Dependency management in D

[Vladimir Panteleev via Digitalmars-d]

On Thursday, 18 September 2014 at 16:48:22 UTC, Scott Wilson 
wrote:
> Unit of compilation is one D file but I saw if I pass several D
> files to the compiler only one .o file is generated. Whats the
> story there.

DMD will generate one object file per module file, unless you use 
the -of option. With -of, the compiler will compile all module 
files to a single object file.

> Plus if I change a non template function in one module then
> theres no way to tell make no rebuild of modules importing it.
> The dmd -deps call seems to generate all recursively. In
> gcc/makedepend if one function changes only relinking is needed
> or nothing if dynamic loading.

Yes, currently any changes, including function bodies, cause a 
rebuild of importing modules. One reason for this is CTFE - 
changing a function body can affect the code in importing modules 
if they invoke the function during compilation. You could use .di 
files to separate declarations from implementations.

> Overall as far as I understand compiler is fast but dependency
> mgmt is coarse. Also whats the deal with cyclic dependencies. I
> saw discussion that its not possible but wrote a few test 
> modules
> and it works fine.

Cyclic dependencies between modules which all have module or 
static constructors are forbidden, because it is unknown in which 
order the constructors are expected to run.