EDIT2
Scala IDE now has template support with type inference, semantic highlighting, etc. for the Play framework as of v3.0 of the IDE. Same deal with routes file(s), woohoo ;-)
Not sure about Play, Scalate, or other template engine support in IntelliJ.
EDIT
Play 2.0 is unbelievably awesome, so much so that the lack of IDE support is fairly minor -- all the heavy lifting is done via model, controller and javascript (coffeescript + datatables) layers; view layer consists of simple xhtml skeletons, so no biggie not having, for example, autocomplete for Scala code -- your app won't compile if there are errors regardless, so you're safe to boot ;-)
If and when template layer IDE support comes it will be a welcome addition, but nothing that I personally am losing any sleep over...
ORIGINAL
Just discovered something last night after a couple months of relative joy hacking around in Scala-IDE for Eclipse:
There appears to be NO template layer support whatsoever (code completion, syntax highlighting, etc.). This is the case even for TypeSafe's new adoptee, Play 2.0, with its Razor style @ syntax. Scalate, same boat, none of the uber cool options (jade, ssp, scaml) are detected by the IDE.
This is not just the case for Scala-IDE mind you, seems to be a given with IntelliJ as well, roughly 2 years after requesting template support: http://youtrack.jetbrains.com/issue/SCL-1876
Obviously, must be difficult to implement, otherwise we'd have built-in or plugin support for the main templating languages. Kind of groping in the dark here, the best I've been able to do is have the IDE interpret the .jade extension as Scala code, which highlights scala keywords in a pleasant light-blue and nothing else, no hovers, code completion, arrgggghhh ;-)
What are the alternatives here?? Coming from Groovy/Grails I have gotten spoiled by excellent IDE support for straight scala code and would dearly love to have that tied in with the template layer.
Play 2.0 support is planned for IntelliJ IDEA 12, some of Scala template languages are also planned for IntelliJ IDEA 12.
来源：https://stackoverflow.com/questions/9392924/scala-ide-intellij-template-support-for-scalate-play-etc