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digitalmars.D - D-issapointed after using C# for a while.

reply Taylor Hillegeist <taylorh140 gmail.com> writes:


suddenly realize the convenience and flexibility I had in D. One 
case in particular is with bit-fields in D they are a pleasure to 

Enums that are flexible for some cases, I suppose I just wanted 
to say thanks to the D community for their effort.
Nov 11 2016
parent reply Jerry <hurricane hereiam.com> writes:
On Friday, 11 November 2016 at 15:36:18 UTC, Taylor Hillegeist 
wrote:


 some other less popular languages. Most recently working with 

 D. One case in particular is with bit-fields in D they are a 

 sure they have Enums that are flexible for some cases, I 
 suppose I just wanted to say thanks to the D community for 
 their effort.


D doesn't have bitfields though? Phobos just has a template that 
emulates them by mixing in functions that do the bit shifting. 
Because it done through mixins it means you can't attach 
attributes to the fields. Which I am in need of. Haven't found a 
good workaround though.
Nov 11 2016
parent reply Jonathan M Davis via Digitalmars-d <digitalmars-d puremagic.com> writes:
On Friday, November 11, 2016 23:32:11 Jerry via Digitalmars-d wrote:

 D doesn't have bitfields though? Phobos just has a template that
 emulates them by mixing in functions that do the bit shifting.
 Because it done through mixins it means you can't attach
 attributes to the fields. Which I am in need of. Haven't found a
 good workaround though.


What attributes do you need that aren't there already? UDAs? Looking at the
code, the full set of appropriate built-in attributes are on them already.

- Jonathan M Davis
Nov 11 2016
parent reply Jerry <hurricane hereiam.com> writes:
On Saturday, 12 November 2016 at 01:02:05 UTC, Jonathan M Davis 
wrote:

 On Friday, November 11, 2016 23:32:11 Jerry via Digitalmars-d 
 wrote:

 D doesn't have bitfields though? Phobos just has a template 
 that emulates them by mixing in functions that do the bit 
 shifting. Because it done through mixins it means you can't 
 attach attributes to the fields. Which I am in need of. 
 Haven't found a good workaround though.


 What attributes do you need that aren't there already? UDAs? 
 Looking at the code, the full set of appropriate built-in 
 attributes are on them already.

 - Jonathan M Davis


Yah I need to associate some extra information with the bitfields 
using UDAs.
Nov 11 2016
parent reply Jonathan M Davis via Digitalmars-d <digitalmars-d puremagic.com> writes:
On Saturday, November 12, 2016 03:30:58 Jerry via Digitalmars-d wrote:

 On Saturday, 12 November 2016 at 01:02:05 UTC, Jonathan M Davis

 wrote:

 On Friday, November 11, 2016 23:32:11 Jerry via Digitalmars-d

 wrote:

 D doesn't have bitfields though? Phobos just has a template
 that emulates them by mixing in functions that do the bit
 shifting. Because it done through mixins it means you can't
 attach attributes to the fields. Which I am in need of.
 Haven't found a good workaround though.


 What attributes do you need that aren't there already? UDAs?
 Looking at the code, the full set of appropriate built-in
 attributes are on them already.

 - Jonathan M Davis


 Yah I need to associate some extra information with the bitfields
 using UDAs.


It would definitely be possible to make it so that std.bitmanip.bitfields
could handle UDAs, but I don't expect that it would be particularly fun to
implement. e.g. the example

struct A
{
    int a;
    mixin(bitfields!(
        uint, "x",    2,
        int,  "y",    3,
        uint, "z",    2,
        bool, "flag", 1));
}
A obj;
obj.x = 2;
obj.z = obj.x;

could become something like

struct A
{
    int a;
    mixin(bitfields!(
        uint, "x",    2, " Foo  Bar(12)"
        int,  "y",    3,
        uint, "z",    2, " Foo"
        bool, "flag", 1));
}
A obj;
obj.x = 2;
obj.z = obj.x;

but that would require making it so that bitfields looks at the types of
what it's passed to see if it has the extra string (similar to what
std.getopt.getopt does), and if it does, then it mixes in that string as
attributes on that field. It's a bit a of a pain to do, but it could be
done. What would make it worse though is if you want to try and make it so
that the attributes can be applied to just the setters or just the getters.
Then you'd probably end up with stuff like

struct A
{
    int a;
    mixin(bitfields!(
        uint, "x",    2, " Foo  Bar(12)", " Foo"
        int,  "y",    3,
        uint, "z",    2, " Foo", "",
        bool, "flag", 1));
}
A obj;
obj.x = 2;
obj.z = obj.x;

which is getting a bit ugly IMHO. But it would be possible.

In any case, that's the best approach that I can think of at the moment.

- Jonathan M Davis
Nov 11 2016
parent Era Scarecrow <rtcvb32 yahoo.com> writes:
On Saturday, 12 November 2016 at 03:59:08 UTC, Jonathan M Davis 
wrote:

 It would definitely be possible to make it so that 
 std.bitmanip.bitfields could handle UDAs, but I don't expect 
 that it would be particularly fun to implement. e.g. the example

 <Snip>

 which is getting a bit ugly IMHO. But it would be possible.

 In any case, that's the best approach that I can think of at 
 the moment.


  I can't help but remember that in my variant of Bitfields I had 
it allow default values. I could probably extract that part out 
and re-inject it into the current bitfields version, although I 
remember quite the fun time debugging said code, namely 
extracting the text generated...
Nov 12 2016