ANN: Scalatags 0.3.4

[Haoyi Li]

https://github.com/lihaoyi/scalatags

Lots of changes over the old 0.2.x series, even though 0.3.x was never really announced. Features include

• Although it was already pretty fast at 3-4x the speed of Play! templates, It's now even faster, with an estimated 20% speedup over the earlier version
• It now ships with two backends: scalatags.Text and Scalatags.JsDom, the latter only available on ScalaJS, but which allows really cool direct DOM manipulation that is impossible when it only spewed out text. New possibilities include directly binding onXXX handlers in a Scalatags fragment, functional-reactive programming and other things!

There are also lots of changes to the internals:

• The new ASTs, unlike the old ones, are now more-or-less opaque and can't be easily transformed by walking over them.
• In exchange, 0.3.x has new typeclass-based extension points that are well defined, serving as places where you can hook custom logic into Scalatag and somewhat substituting the use-case of tree-transformers
• A completely re-done architecture, to support the new dual-backend setup, opening the door to the possibility of writing code that targets both the Text and JsDom backends at the same time
• Basically all the internal data structures have been renamed (documented here), and make much more sense than they did in 0.2.x

I welcome any questions/opinions/feedback =)

[Haoyi Li]

> I was wondering if you had given more though to SVG support, I know there is this pull request pending

I haven't; I did most of this on the plane back from Berlin, and only arrived in San Francisco <24hrs ago. Will look at your PR in due course =)

On Sun, Jun 22, 2014 at 2:41 PM, Benjamin Jackman <benjamin...@gmail.com> wrote:

Looks really good! I have been using it all day and having static typing is really nice!

I was wondering if you had given more though to SVG support, I know there is this pull request pending:

https://github.com/lihaoyi/scalatags/pull/22

I was thinking about replacing some d3 charts with a scalatags version to see if it produces more elegent code 

I want to wait until svg is ready.

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[Haoyi Li]

Currently, not really. I used to have that feature, but it got lost in the 0.3.x rewrite, and I didn't feel strongly enough to put it back in. If it's important to you, you could try implementing it (would mostly involve fiddling around here and here, moving/aliasing things inside the StringTags mixin) and send a PR. 

It would probably take some work to make it compile with all the newly path-dependent types, which is why I haven't done it. I'm already doing pretty crazy type/trait stuff and it's amazing that it compile at all as is =P

On Mon, Jun 23, 2014 at 10:41 PM, Benjamin Jackman <benjamin...@gmail.com> wrote:

Is there a way to shorten this in my own library

    import scalatags.JsDom._

    import scalatags.JsDom.tags._

    import scalatags.JsDom.{styles => s, attrs => a}

so that I only have to do one import aka something like:

import cgta.ScalatagsStyle._

[Haoyi Li]

@BenjaminJackman I've published 0.3.8, which reduces the imports required to a single import and allows you to define custom bundles which can also provide whatever import conventions you desire with a single-import (see the unit test)

It's a pretty big re-organization and may have issues I haven't bumped into, so let me know if there are any problems. It works well enough for the unit tests and scala-js-fiddle in any case. Try it out =)

[Benjamin Jackman]

Wow awesome Thanks you so much! Looking forward to trying it out!

[Benjamin Jackman]

Ok trying it out now, 

    import scalatags.JsDom.{styles => s, attrs => a, _}

    import scalatags.JsDom.tags._

    println("Hello World Main Called")

    val t = div(s.color := "red")("SCALA JS APPEARS TO WORK!").render

    val b = button(a.onclick := (() => t.textContent = s"Clicked ${i += 1; i} times"))("Click Me").render

is giving me errors:

[error] /home/bjackman/cgta/orange/viz-sjs/src/main/scala/cgta/viz/learn/OjsHelloWorld.scala:20: could not find implicit value for parameter ev: scalatags.generic.StyleValue[Builder,String]

[error]     val t = div(s.color := "red")("SCALA JS APPEARS TO WORK!").render

[error]                         ^

[error] /home/bjackman/cgta/orange/viz-sjs/src/main/scala/cgta/viz/learn/OjsHelloWorld.scala:21: could not find implicit value for parameter ev: scalatags.generic.AttrValue[Builder,() => <error>]

[error]     val b = button(a.onclick := (() => t.textContent = s"Clicked ${i += 1; i} times"))("Click Me").render

[error]        

    import scalatags.JsDom.all._

works, if I remove the s. and a.

    import scalatags.JsDom.tags._

    import scalatags.JsDom.short._

also works.

Will try custom bundles next

[Haoyi Li]

If you're not using all or short, you need to pull in the implicits via import scalatags.JsDom.implicits._ If you make a custom bundle that mixes in Aggregate and import from it, that will provide the implicits too.

[Benjamin Jackman]

gotcha ok makes sense

[Benjamin Jackman]

So this is what i ended up going with for the JsDom Bundle:

import scalatags.{JsDom, jsdom}

object OTags extends JsDom.Cap with jsdom.Tags with JsDom.Aggregate with scalatags.LowPriorityImplicits {

  object S extends JsDom.Cap with JsDom.Styles

  object A extends JsDom.Cap with JsDom.Attrs

}

    import OTags._

    val t = div(S.color := "red")("SCALA JS APPEARS TO WORK!").render

    val b = button(A.onclick := (() => t.textContent = s"Clicked ${i += 1; i} times"))("Click Me").render

Seems to work great!

Thanks so much!