compilation - Is there a compiler preprocessor in Dart?

Question

Since a compilation is required before launching a dart application, i wonder if compiler preprocessor is available, or is scheduled in a near future for Dart.
My searches on the net / inside the dart site have proven unsuccessful so far.

( By preprocessor, i mean something like :

#define max(A,B)    ( (A) > (B) ? (A):(B)) 

or :

#define NumType double
#define NumTypeZero 0.0

// used with :
NumType myNum = NumTypeZero;

or :

#define DEBUG 

// use
#ifdef DEBUG
   print('var1 : $var1, var2:$var2, ...');
#endif

)

Edit : I wonder why there's not allready a pre-processor because it seems we are 'near' from that point :
- Dart has to scan the files for library dependencies to load the libraries in the right order.
- Dart editor also scan files for syntax, type checking and other checks.
- It's possible to have some automated file processing launched within the editor (i couldn't find a valuable link for this, please let me know if you have one).

Answer 1

Basically what the other guys said...

If you're compiling with dart2js, the tree-shaking will already throw out the code inside an if (DEBUG) {} block, if DEBUG is a constant and false. So you can just use if statements.

You can also use assert() statements. The assert, and the expression passed to it will be thrown away when compiling with dart2js for production mode.

So this is actually the same behaviour that you'd get with #ifdefs - you can think of dart2js as your preprocessor ;)

I also don't see any reason why you would want to use #defines instead of constants.

If you want to run your code in the DartVM, you can use dart2js --output-type=dart to do tree-shaking on your dart source.

Update: Also see String.fromEnvironment(), bool.fromEnvironment(), and int.fromEnvironment(). You can set these environment variables when compiling by using "dart2js -D<env-var-name>=<value>".