Please integrate build framework into the compiler

[grauzone]

I don't really understand what you mean. But if you want the compiler to 
scan for dependencies, I fully agree.

I claim that we don't even need incremental compilation. It would be 
better if the compiler would scan for dependencies, and if a source file 
has changed, recompile the whole project in one go. This would be simple 
and efficient.

Here are some arguments that speak for this approach:

- A full compiler is the only piece of software that can build a 
correct/complete module dependency graph. This is because you need full 
semantic analysis to catch all import statements. For example, you can 
use a string mixin to generate import statements: mixin("import bla;"). 
No naive dependency scanner would be able to detect this import. You 
need CTFE capabilities, which require almost a full compiler. (Actually, 
dsss uses the dmd frontend for dependency scanning.)

- Speed. Incremental compilation is godawfully slow (10 times slower 
than to compile all files in one dmd invocation). You could pass all 
changed files to dmd at once, but this is broken and often causes linker 
errors (ask the dsss author for details lol). Recompiling the whole 
thing every time is faster.

- Long dependency chains. Unlike in C/C++, you can't separate a module 
into interface and implementation. Compared to C++, it's as if a change 
to one .c file triggers recompilation of a _lot_ of other .c files. This 
makes incremental compilation really look useless. Unless you move 
modules into libraries and use them through .di files.

I would even go so far to say, that dmd should automatically follow all 
imports and compile them in one go. This would be faster than having a 
separate responsefile step, because the source code needs to be analyzed 
only once. To prevent compilation of imported library headers, the 
compiler could provide a new include switch for library code. Modules 
inside "library" include paths wouldn't be compiled.

Hell, maybe I'll even manage to come up with a compiler patch, to turn 
this into reality.