phobos dependencies

[H. S. Teoh]

On Thu, Dec 19, 2013 at 01:47:26AM +0400, Dmitry Olshansky wrote:
> 19-Dec-2013 01:40, Andrei Alexandrescu пишет:
> >On 12/18/13 1:16 PM, Dmitry Olshansky wrote:
> >>19-Dec-2013 01:06, Andrei Alexandrescu пишет:
> >>>http://chopapp.com/#fvepfd8 shows the number of dependencies (plus
> >>>1) for each module in phobos. Those include druntime dependencies.
> >>>
> >>
> >>So the bill of using pretty much anything in Phobos is pulling in 87
> >>modules. Pretty much what I feared it is.
> >
> >There are several directions we can take this.
> >
> >1. Improve the compiler to handle imports lazily, i.e. an unused
> >import is never opened. That's unlikely to help a lot of uses because
> >most unqualified name lookups require all imports to be loaded (even
> >after the name if resolved, the compiler must still look for
> >ambiguities).
> >
> >2. Push imports from top level into the entities (functions, classes
> >etc) that use them.
> >
> >3. Apply classic dependency management (break larger modules in
> >smaller ones, accept some code duplication etc).
> >
> >I favor (2).

I vote for (2) as well.

And for the first part of (3): I think std.algorithm is due for a
breakup. There is no reason why using find, for example, should pull in
sorting algorithms, and why using sorting algorithms should pull in
cartesianProduct.


> I'd add something that might help make (2) possible in case of
> templates.
> 
> 4. Split modules at least into a package of with at least 2 parts:
> - Meta (traits) - constraints, type definitions etc.
> - API - functions, globals and other "meat" of the module.
> 
> One prime example is std.range - isInputRange, isForwardRange etc.
> need not to be "bought together" with all of range adapters and
> std.algorithm dependency.
[...]

I've been saying this over and over: now we have package.d, let's make
use of it. Jonathan has been working on splitting up std.datetime
(though that has yet to materialize); I think std.algorithm and
std.range are due, too.


T

-- 
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