[Scons-users] Scala-Support

[Russel Winder]

On Mon, 2012-09-03 at 21:47 +0000, Kenny, Jason L wrote:

> So what can handle it?


Gradle, possible Maven but… 

Many will say Ant, but I think they need to rethink their position!


> I read what you said... and it makes me think that nothing could

> handle this. One is always stuck always building all sources and

> hoping the compiler can deal with optimizing what is done, as there is

> not a way without compiling the sources in some way to get what it

> will output.


Only if you have a single phase of DAG building. Having multiphase
approach seems to work really well.  I have yet to find a case where
Gradle performs unnecessary compilation of Java, Scala, or Groovy files.

Although Gradle is trying to develop a C++ build capability, it is not
yet in a fit state and I am not sure it will ever get close to SCons
(and Waf) without addition of C++ addicts to the development team.  And
Gradle just cannot handle LaTeX, D, Fortran, etc. 


> This suggests to me that a Java scanner would need to compile the

> source in some way and parse the out of something to return what

> depends on what. Or better set it seems that to do Java you need the

> emitter to do this, and cache the value based on the MD5 of the source

> file. So if the java file MD5 changed the emitter would have to

> re-"compile" the source files to see what it would output.


It is definitely the case that you have to compile Java and Scala code
to ascertain the compilation products. I suspect your strategy might
work but you end up having to replicate the basic SCons core in the
emitter so as to effectively, create a multiphase approach: first DAG
build, first compilation try, DAG patch, redundant recompilation.

-- 
Russel.
=============================================================================
Dr Russel Winder      t: +44 20 7585 2200   voip: sip:russel.winder at ekiga.net
41 Buckmaster Road    m: +44 7770 465 077   xmpp: russel at winder.org.uk
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