Re: Capturing caller's file/line number in variadic template functions
On Friday, 16 March 2012 at 18:21:54 UTC, H. S. Teoh wrote:
void checkConsistency(T...)(T args, string file=__FILE__,
size_t line=__LINE__) { ... }
but this causes compile errors because when C==string, then the
call is
ambiguous.
Does it make sense to consider to add a new type to hold the file
name and line? So the types clash can be avoided:
class file_line
{
this(string f=__FILE__, size_t ln=__LINE__)
{
file = f;
line = ln;
}
string file;
size_t line;
};
void checkConsistency(T...)
(T args, file_line pos = new file_line) {...}
checkConsistency!(A,B,C)(a,b,c);
Seems to work, but requires an explicit checkConsistency call - I
didn't manage to make it implicit.
Re: Capturing caller's file/line number in variadic template functions
On Fri, 16 Mar 2012 14:41:40 -0400, H. S. Teoh wrote: On Fri, Mar 16, 2012 at 02:30:25PM -0400, Steven Schveighoffer wrote: [...] I know this is already answered, but do you get a stack trace? Shouldn't the second stack frame point to the offending line? [...] I didn't compile with debugging turned on, so it only showed a hex address. Using compile-time args for __FILE__ and __LINE__ lets me see the offending line even when debug is off. (And actually, the offending line is several frames down; the top few frames look like unittest scaffolding the compiler inserted for catching assert errors and handling unittest-specific stuff. Kinda painful to figure out where the problem is if a straight error message will tell you immediately. :-)) Right, but I dislike this sort of boilerplaty stuff, especially for unit tests. It should be avoidable... -Steve
Re: Capturing caller's file/line number in variadic template functions
16.03.2012 20:35, H. S. Teoh пишет:
[...]
Actually, I found the solution: the compiler understands __FILE__ and
__LINE__ in compile-time arguments too, so this works: void
checkConsistency(string file=__FILE__, size_t line=__LINE__, T...)(T
args) { ... } It's a bit painful with the assert statement, because it
doesn't let you control the file/line number of the AssertError, but
this can be worked around by using std.string.format:
assert(isConsistent(a), "inconsistency found in
%s(%d)".format(file,line)); The AssertError will still point to
checkConsistency, but the error message will tell you where the caller
is. T
Yes, but the code is duplicated per every instance of template, and
template is instantiated whenever it's CT-parameters change. This isn't
much of a problem with functions that are meant to run at compile-time
only (except that static locals will not work properly), but for
run-time functions that may be undesired.
Re: Capturing caller's file/line number in variadic template functions
On Fri, Mar 16, 2012 at 02:30:25PM -0400, Steven Schveighoffer wrote: [...] > I know this is already answered, but do you get a stack trace? > Shouldn't the second stack frame point to the offending line? [...] I didn't compile with debugging turned on, so it only showed a hex address. Using compile-time args for __FILE__ and __LINE__ lets me see the offending line even when debug is off. (And actually, the offending line is several frames down; the top few frames look like unittest scaffolding the compiler inserted for catching assert errors and handling unittest-specific stuff. Kinda painful to figure out where the problem is if a straight error message will tell you immediately. :-)) T -- Indifference will certainly be the downfall of mankind, but who cares? -- Miquel van Smoorenburg
Re: Capturing caller's file/line number in variadic template functions
On Friday, 16 March 2012 at 18:31:58 UTC, Kevin Cox wrote: But then you have to write it each time. Nah, it just works, at least for the implicit calls: checkConsistency(1, "2", 3); // calls checkConsistenct!(__FILE__, __LINE__, int, string, int)(1, "2", 3);
Re: Capturing caller's file/line number in variadic template functions
On Fri, Mar 16, 2012 at 02:31:47PM -0400, Kevin Cox wrote:
> On Mar 16, 2012 2:29 PM, "Adam D. Ruppe" wrote:
> >
> > Put the string file = blaha in the template argument list,
> > before the variadic.
> >
> > voic checkConsistency(string file = __FILE__, int line = __LINE__,
> T...)(T t) {
> >
> >
> But then you have to write it each time.
No you don't. The compiler automatically infers the compile-time
arguments for you. This works:
int a;
char b;
float c;
checkConsistency(a,b,c);
// Gets translated to:
checkConsistency!(__FILE__, __LINE__, int, char, float)(a,b,c);
exactly as I wanted.
T
--
People say I'm arrogant, but they're just ignorant fools.
Re: Capturing caller's file/line number in variadic template functions
On Fri, 16 Mar 2012 14:23:37 -0400, H. S. Teoh
wrote:
I'm writing some unittests with very repetitive tests for a myriad of
different types, so I wrote a helper function:
version(unittest) {
void checkConsistency(T...)(T args) {
foreach (a; args) {
assert(isConsistent(a));
}
}
}
unittest {
A a;
B b;
C c;
checkConsistency(a,b,c);
}
However, when a consistency check fails, the assert error points to
checkConsistency instead of the unittest, so it's a pain trying to
figure out exactly which test case failed.
I know this is already answered, but do you get a stack trace? Shouldn't
the second stack frame point to the offending line?
-Steve
Re: Capturing caller's file/line number in variadic template functions
On Fri, Mar 16, 2012 at 08:26:30PM +0200, Mantis wrote:
> 16.03.2012 20:23, H. S. Teoh пишет:
> >I'm writing some unittests with very repetitive tests for a myriad of
> >different types, so I wrote a helper function:
> >
> > version(unittest) {
> > void checkConsistency(T...)(T args) {
> > foreach (a; args) {
> > assert(isConsistent(a));
> > }
> > }
> > }
> > unittest {
> > A a;
> > B b;
> > C c;
> > checkConsistency(a,b,c);
> > }
> >
> >However, when a consistency check fails, the assert error points to
> >checkConsistency instead of the unittest, so it's a pain trying to
> >figure out exactly which test case failed. I tried adding default
> >arguments to checkConsistency:
> >
> > void checkConsistency(T...)(T args, string file=__FILE__,
> > size_t line=__LINE__) { ... }
> >
> >but this causes compile errors because when C==string, then the call is
> >ambiguous.
[...]
> What happens if you insert some dummy type ?:
>
> void checkConsistency(T...)(T args, Delimiter dm = Delimiter.init,
> string file=__FILE__, size_t line=__LINE__) { ... }
Actually, I found the solution: the compiler understands __FILE__ and
__LINE__ in compile-time arguments too, so this works:
void checkConsistency(string file=__FILE__, size_t
line=__LINE__, T...)(T args)
{
...
}
It's a bit painful with the assert statement, because it doesn't let you
control the file/line number of the AssertError, but this can be worked
around by using std.string.format:
assert(isConsistent(a),
"inconsistency found in %s(%d)".format(file,line));
The AssertError will still point to checkConsistency, but the error
message will tell you where the caller is.
T
--
The early bird gets the worm. Moral: ewww...
Re: Capturing caller's file/line number in variadic template functions
On Mar 16, 2012 2:29 PM, "Adam D. Ruppe" wrote:
>
> Put the string file = blaha in the template argument list,
> before the variadic.
>
> voic checkConsistency(string file = __FILE__, int line = __LINE__,
T...)(T t) {
>
>
But then you have to write it each time.
Re: Capturing caller's file/line number in variadic template functions
On Friday, 16 March 2012 at 18:21:54 UTC, H. S. Teoh wrote:
void checkConsistency(T...)(T args, string file=__FILE__,
size_t line=__LINE__) { ... }
but this causes compile errors because when C==string, then the
call is
ambiguous.
Is there an easy of working around this?
Put the string file = blaha in the template argument list,
before the variadic.
voic checkConsistency(string file = __FILE__, int line =
__LINE__, T...)(T t) {
Re: Capturing caller's file/line number in variadic template functions
16.03.2012 20:23, H. S. Teoh пишет:
I'm writing some unittests with very repetitive tests for a myriad of
different types, so I wrote a helper function:
version(unittest) {
void checkConsistency(T...)(T args) {
foreach (a; args) {
assert(isConsistent(a));
}
}
}
unittest {
A a;
B b;
C c;
checkConsistency(a,b,c);
}
However, when a consistency check fails, the assert error points to
checkConsistency instead of the unittest, so it's a pain trying to
figure out exactly which test case failed. I tried adding default
arguments to checkConsistency:
void checkConsistency(T...)(T args, string file=__FILE__,
size_t line=__LINE__) { ... }
but this causes compile errors because when C==string, then the call is
ambiguous.
Is there an easy of working around this?
T
What happens if you insert some dummy type ?:
void checkConsistency(T...)(T args, Delimiter dm = Delimiter.init,
string file=__FILE__, size_t line=__LINE__) { ... }
Capturing caller's file/line number in variadic template functions
I'm writing some unittests with very repetitive tests for a myriad of
different types, so I wrote a helper function:
version(unittest) {
void checkConsistency(T...)(T args) {
foreach (a; args) {
assert(isConsistent(a));
}
}
}
unittest {
A a;
B b;
C c;
checkConsistency(a,b,c);
}
However, when a consistency check fails, the assert error points to
checkConsistency instead of the unittest, so it's a pain trying to
figure out exactly which test case failed. I tried adding default
arguments to checkConsistency:
void checkConsistency(T...)(T args, string file=__FILE__,
size_t line=__LINE__) { ... }
but this causes compile errors because when C==string, then the call is
ambiguous.
Is there an easy of working around this?
T
--
To err is human; to forgive is not our policy. -- Samuel Adler
