeq to CssSel?

[Etam]

I have found the solution (isn't it too complex?):

def cssSelBind(in: NodeSeq): NodeSeq = {

val width = (in \\ "@width" text).toInt

val height = (in \\ "@height" text).toInt

val f = "img [src]" #> Helpers.appendParams(

Image.prefix + ResizeMethod.Fit.toString,

(Image.ID_PARAM -> "%d".format(id.is)) ::

(Image.WIDTH_PARAM -> "%d".format(width)) ::

(Image.HEIGHT_PARAM -> "%d".format(height)) :: Nil) &

"img [width]" #> width &

"img [height]" #> height

f(in)

}

def cssSel: CssSel = "*" #> {in => cssSelBind(in)}

Thanks for help.

[Naftoli Gugenheim]

You're making the assumption that there are no other width or height attributes in the snippet template!
Also, if the img tag has height and width attributes you don't need to reassign them. In Pawel's code he assigned them because he was reading them as snippet attributes.

What about:

def cssSelBind =
  "img" #> {(_: NodeSeq) match {case e: Elem =>
    val width = e.attribute("width").map(_.text) getOrElse "100"
    val height = e.attribute("height").map(_.text) getOrElse "100"
    val src = Helpers.appendParams(
      Image.prefix + ResizeMethod.Fit.toString,
      List(Image.ID_PARAM -> "%d".format(id.is), Image.WIDTH_PARAM -> width, Image.HEIGHT_PARAM -> height)
    )
    e % ("src" -> src)  // uses an implicit in Helpers from Tuple2 to MetaData
  }}


Note that if somehow "img" would match something other than an Elem, it would throw a MatchNotFoundError, so I'm relying on an assumption (which seems pretty sane); sometimes I wish the CSS selectors would be more type safe in this regard...

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