Re: variable _param_0 cannot be read at compile time
On Thursday, 9 August 2018 at 13:42:03 UTC, Kagamin wrote:
struct M {
int i;
S*[100] s;
}
struct S {
M* mp;
bool x;
}
S* add(A...)() {
alias m = A[0];
__gshared s = S(,A[1..$]);
m.s[m.i++] =
return
}
void main(){
__gshared M m = M(0);
__gshared S s = S(, false);
m.s[m.i++] =
auto p = add!(m, true);
}
this is what I want! thanks.
Re: How do you put log calls in constructors when they may be created in a static context?
On Thursday, 9 August 2018 at 20:02:41 UTC, Jonathan M Davis
wrote:
On Thursday, August 9, 2018 7:15:58 AM MDT aliak via
Digitalmars-d-learn wrote:
[...]
It's failing, because you got the condition backwards. __ctfe
is true during CTFE and false during runtime. Your code has
if(__ctfe)
writeln("log it");
which means that it will attempt to run writeln at compile
time, whereas if you used
if(!__ctfe)
writeln("log it");
it would skip it at compile time. The problem isn't that
writeln is being compiled in. The problem is that it's being
encountered when CTFE is running the code. So, a static if is
unnecessary. You just need to get the condition right.
- Jonathan M Davis
Haha doh! Backwards it was. Thanks!
vibe.d: Finding out if currently in webinterface request
I already posted this in the vibe.d forums (https://forum.rejectedsoftware.com/groups/rejectedsoftware.vibed/thread/58891/), but it seems, there is not a lot of activity over there, so I am cross posting this here: Is there a way to find out, if we are currently in a webinterface request? My usecase is the following: I want to implement a logger, which in addition to the actual log message also logs information about the request which is currently being handled (if any). For this I would like to call request(), which gives me the current HTTPServerRequest. However, this results in an AssertError, whenever logging appears outside of a webinterface request (so basically immediately after starting the application, because vibe.d logs some things automatically). So I would need to check, if we are currently processing a webinterface request. Another usecase which would be interesting to me and which has the exact same problem is the following: Suppose in my received request, there is an HTTP header X-Correlation-Id: . Now whenever during processing of this request I start an HTTP request to some other service (e.g. via requestHTTP()), I also want to include this header in the new request I send. Of course, you could implement this by always passing the header manually, but I'd prefer to implement this using a generalized wrapper around requestHTTP(). But then in this wrapper, I would also need to call request(), which makes it impossible to call it from outside of webinterface request (e.g. it could be triggered by a timer, or something like this). But it would be nice, to be able to just use a single function for all my requests (to keep things uniform).
Re: How do you put log calls in constructors when they may be created in a static context?
On Thursday, August 9, 2018 7:15:58 AM MDT aliak via Digitalmars-d-learn
wrote:
> On Thursday, 9 August 2018 at 12:01:42 UTC, Jonathan M Davis
>
> wrote:
> > On Thursday, August 9, 2018 2:37:49 AM MDT aliak via
> >
> > Digitalmars-d-learn wrote:
> >> On Wednesday, 8 August 2018 at 23:47:22 UTC, Jonathan M Davis
> >>
> >> wrote:
> >> > On Wednesday, August 8, 2018 3:54:34 PM MDT aliak via
> >> >
> >> > Digitalmars-d-learn wrote:
> >> >> I'm trying to debug stuff, so I want to add verbose logging
> >> >>
> >> >> struct S(T) {
> >> >>
> >> >>this() {
> >> >>
> >> >> writeln("created S(T) with properties and ID");
> >> >>
> >> >>}
> >> >>
> >> >> }
> >> >>
> >> >> static a = S!int(); // bah
> >> >>
> >> >> I guess users can call this code from any context, but when
> >> >> i'd also like to see the log output for debugging purposes.
> >> >> Is there a way around this?
> >> >>
> >> >> Can I maybe only do a writeln in a non compile-time context?
> >> >
> >> > if(__ctfe)
> >> > {
> >> >
> >> > // code here will execute if this is encountered during
> >> >
> >> > CTFE
> >> >
> >> > }
> >> > else
> >> > {
> >> >
> >> > // code here will execute if this is encountered outside
> >> >
> >> > of
> >> >
> >> > CTFE
> >> > }
> >> >
> >> > - Jonathan M Davis
> >>
> >> That won't work because __ctfe is not readable at compile
> >> time. And I don't want that writeln there when there's compile
> >> time evaluation because errors.
> >
> > Huh? __ctfe's entire purpose is so that you can differentiate
> > between code that's run at compile-time and code that's run at
> > runtime. If a piece of code is executed at compile-time, __ctfe
> > is true, whereas if it's executed at runtime, __ctfe is false.
> > So, if you have
> >
> > this(T i)
> > {
> >
> > if(!__ctfe)
> >
> > writeln("log it");
> >
> > }
> >
> > then the code will print "log it" if the object is constructed
> > at runtime, whereas it won't print anything if it's run at
> > compile time, and there won't be any errors for trying to call
> > writeln at compile time, because it will have been skipped.
> >
> > - Jonathan M Davis
>
> Maybe I'm just explaining what I'm trying to do wrong, but that
> code doesn't compile when "this" is called in a valid compile
> time evaluation context, you'll get errors:
> https://run.dlang.io/is/KiJrR1
>
> That link contains the gist of what I want to do. If you could
> static if (__ctfe) ... then that'd work but I don't know if
> there's something like that. Alternatively, if I can get a non
> compile time evaluated static then that also will do the trick.
It's failing, because you got the condition backwards. __ctfe is true during
CTFE and false during runtime. Your code has
if(__ctfe)
writeln("log it");
which means that it will attempt to run writeln at compile time, whereas if
you used
if(!__ctfe)
writeln("log it");
it would skip it at compile time. The problem isn't that writeln is being
compiled in. The problem is that it's being encountered when CTFE is running
the code. So, a static if is unnecessary. You just need to get the condition
right.
- Jonathan M Davis
Re: variable _param_0 cannot be read at compile time
struct M {
int i;
S*[100] s;
}
struct S {
M* mp;
bool x;
}
S* add(A...)() {
alias m = A[0];
__gshared s = S(,A[1..$]);
m.s[m.i++] =
return
}
void main(){
__gshared M m = M(0);
__gshared S s = S(, false);
m.s[m.i++] =
auto p = add!(m, true);
}
Re: How do you put log calls in constructors when they may be created in a static context?
On Thursday, 9 August 2018 at 12:01:42 UTC, Jonathan M Davis
wrote:
On Thursday, August 9, 2018 2:37:49 AM MDT aliak via
Digitalmars-d-learn wrote:
On Wednesday, 8 August 2018 at 23:47:22 UTC, Jonathan M Davis
wrote:
> On Wednesday, August 8, 2018 3:54:34 PM MDT aliak via
>
> Digitalmars-d-learn wrote:
>> I'm trying to debug stuff, so I want to add verbose logging
>>
>> struct S(T) {
>>
>>this() {
>>
>> writeln("created S(T) with properties and ID");
>>
>>}
>>
>> }
>>
>> static a = S!int(); // bah
>>
>> I guess users can call this code from any context, but when
>> i'd also like to see the log output for debugging purposes.
>> Is there a way around this?
>>
>> Can I maybe only do a writeln in a non compile-time context?
>
> if(__ctfe)
> {
>
> // code here will execute if this is encountered during
> CTFE
>
> }
> else
> {
>
> // code here will execute if this is encountered outside
> of
>
> CTFE
> }
>
> - Jonathan M Davis
That won't work because __ctfe is not readable at compile
time. And I don't want that writeln there when there's compile
time evaluation because errors.
Huh? __ctfe's entire purpose is so that you can differentiate
between code that's run at compile-time and code that's run at
runtime. If a piece of code is executed at compile-time, __ctfe
is true, whereas if it's executed at runtime, __ctfe is false.
So, if you have
this(T i)
{
if(!__ctfe)
writeln("log it");
}
then the code will print "log it" if the object is constructed
at runtime, whereas it won't print anything if it's run at
compile time, and there won't be any errors for trying to call
writeln at compile time, because it will have been skipped.
- Jonathan M Davis
Maybe I'm just explaining what I'm trying to do wrong, but that
code doesn't compile when "this" is called in a valid compile
time evaluation context, you'll get errors:
https://run.dlang.io/is/KiJrR1
That link contains the gist of what I want to do. If you could
static if (__ctfe) ... then that'd work but I don't know if
there's something like that. Alternatively, if I can get a non
compile time evaluated static then that also will do the trick.
Re: How do you put log calls in constructors when they may be created in a static context?
On Thursday, August 9, 2018 2:37:49 AM MDT aliak via Digitalmars-d-learn
wrote:
> On Wednesday, 8 August 2018 at 23:47:22 UTC, Jonathan M Davis
>
> wrote:
> > On Wednesday, August 8, 2018 3:54:34 PM MDT aliak via
> >
> > Digitalmars-d-learn wrote:
> >> I'm trying to debug stuff, so I want to add verbose logging
> >>
> >> struct S(T) {
> >>
> >>this() {
> >>
> >> writeln("created S(T) with properties and ID");
> >>
> >>}
> >>
> >> }
> >>
> >> static a = S!int(); // bah
> >>
> >> I guess users can call this code from any context, but when
> >> i'd also like to see the log output for debugging purposes. Is
> >> there a way around this?
> >>
> >> Can I maybe only do a writeln in a non compile-time context?
> >
> > if(__ctfe)
> > {
> >
> > // code here will execute if this is encountered during CTFE
> >
> > }
> > else
> > {
> >
> > // code here will execute if this is encountered outside of
> >
> > CTFE
> > }
> >
> > - Jonathan M Davis
>
> That won't work because __ctfe is not readable at compile time.
> And I don't want that writeln there when there's compile time
> evaluation because errors.
Huh? __ctfe's entire purpose is so that you can differentiate between code
that's run at compile-time and code that's run at runtime. If a piece of
code is executed at compile-time, __ctfe is true, whereas if it's executed
at runtime, __ctfe is false. So, if you have
this(T i)
{
if(!__ctfe)
writeln("log it");
}
then the code will print "log it" if the object is constructed at runtime,
whereas it won't print anything if it's run at compile time, and there won't
be any errors for trying to call writeln at compile time, because it will
have been skipped.
- Jonathan M Davis
Re: How do you put log calls in constructors when they may be created in a static context?
On Wednesday, 8 August 2018 at 23:47:22 UTC, Jonathan M Davis
wrote:
On Wednesday, August 8, 2018 3:54:34 PM MDT aliak via
Digitalmars-d-learn wrote:
I'm trying to debug stuff, so I want to add verbose logging
struct S(T) {
this() {
writeln("created S(T) with properties and ID");
}
}
static a = S!int(); // bah
I guess users can call this code from any context, but when
i'd also like to see the log output for debugging purposes. Is
there a way around this?
Can I maybe only do a writeln in a non compile-time context?
if(__ctfe)
{
// code here will execute if this is encountered during CTFE
}
else
{
// code here will execute if this is encountered outside of
CTFE
}
- Jonathan M Davis
That won't work because __ctfe is not readable at compile time.
And I don't want that writeln there when there's compile time
evaluation because errors.
1) I want to be able to log when a type is created
2) I want to declare a locally static runtime type
Ie:
import std.stdio;
struct S(T) {
T i;
this(T i) {
this.i = i;
writeln("log it");
}
}
int f() {
static x = S!int(3);
return x.i++;
}
void main() {
writeln(f); // print 3
writeln(f); // print 4
}
