Re: Capture parameter identifier name in a template?
I have just checked it and yes, it works with a constant that is not an
enum: `const int FOO` defined in the module namespace or `static int
BAR` defined in the dummy Vm class.
On 08/14/2014 02:08 PM, Maxime Chevalier-Boisvert wrote:
> Thanks. Does it also work with a constant that's not an enum, e.g.:
const int FOO?
>
> On 08/14/2014 01:23 PM, Rémy Mouëza wrote:
>> Using __traits (identifier, ...) and a template alias seems to work
for me:
>>
>> import std.stdio;
>>
>> /// Two kinds of enums:
>>
>> /// A named enum.
>> enum VmParams {
>> OBJ_MIN_CAP,
>> PROTO_SLOT_IDX,
>> FPTR_SLOT_IDX,
>> }
>>
>> /// An anonymous one.
>> enum {
>> ATTR_CONFIGURABLE = 3,
>> ATTR_WRITABLE,
>> ATTR_ENUMERABLE,
>> ATTR_DELETED,
>> ATTR_GETSET,
>> ATTR_DEFAULT
>> }
>>
>> /// A dummy Vm class for example purpose.
>> class Vm {
>> /// Stores values.
>> int [string] table;
>>
>> /// The "classic" runtime const API.
>> void defRTConst (string id, int val) {
>> table [id] = val;
>> }
>>
>> /// Using an alias with the identifier trait.
>> void rtConst (alias p) () {
>> table [__traits (identifier, p)] = p;
>> }
>>
>> /// Initializes our .table member.
>> this () {
>> /// Using the allMembers traits we can process all the members
>> of a
>> /// named enum.
>> foreach (member; __traits (allMembers, VmParams)) {
>> int value = mixin ("VmParams." ~ member);
>> this.defRTConst (member, value);
>> }
>>
>> /// Without duplicating the name and its value.
>> rtConst!ATTR_CONFIGURABLE;
>> rtConst!ATTR_WRITABLE;
>> rtConst!ATTR_ENUMERABLE;
>> rtConst!ATTR_DELETED;
>> rtConst!ATTR_GETSET;
>> rtConst!ATTR_DEFAULT;
>>
>> /* rtConst won't work with local variables:
>> // auto foo = ATTR_DEFAULT;
>> // rtConst!foo;
>> The code above raises a compiler error:
>> Error: template instance rtConst!(foo) cannot use local
>> 'foo' as parameter to non-global template rtConst(alias p)()
>> */
>> }
>> }
>>
>> void main () {
>> Vm vm = new Vm;
>> vm.table.writeln;
>>
>> /// output:
>> /// ["OBJ_MIN_CAP":0, "ATTR_WRITABLE":4, "ATTR_ENUMERABLE":5,
>> "ATTR_GETSET":7, "PROTO_SLOT_IDX":1, "FPTR_SLOT_IDX":2,
>> "ATTR_CONFIGURABLE":3, "ATTR_DELETED":6, "ATTR_DEFAULT":8]
>> }
>>
>>
>> On 08/12/2014 07:36 PM, Maxime Chevalier-Boisvert wrote:
>>> In my JavaScript VM, I have a function whose purpose is to expose
D/host
>>> constants to the JavaScript runtime code running inside the VM. This
>>> makes for somewhat redundant code, as follows:
>>>
>>> vm.defRTConst("OBJ_MIN_CAP"w, OBJ_MIN_CAP);
>>> vm.defRTConst("PROTO_SLOT_IDX"w, PROTO_SLOT_IDX);
>>> vm.defRTConst("FPTR_SLOT_IDX"w, FPTR_SLOT_IDX);
>>> vm.defRTConst("ATTR_CONFIGURABLE"w , ATTR_CONFIGURABLE);
>>> vm.defRTConst("ATTR_WRITABLE"w , ATTR_WRITABLE);
>>> vm.defRTConst("ATTR_ENUMERABLE"w, ATTR_ENUMERABLE);
>>> vm.defRTConst("ATTR_DELETED"w , ATTR_DELETED);
>>> vm.defRTConst("ATTR_GETSET"w, ATTR_GETSET);
>>> vm.defRTConst("ATTR_DEFAULT"w , ATTR_DEFAULT);
>>>
>>> I'm just wondering if there's a way to template defRTConst so that the
>>> name of an identifier I'm passing (e.g.: ATTR_DEFAULT) can be captured
>>> by the template, making it so that I don't also need to pass the
name as
>>> a string. I expect the answer to be no, but maybe someone with more
>>> knowledge of D template magic knows better.
>>
Re: Capture parameter identifier name in a template?
Using __traits (identifier, ...) and a template alias seems to work for me:
import std.stdio;
/// Two kinds of enums:
/// A named enum.
enum VmParams {
OBJ_MIN_CAP,
PROTO_SLOT_IDX,
FPTR_SLOT_IDX,
}
/// An anonymous one.
enum {
ATTR_CONFIGURABLE = 3,
ATTR_WRITABLE,
ATTR_ENUMERABLE,
ATTR_DELETED,
ATTR_GETSET,
ATTR_DEFAULT
}
/// A dummy Vm class for example purpose.
class Vm {
/// Stores values.
int [string] table;
/// The "classic" runtime const API.
void defRTConst (string id, int val) {
table [id] = val;
}
/// Using an alias with the identifier trait.
void rtConst (alias p) () {
table [__traits (identifier, p)] = p;
}
/// Initializes our .table member.
this () {
/// Using the allMembers traits we can process all the members
of a
/// named enum.
foreach (member; __traits (allMembers, VmParams)) {
int value = mixin ("VmParams." ~ member);
this.defRTConst (member, value);
}
/// Without duplicating the name and its value.
rtConst!ATTR_CONFIGURABLE;
rtConst!ATTR_WRITABLE;
rtConst!ATTR_ENUMERABLE;
rtConst!ATTR_DELETED;
rtConst!ATTR_GETSET;
rtConst!ATTR_DEFAULT;
/* rtConst won't work with local variables:
// auto foo = ATTR_DEFAULT;
// rtConst!foo;
The code above raises a compiler error:
Error: template instance rtConst!(foo) cannot use local
'foo' as parameter to non-global template rtConst(alias p)()
*/
}
}
void main () {
Vm vm = new Vm;
vm.table.writeln;
/// output:
/// ["OBJ_MIN_CAP":0, "ATTR_WRITABLE":4, "ATTR_ENUMERABLE":5,
"ATTR_GETSET":7, "PROTO_SLOT_IDX":1, "FPTR_SLOT_IDX":2,
"ATTR_CONFIGURABLE":3, "ATTR_DELETED":6, "ATTR_DEFAULT":8]
}
On 08/12/2014 07:36 PM, Maxime Chevalier-Boisvert wrote:
In my JavaScript VM, I have a function whose purpose is to expose D/host
constants to the JavaScript runtime code running inside the VM. This
makes for somewhat redundant code, as follows:
vm.defRTConst("OBJ_MIN_CAP"w, OBJ_MIN_CAP);
vm.defRTConst("PROTO_SLOT_IDX"w, PROTO_SLOT_IDX);
vm.defRTConst("FPTR_SLOT_IDX"w, FPTR_SLOT_IDX);
vm.defRTConst("ATTR_CONFIGURABLE"w , ATTR_CONFIGURABLE);
vm.defRTConst("ATTR_WRITABLE"w , ATTR_WRITABLE);
vm.defRTConst("ATTR_ENUMERABLE"w, ATTR_ENUMERABLE);
vm.defRTConst("ATTR_DELETED"w , ATTR_DELETED);
vm.defRTConst("ATTR_GETSET"w, ATTR_GETSET);
vm.defRTConst("ATTR_DEFAULT"w , ATTR_DEFAULT);
I'm just wondering if there's a way to template defRTConst so that the
name of an identifier I'm passing (e.g.: ATTR_DEFAULT) can be captured
by the template, making it so that I don't also need to pass the name as
a string. I expect the answer to be no, but maybe someone with more
knowledge of D template magic knows better.
Re: Capture parameter identifier name in a template?
On Tuesday, 12 August 2014 at 17:36:41 UTC, Maxime
Chevalier-Boisvert wrote:
In my JavaScript VM, I have a function whose purpose is to
expose D/host constants to the JavaScript runtime code running
inside the VM. This makes for somewhat redundant code, as
follows:
vm.defRTConst("OBJ_MIN_CAP"w, OBJ_MIN_CAP);
vm.defRTConst("PROTO_SLOT_IDX"w, PROTO_SLOT_IDX);
vm.defRTConst("FPTR_SLOT_IDX"w, FPTR_SLOT_IDX);
vm.defRTConst("ATTR_CONFIGURABLE"w , ATTR_CONFIGURABLE);
vm.defRTConst("ATTR_WRITABLE"w , ATTR_WRITABLE);
vm.defRTConst("ATTR_ENUMERABLE"w, ATTR_ENUMERABLE);
vm.defRTConst("ATTR_DELETED"w , ATTR_DELETED);
vm.defRTConst("ATTR_GETSET"w, ATTR_GETSET);
vm.defRTConst("ATTR_DEFAULT"w , ATTR_DEFAULT);
I'm just wondering if there's a way to template defRTConst so
that the name of an identifier I'm passing (e.g.: ATTR_DEFAULT)
can be captured by the template, making it so that I don't also
need to pass the name as a string. I expect the answer to be
no, but maybe someone with more knowledge of D template magic
knows better.
Something like this?
enum ATTRS
{
ATTR_GETSET,
ATTR_ENUMERABLE,
ATTR_CONFIGURABLE
}
void foo(ATTRS attr)
{
import std.conv;
foo_impl(attr, to!string(attr));
}
void foo_impl(ATTRS attr, string name)
{
import std.stdio;
writefln("name = %s, attr = %d", name, attr);
}
void main()
{
foo(ATTRS.ATTR_GETSET);
}
Re: Capture parameter identifier name in a template?
On Tue, Aug 12, 2014 at 05:36:40PM +, Maxime Chevalier-Boisvert via
Digitalmars-d-learn wrote:
> In my JavaScript VM, I have a function whose purpose is to expose
> D/host constants to the JavaScript runtime code running inside the VM.
> This makes for somewhat redundant code, as follows:
>
> vm.defRTConst("OBJ_MIN_CAP"w, OBJ_MIN_CAP);
> vm.defRTConst("PROTO_SLOT_IDX"w, PROTO_SLOT_IDX);
> vm.defRTConst("FPTR_SLOT_IDX"w, FPTR_SLOT_IDX);
> vm.defRTConst("ATTR_CONFIGURABLE"w , ATTR_CONFIGURABLE);
> vm.defRTConst("ATTR_WRITABLE"w , ATTR_WRITABLE);
> vm.defRTConst("ATTR_ENUMERABLE"w, ATTR_ENUMERABLE);
> vm.defRTConst("ATTR_DELETED"w , ATTR_DELETED);
> vm.defRTConst("ATTR_GETSET"w, ATTR_GETSET);
> vm.defRTConst("ATTR_DEFAULT"w , ATTR_DEFAULT);
>
> I'm just wondering if there's a way to template defRTConst so that the
> name of an identifier I'm passing (e.g.: ATTR_DEFAULT) can be captured
> by the template, making it so that I don't also need to pass the name
> as a string. I expect the answer to be no, but maybe someone with
> more knowledge of D template magic knows better.
I know it's possible to get function (runtime) parameter names using
__traits(), but I'm not sure if that can be done for compile-time
parameters. See: std.traits.ParameterIdentifierTuple.
T
--
It said to install Windows 2000 or better, so I installed Linux instead.
Re: Capture parameter identifier name in a template?
On Tue, 12 Aug 2014 17:36:40 + Maxime Chevalier-Boisvert via Digitalmars-d-learn wrote: > I'm just wondering if there's a way to template defRTConst so > that the name of an identifier I'm passing (e.g.: ATTR_DEFAULT) seems that this is the work for mixins. signature.asc Description: PGP signature
Capture parameter identifier name in a template?
In my JavaScript VM, I have a function whose purpose is to expose
D/host constants to the JavaScript runtime code running inside
the VM. This makes for somewhat redundant code, as follows:
vm.defRTConst("OBJ_MIN_CAP"w, OBJ_MIN_CAP);
vm.defRTConst("PROTO_SLOT_IDX"w, PROTO_SLOT_IDX);
vm.defRTConst("FPTR_SLOT_IDX"w, FPTR_SLOT_IDX);
vm.defRTConst("ATTR_CONFIGURABLE"w , ATTR_CONFIGURABLE);
vm.defRTConst("ATTR_WRITABLE"w , ATTR_WRITABLE);
vm.defRTConst("ATTR_ENUMERABLE"w, ATTR_ENUMERABLE);
vm.defRTConst("ATTR_DELETED"w , ATTR_DELETED);
vm.defRTConst("ATTR_GETSET"w, ATTR_GETSET);
vm.defRTConst("ATTR_DEFAULT"w , ATTR_DEFAULT);
I'm just wondering if there's a way to template defRTConst so
that the name of an identifier I'm passing (e.g.: ATTR_DEFAULT)
can be captured by the template, making it so that I don't also
need to pass the name as a string. I expect the answer to be no,
but maybe someone with more knowledge of D template magic knows
better.
