How to avoid recompiling on changes in *.scala.html files - scala

I am using play framework v2.3. The problem I am facing is that any change in html and refreshing browser causes recompilation of the complete code. Can I avoid this?

Twirl templates are compiled, as stated by the docs:
Templates are compiled as standard Scala functions, following a simple naming convention. If you create a views/Application/index.scala.html template file, it will generate a views.html.Application.index class that has an apply() method.
There is no way to disable this behavior because it works this way by design. My suggestion here is use ~ (tilde) before SBT commands so things will happen as you save the file, per instance:
sbt ~run
This will recompile the changed file (and possible others), every time you change and save it. Also, sbt has some options that can possibly help you here: withNameHashing.
See sbt docs to understand how it works. To enable it, add the following line to your build.sbt file:
incOptions := incOptions.value.withNameHashing(nameHashing = true)

Related

Generate xml files during sbt build

I would like to generate xml files during sbt build based on higher level config(lets say yaml), then package them into the tar file(by sbt-native-packager). What would be the simplest way to achieve that?
One way I can think of is to add twirl to project/build.sbt and than use it to write custom task. Is there some simpler way to do that?
To use twirl, you would need to add twirl as a plugin to the your projects builds build - it's a bit meta, the location of your twirl files will be a bit unintuitive (projcet/src/main/twirl). I've done it, but in my opinion it's just not worth it for most use cases.
I would instead just use scala-xml. If using sbt 0.13 (ie, Scala 2.10), then you can just embed the xml directly in your Scala code, otherwise for sbt 1.0 you may need to add a dependency on scala-xml in your project/plugins.sbt (though possibly sbt 1.0 already depends on scala-xml, not sure).
Here's an example of a task that generates XML:
https://github.com/lagom/lagom/blob/4a75ab0773b2cc3f55b6c5fae3f96ba08ddcf4c0/project/SbtMavenPlugin.scala#L47
Scroll down to see examples of embedding xml in Scala:
https://github.com/lagom/lagom/blob/4a75ab0773b2cc3f55b6c5fae3f96ba08ddcf4c0/project/SbtMavenPlugin.scala#L158-L162

Turn off Scala lint warnings at a less-than-global scope?

I'd like to be able to turn off a particular compiler warning, but only for a single file in my project. Is this possible?
The context is that I have a single source file that makes calls to an external macro library that produces adapted-arg warnings. I found that I can eliminate these warnings by changing my build.sbt file:
scalacOptions ++= Seq("-Xlint:-adapted-args,_" /*, ... */)
However, this turns off the warning globally, and I only want it off for the single file that raises them.
I haven't had any luck searching for any of the following possible solutions I thought might exist:
Specifying separate compilation options for different files in my project in my build.sbt file
Providing some pragma-like comment in my source file to change the warnings generated by the compiler, similar to the special scalastyle:on/off comments recognized by Scalastyle
Some annotation for smaller regions of code, like #unchecked
So, is there any way to have different linting options in effect for different files, or even for limited regions of code?
The expectation was that folks would write a custom Reporter that would filter out undesirable warnings.
It's easy to write one that filters by file name, perhaps given a whitelist.
The error/warn API supplies the textual Position. It would also be easy to parse the position.lineContent for a magic comment token like IGNORE or SUPPRESS, which is not as convenient as a SuppressWarnings annotation but is easy to implement.
The compiler asks the reporter if there were errors.
The custom reporter is specified with -Xreporter myclass, or it wouldn't surprise me if someone has written an sbt plugin.

Fay: include another Fay file?

I have one Fay file which is the heart of my program, however I need some helpers for my logic, for instance a method to replace substrings. From what I understand, if I need such methods which are offered by many Haskell libraries from Hackage directly, I can't use those Haskell libraries, but I must copy-paste the code in my project. So it's what I did, I copy-pasted a "replace" function together with other helpers from the MissingH library in a new file in my project: Utils.hs.
That Utils.hs compiles without problems with Fay. Also I import it in my main Fay file and I get a JS file for the main project file without problems. However at runtime I get the following error:
ReferenceError: Utils$$36$ is not defined
I don't think that Fay will include the code from the helper file in my main JS file, so I'm including both JS files in the loading HTML. And to make even more sure that when I load the main file, that the utils file is loaded, I load it like that:
$.getScript("Utils.js", function(){
$.getScript("FayConfig.js");
});
But despite this I still get the error. I tried compiling the Utils.hs with "--library" but it didn't help.
So my question is, which setup do I need to achieve that the generated JS will find the helper functions that I put in another HS file, knowing that at compile-time, Fay (apparently) finds them without problems? Is there an example of such a setup online? Most of the Fay uses that I found have all the code in a single HS file, though they often use external Fay code from cabal, as with fay-jquery. In my case, setting up a cabal project just for these simple helpers would be overkill.
Which version of Fay are you using (fay --version)? It seems like you are using a version older than
0.16 where forgetting import Prelude wouldn't give any warnings, see this closed ticket. So upgrade fay and/or add import Prelude.
We're also considering renaming operators in the produced output to make error messages like these easier to understand.
You do not need to invoke fay several times, fay outputs all dependencies into the same js file. So there's no difference from using a cabal package in that regard.
Hope this helps, otherwise please give me a way to reproduce this.

Gwt i18n > generating properties files

I'm using GWT in my stuff, and I would like to make it,
international, so I use GWT constants method.
I have a java file with defaults, and I now need to make properties files.
In a remember, there is a special thing to do (or done automagically) to generate
a kind of template where all constants are generated with empty labels for other langages.
Did I dream this ?
(using eclipse indigo to develop webapp with gwt but not gae)
[edit:]
this was not a dream, it's i18ncreator:
http://code.google.com/intl/fr-FR/webtoolkit/doc/latest/RefCommandLineTools.html#i18nCreator
but I can't make it working on windows :-(
[edit again ]
due to this issue : http://code.google.com/p/google-web-toolkit/issues/detail?id=5113
recommended solution is use i18ncreator in gwt 1.7 (!)
you should see the page on locales in GWT
I had the same issue. I was looking all over the place for the answer but could not find an answer; either in the docs or on stackoverflow.
So I asked in the GWT gitter channel and was told to use the compiler argument
-extra <destination-folder-name>
to generate the .properties files from the Interface files.
Steps in eclipse:
Select project you want to compile
[right click] -> Google -> GWT Compile
In the window that opens, open the Advanded options.
Add the following additional compiler argument -extra <destination-folder-name>
Compile
This should generate the *.properties files in the /destination-folder-name.
NOTE: This only generates the .properties files. It does not actually compile the application with all the locales for deploy.
Move the MyInterfaceExtension_*.properties to be right beside the MyInterfaceExtension.java file.
Make copies for each locale i.e. MyInterfaceExtension_fr_CA.properties, MyInterfaceExtension_fr_FR.properties, etc..
Translate them
Then run the compilation process again with out the -extra <destination-folder-name> option. Because it is not needed anymore.
This will compile with all the locales you enabled. You can now deploy the app the usual way.
Quick Tips:
When compiling for the first time in order to generate the .properties file, I commented out the locales in the module definition file so that the compiler will not sit there and compile again and again for every browser and every locale
i.e. supported_browser_count x enabled_locale_count = 5 browsers x 3 locales = 15 compilation Permutations, which is going to increase your compilation time.
Because, all I needed was that one *_en.properties file.
For the second compilation, after you copied and translated the properties files for each locale, you have to enable all the locales you want to support and compile.
Credits:
github #niloc132 : Colin Alworth
github #ibaca : Ignacio Baca Moreno-Torres
For helping me with this.
For my project, I used the i18n-Creator
http://code.google.com/webtoolkit/doc/latest/DevGuideI18n.html#DevGuidePropertiesFiles
It kind of does the opposite of what you are asking for. With the i18n-creator, you create the properties files for the various locales and run the script that is generated with the i18n-creator, and it will generate the constants interface.
I haven't heard yet of this feature in Eclipse but IntelliJ IDEA has this feature, you just create the Constants Interface class and the properties file. If you add a method in the class file it will warn you to add the property or the other way around. HTH.

Error with Groovy AST transformations when cleaning project in Eclipse

I'm trying to work through groovy's Implementing Local AST Transformations tutorial, but whenever I clean my project I get this error in each file that has the #WithLogging annotation in it:
Groovy:Could not find class for Transformation Processor AC.LoggingASTTransformation declared by AC.WithLogging
So you have a package named "AC" that contains both "WithLogging.groovy" and "LoggingASTTransformation.groovy" classes? Does it also contain any classes that implement the "WithLogging" interface?
If so, I'd suggest you move the class(es) that use your annotation to a location outside of the annotation defining package (the default will suffice, for diagnostic purposes) - Order of compilation matters with transformations. See this post on the groovy users mailing list for more on that.
Also try changing the annotation from #WithLogging to #AC.WithLogging.
As far as cleaning with Eclipse is concerned, I had a similar issue and found that I had to make a trivial modification after a clean to any file that contained my annotation. IE, add a space somewhere. Then save the file. This should rebuild everything properly.