Re: local class instance (at module-level)
On 15/03/2019 00:45, ag0aep6g via Digitalmars-d-learn wrote:
On 14.03.19 20:43, Jacob Carlborg wrote:
class C {
uint i ;
this (uint i) {
this.i = i ;
}
this (uint i) shared {
this.i = i ;
}
this (uint i) immutable {
this.i = i ;
}
}
__gshared c0 = new C(0);
shared c1 = new shared C(1);
immutable c2 = new immutable C(2);
You only need one of the constructors depending on if you want a __gshared,
shared or immutable variable.
If you make it `pure`, you can use the same constructor in all cases:
class C {
uint i ;
this (uint i) pure {
this.i = i ;
}
}
__gshared c0 = new C(0);
shared c1 = new shared C(1);
immutable c2 = new immutable C(2);
all right, thank you!
Re: local class instance (at module-level)
On 14.03.19 20:43, Jacob Carlborg wrote:
class C {
uint i ;
this (uint i) {
this.i = i ;
}
this (uint i) shared {
this.i = i ;
}
this (uint i) immutable {
this.i = i ;
}
}
__gshared c0 = new C(0);
shared c1 = new shared C(1);
immutable c2 = new immutable C(2);
You only need one of the constructors depending on if you want a
__gshared, shared or immutable variable.
If you make it `pure`, you can use the same constructor in all cases:
class C {
uint i ;
this (uint i) pure {
this.i = i ;
}
}
__gshared c0 = new C(0);
shared c1 = new shared C(1);
immutable c2 = new immutable C(2);
Re: local class instance (at module-level)
On 2019-03-14 12:05, spir wrote:
I desperately try to declare/define/initialise a simple class instance
at module-level. This is a special (conceptually static and immutable)
instance used as a "marker", that just should exist and be accessible by
methods of this class and/or other classes defined in the same module.
(Thus I don't care if TLS.) I use it as a remplacement for null, to
avoid semantic confusion and unhelpful segfaults in case of bug.
I have tried a number of options and never manage to do it, including:
* [C/auto/static immutable c0] = new C(0) ;
* C c0 ; c0.i = 0 ;
* defining a static this()
* more...
The most confusing error is:
Error: variable `_base.c0` is a thread-local class and cannot have a
static initializer. Use `static this()` to initialize instead.
I also could not find any information --for a while, repeatedly, since I
can go on developing in the meantime, using null instead. I'm bluffed
and confused, since there is nothing weird in that, is there? (the
compiler can just allocate it in static mem and take the address)
Reduced test case:
===
class C {
uint i ;
this (uint i) {
this.i = i ;
}
}
// error
auto c0 = new C(0) ;
void main () {
// ok
auto c0 = new C(0) ;
}
===
I would enjoy an explanation (or a pointer to) in addition to a solution.
It works if it's not a TLS variable:
class C {
uint i ;
this (uint i) {
this.i = i ;
}
this (uint i) shared {
this.i = i ;
}
this (uint i) immutable {
this.i = i ;
}
}
__gshared c0 = new C(0);
shared c1 = new shared C(1);
immutable c2 = new immutable C(2);
You only need one of the constructors depending on if you want a
__gshared, shared or immutable variable.
PS: I take the opportnity to ask if I can count on the compiler to
intern literal strings (which my code may use in several places,
including loops), esp. "", or should I declare and use (for instance):
static immutable s0 = "" ;
String literals are stored in the executable. Each unique string literal
is only stored once.
--
/Jacob Carlborg
Re: local class instance (at module-level)
On 14/03/2019 12:16, H. S. Teoh via Digitalmars-d-learn wrote:
On Thu, Mar 14, 2019 at 12:05:22PM +0100, spir via Digitalmars-d-learn wrote:
I desperately try to declare/define/initialise a simple class instance
at module-level. This is a special (conceptually static and immutable)
instance used as a "marker", that just should exist and be accessible
by methods of this class and/or other classes defined in the same
module. (Thus I don't care if TLS.) I use it as a remplacement for
null, to avoid semantic confusion and unhelpful segfaults in case of
bug.
Does this work?
class C { ... }
immutable C c0;
static this() {
c0 = new C(...);
}
T
Oh yes, that was it ! Thank you very much.
diniz
Re: local class instance (at module-level)
On Thursday, 14 March 2019 at 11:05:22 UTC, spir wrote:
I desperately try to declare/define/initialise a simple class
instance at module-level. This is a special (conceptually
static and immutable) instance used as a "marker", that just
should exist and be accessible by methods of this class and/or
other classes defined in the same module. (Thus I don't care if
TLS.) I use it as a remplacement for null, to avoid semantic
confusion and unhelpful segfaults in case of bug.
I have tried a number of options and never manage to do it,
including:
* [C/auto/static immutable c0] = new C(0) ;
* C c0 ; c0.i = 0 ;
* defining a static this()
* more...
The most confusing error is:
Error: variable `_base.c0` is a thread-local class and cannot
have a static initializer. Use `static this()` to initialize
instead.
I also could not find any information --for a while,
repeatedly, since I can go on developing in the meantime, using
null instead. I'm bluffed and confused, since there is nothing
weird in that, is there? (the compiler can just allocate it in
static mem and take the address)
Reduced test case:
===
class C {
uint i ;
this (uint i) {
this.i = i ;
}
}
// error
auto c0 = new C(0) ;
void main () {
// ok
auto c0 = new C(0) ;
}
===
I would enjoy an explanation (or a pointer to) in addition to a
solution.
Thank you,
diniz
PS: I take the opportnity to ask if I can count on the compiler
to intern literal strings (which my code may use in several
places, including loops), esp. "", or should I declare and use
(for instance):
static immutable s0 = "" ;
Basically, this works for me:
´´´
class C {
uint i ;
this (uint i) {
this.i = i ;
}
}
C c0;
static this()
{
c0 = new C(0);
}
void main () {
assert(!(c0 is null));
}
´´´
Re: local class instance (at module-level)
On Thursday, 14 March 2019 at 11:05:22 UTC, spir wrote:
The most confusing error is:
Error: variable `_base.c0` is a thread-local class and cannot
have a static initializer. Use `static this()` to initialize
instead.
Error is reffering to:
https://dlang.org/spec/module.html#staticorder
You can do this:
C c0;
static this()
{
c0 = new C();
}
Andrea
Re: local class instance (at module-level)
On Thu, Mar 14, 2019 at 12:05:22PM +0100, spir via Digitalmars-d-learn wrote:
> I desperately try to declare/define/initialise a simple class instance
> at module-level. This is a special (conceptually static and immutable)
> instance used as a "marker", that just should exist and be accessible
> by methods of this class and/or other classes defined in the same
> module. (Thus I don't care if TLS.) I use it as a remplacement for
> null, to avoid semantic confusion and unhelpful segfaults in case of
> bug.
Does this work?
class C { ... }
immutable C c0;
static this() {
c0 = new C(...);
}
T
--
To err is human; to forgive is not our policy. -- Samuel Adler
local class instance (at module-level)
I desperately try to declare/define/initialise a simple class instance at
module-level. This is a special (conceptually static and immutable) instance
used as a "marker", that just should exist and be accessible by methods of this
class and/or other classes defined in the same module. (Thus I don't care if
TLS.) I use it as a remplacement for null, to avoid semantic confusion and
unhelpful segfaults in case of bug.
I have tried a number of options and never manage to do it, including:
* [C/auto/static immutable c0] = new C(0) ;
* C c0 ; c0.i = 0 ;
* defining a static this()
* more...
The most confusing error is:
Error: variable `_base.c0` is a thread-local class and cannot have a static
initializer. Use `static this()` to initialize instead.
I also could not find any information --for a while, repeatedly, since I can go
on developing in the meantime, using null instead. I'm bluffed and confused,
since there is nothing weird in that, is there? (the compiler can just allocate
it in static mem and take the address)
Reduced test case:
===
class C {
uint i ;
this (uint i) {
this.i = i ;
}
}
// error
auto c0 = new C(0) ;
void main () {
// ok
auto c0 = new C(0) ;
}
===
I would enjoy an explanation (or a pointer to) in addition to a solution.
Thank you,
diniz
PS: I take the opportnity to ask if I can count on the compiler to intern
literal strings (which my code may use in several places, including loops), esp.
"", or should I declare and use (for instance):
static immutable s0 = "" ;
