DMD 1.038 and 2.022 releases

[John Reimer]

Hello Nick,

> "John Reimer" <terminal.node at gmail.com> wrote in message
> news:28b70f8cfcfe8cb30c0a0e2ac70 at news.digitalmars.com...
> 
>> Hello Sean,
>> 
>>> bearophile wrote:
>>> 
>>>> Walter Bright:
>>>> 
>>>>> Excess isn't the problem, I want to see if import cycles is.
>>>>> 
>>>> Generally all the modules in my dlibs import each other. This is
>>>> nearly unavoidable, if a module contains string functions, and
>>>> another one contains math stuff, the string module will want to use
>>>> some math stuff and the math module may need string representations
>>>> and processing. In the D specs I haven't seen an advice to not use
>>>> cyclic imports, so I don't want such compiler flag, I prefer a
>>>> compiler able to manage such cyclic imports efficiently.
>>>> 
>>> Cyclic imports are a bad idea in general because of the impact they
>>> have on verifiability (unit testing).  But as you say, sometimes
>>> they're unavoidable.
>>> 
>>> Sean
>>> 
>> I'd going to wager that they are /often/ unavoidable, especially in
>> ported projects from other languages that have either no concept or a
>> different concept of modules/packages.
>> 
>> DWT is perhaps the single worse example of cyclic imports.  I'm not
>> sure
>> how the design could have been improved in Java's SWT.  All it takes
>> is
>> the need to reference one symbol in each module (because each object
>> apparently needs to just "know" about the other) to create a cyclic
>> import
>> issue in D.
>> Static initialization has also been a problem in DWT such that a few
>> significant workarounds were necessary.
>> I agree that the interdepencies should be avoided in all new projects
>> designed specifically for D.  I'm just not sure what the solution
>> would be for the great mass of ported software.
>> 
>> -JJR
>> 
> This might be a naive idea, and wouldn't solve the problems with
> cyclic dependancies in the general case: But regarding the static
> initializaton issue (which I've come up against myself), what if
> static initializers allowed some sort of clause like this:
> 
> module foo;
> import bar;
> // Exact syntax not really important right now
> this() dependsOn(bar) {
> // Do some initing that depends on
> // bar's static initializer having been run.
> }
> That would force foo's static initialization to be run sometime after
> bar's. Obviously, any cycles in the graph of "dependsOn"s would be an
> error.
> 

Some sort of explicit ordering would likely be a solution.  It would be /really/ 
nice if their were a clean way of implementing this... but it's really hard 
to say how it should be done.  I'm not sure how it is done (if at all) in 
other languages that implement a similar feature.

All I know is that, static initializations become almost useless at worst 
and extremely problematic at best in large projects, especially object based 
ones.  There are workarounds, of course.  One ends up having to learn not 
to be too dependent on this D feature.

-JJR