Re: Creating a new type, to get strong-ish type checking and restrict usage to certain operations, using struct perhaps
On Friday, 21 July 2017 at 18:49:21 UTC, Cecil Ward wrote: I was think about how to create a new type that holds packed bcd values, of a choice of widths, that must fit into a uint32_t or a uint64_t (not really long multi-byte objects). I am not at all sure how to do it. I thought about using a templated struct to simply wrap a uint of a chosen width, and perhaps use alias this to make things nicer. I guess part of my question, which I didn't really highlight well enough, is the issue of strong typing. Example: physical units types, such as amps and volts, implemented as say a double or float or real (want to template that) but disallow evil assignments, comparisons, addition etc of mixed types. Another one would be the prevention of mixing pounds and pence by straight addition, or straight comparisons and blocking straight assignment. I'm assuming in the latter case you might use a machine-architecture native integral type of whatever width, again templating wanted. These are all really old requests, I'm sure, but I would appreciate a start as to how to implement the strong type checking in D without too much pain. Going back to the original example of packed bcd stored in a uint64_t say, first thing is that I want to ban illegal mixing of arbitrary binary values in ordinary uint64_tmtypes with decimal types, again no assignment, addition, comoarisons etc across types at all allowed. And no friendly automagically conversions from packed bcd to binary on the fly either - I want to treat that kind of usage as a straight bug by the user, for the moment at least, anyway, as I don't want to encourage silent horrible inefficiency creeping in.
Re: find difference between two struct instances.
On Saturday, 22 July 2017 at 01:04:48 UTC, Nicholas Wilson wrote:
On Friday, 21 July 2017 at 23:38:51 UTC, FoxyBrown wrote:
[...]
use opCmp in conjunction with __traits(allMembers,T)
struct Example
{
int a,b,c;
string d,e,f;
}
void difference(alias func, T)(T t1, T t2)
if(__traits(compiles, func(t1,t2)))
{
foreach(U; __traits(allMembers,T)
{
if (mixin("t1." ~ U.stringof~ ".opCmp(t2." ~ U.stringof
~")")
func(t1,t2);
}
}
auto a = Example(1,2,3,"foo","bar",baz");
auto a = Example(1,2,42,"foo","bar",quux");
difference!(writeln)(a,b); // hopefully prints 343\nbazquux
Not tested but should give you an idea to adapt as needed.
thanks, I'll try it out.
Re: executeShell not working
On Saturday, 22 July 2017 at 02:31:45 UTC, FoxyBrown wrote:
auto sss = "sc config \""~szSvcName~"\" start= disabled";
executeShell("sc config \""~szSvcName~"\" start= disabled");
but if I copy and paste the string in to an admin console, it
works fine:
sc config "W32Time" start= disabled
[SC] ChangeServiceConfig SUCCESS
szSvcName is W32Time.
It's not an admin issue.
I *can't* set it to other states either. Does executeShell not
run it's process with the same rights as the app?
even spawnProcess isn't doing it
spawnProcess(["C:\\Windows\\System32\\sc.exe","config",
szSvcName, "start=","disabled"]);
or
spawnProcess(["C:\\Windows\\System32\\sc.exe","config
"~szSvcName~" start= disabled"]);
executeShell not working
auto sss = "sc config \""~szSvcName~"\" start= disabled";
executeShell("sc config \""~szSvcName~"\" start= disabled");
but if I copy and paste the string in to an admin console, it
works fine:
sc config "W32Time" start= disabled
[SC] ChangeServiceConfig SUCCESS
szSvcName is W32Time.
It's not an admin issue.
I *can't* set it to other states either. Does executeShell not
run it's process with the same rights as the app?
Re: How can I serialize a struct into a file in the style of C?
On Saturday, 22 July 2017 at 02:11:27 UTC, Mike Parker wrote:
On Saturday, 22 July 2017 at 01:45:29 UTC, solidstate1991 wrote:
Due to it's convenience, I was thinking on reading and writing
file headers by creating structs mirroring the layouts of
actual headers I would need. I've seen many examples of this
in C, however I' struggling using the same methods through the
use of code.stdc.stdio, especially as I can't really trace
bugs from fread.
struct Data {
int x;
float y;
ubyte z;
}
void main() {
import core.stdc.stdio;
Data od = Data(10, 3.0f, 5);
FILE* fp = fopen("data.dat", "wb");
size_t ret = fwrite(, od.sizeof, 1, fp);
fclose(fp);
assert(ret == 1);
Data id;
fp = fopen("data.dat", "rb");
ret = fread(, id.sizeof, 1, fp);
fclose(fp);
assert(ret == 1);
assert(id.x == 10);
assert(id.y == 3.0f);
assert(id.z == 5);
}
I should add, though, that you're better off using either
std.stdio.File or std.file. Use the former if you need to make
multiple reads/writes to a file, the latter if you can pull it in
or push it out all in one go. They take arrays as arguments, so
if you have something like Data[], you can pass it directly to
the appropriate functions. To write a single instance, you'll
have to take the pointer and slice it. Either way, it's less
code, less error prone, and more idiomatic than using the C API.
Re: How can I serialize a struct into a file in the style of C?
On Saturday, 22 July 2017 at 01:45:29 UTC, solidstate1991 wrote:
Due to it's convenience, I was thinking on reading and writing
file headers by creating structs mirroring the layouts of
actual headers I would need. I've seen many examples of this in
C, however I' struggling using the same methods through the use
of code.stdc.stdio, especially as I can't really trace bugs
from fread.
struct Data {
int x;
float y;
ubyte z;
}
void main() {
import core.stdc.stdio;
Data od = Data(10, 3.0f, 5);
FILE* fp = fopen("data.dat", "wb");
size_t ret = fwrite(, od.sizeof, 1, fp);
fclose(fp);
assert(ret == 1);
Data id;
fp = fopen("data.dat", "rb");
ret = fread(, id.sizeof, 1, fp);
fclose(fp);
assert(ret == 1);
assert(id.x == 10);
assert(id.y == 3.0f);
assert(id.z == 5);
}
How can I serialize a struct into a file in the style of C?
Due to it's convenience, I was thinking on reading and writing file headers by creating structs mirroring the layouts of actual headers I would need. I've seen many examples of this in C, however I' struggling using the same methods through the use of code.stdc.stdio, especially as I can't really trace bugs from fread.
Re: Cannot find std.datetime when linking after upgrade to 2.075.0
On Friday, 21 July 2017 at 19:05:00 UTC, Jonathan M Davis wrote: On Friday, July 21, 2017 15:33:45 Domain via Digitalmars-d-learn wrote: After upgrade dmd to latest 2.075.0, my project no longer build: zero.lib(core_cde_4a4f.obj) : error LNK2001: unresolved external symbol _D3std8d atetime9LocalTime6opCallFNaNbNeZyC3std8datetime9LocalTime and many more. All about std.datetime. Then it sounds like you need to make sure that you rebuild your project and all of its dependencies (which you should be doing with any compiler upgrade anyway, since they're not ABI compatible). Your code should work just fine with std.datetime and 2.075.0 without any changes, but it will need to be recompiled. https://dlang.org/changelog/2.075.0.html#split-std-datetime - Jonathan M Davis I have tried dub build --force and rebuild solution in VisualD, but nothing changed. Maybe I have to remove the lib manually.
Re: find difference between two struct instances.
On Friday, 21 July 2017 at 23:38:51 UTC, FoxyBrown wrote:
On Friday, 21 July 2017 at 22:35:20 UTC, Era Scarecrow wrote:
On Friday, 21 July 2017 at 21:03:22 UTC, FoxyBrown wrote:
Is there a way to easily find the differences between to
struct instances? I would like to report only the differences
e.g.,
writeln(s1 - s2);
prints only what is different between s1 and s2.
No, it isn't. It is a concept, wasn't mean to be taken as
literal D code.
This is entirely dependent on the structs in question, you
can't just subtract any struct from another struct unless it
knows how to do it.
Depends on what the structures hold. You'll probably have to
either make an opSub, a function to call opBinary!"-", or do
opCmp which returns which is higher/lower (and may be as
simple as subtraction).
Why do I want to go through all that trouble? A simple binary
compare should suffice.
use opCmp in conjunction with __traits(allMembers,T)
struct Example
{
int a,b,c;
string d,e,f;
}
void difference(alias func, T)(T t1, T t2) if(__traits(compiles,
func(t1,t2)))
{
foreach(U; __traits(allMembers,T)
{
if (mixin("t1." ~ U.stringof~ ".opCmp(t2." ~ U.stringof
~")")
func(t1,t2);
}
}
auto a = Example(1,2,3,"foo","bar",baz");
auto a = Example(1,2,42,"foo","bar",quux");
difference!(writeln)(a,b); // hopefully prints 343\nbazquux
Not tested but should give you an idea to adapt as needed.
Re: find difference between two struct instances.
On Friday, 21 July 2017 at 22:35:20 UTC, Era Scarecrow wrote: On Friday, 21 July 2017 at 21:03:22 UTC, FoxyBrown wrote: Is there a way to easily find the differences between to struct instances? I would like to report only the differences e.g., writeln(s1 - s2); prints only what is different between s1 and s2. No, it isn't. It is a concept, wasn't mean to be taken as literal D code. This is entirely dependent on the structs in question, you can't just subtract any struct from another struct unless it knows how to do it. Depends on what the structures hold. You'll probably have to either make an opSub, a function to call opBinary!"-", or do opCmp which returns which is higher/lower (and may be as simple as subtraction). Why do I want to go through all that trouble? A simple binary compare should suffice.
Re: find difference between two struct instances.
On Friday, 21 July 2017 at 21:03:22 UTC, FoxyBrown wrote: Is there a way to easily find the differences between to struct instances? I would like to report only the differences e.g., writeln(s1 - s2); prints only what is different between s1 and s2. This is entirely dependent on the structs in question, you can't just subtract any struct from another struct unless it knows how to do it. Depends on what the structures hold. You'll probably have to either make an opSub, a function to call opBinary!"-", or do opCmp which returns which is higher/lower (and may be as simple as subtraction).
find difference between two struct instances.
Is there a way to easily find the differences between to struct instances? I would like to report only the differences e.g., writeln(s1 - s2); prints only what is different between s1 and s2.
Re: Creating a new type, to get strong-ish type checking and restrict usage to certain operations, using struct perhaps
On 07/21/2017 11:49 AM, Cecil Ward wrote: I was think about how to create a new type that holds packed bcd values, of a choice of widths, that must fit into a uint32_t or a uint64_t (not really long multi-byte objects). I am not at all sure how to do it. I thought about using a templated struct to simply wrap a uint of a chosen width, and perhaps use alias this to make things nicer. Andrei's checkedint may give ideas: https://dlang.org/phobos/std_experimental_checkedint.html He presented it in this talk: http://dconf.org/2017/talks/alexandrescu.html ... which is missing the following video link: https://www.youtube.com/watch?v=29h6jGtZD-U ... which has a longer version: https://www.youtube.com/watch?v=es6U7WAlKpQ Ali
Re: Creating a new type, to get strong-ish type checking and restrict usage to certain operations, using struct perhaps
On Friday, 21 July 2017 at 18:49:21 UTC, Cecil Ward wrote:
I was think about how to create a new type that holds packed
bcd values, of a choice of widths, that must fit into a
uint32_t or a uint64_t (not really long multi-byte objects). I
am not at all sure how to do it. I thought about using a
templated struct to simply wrap a uint of a chosen width, and
perhaps use alias this to make things nicer.
That's usually how this is done. Take a look at the new
std.experimental.checkedint for inspiration [1].
Here's a shell to start with (fill in:
---
struct BCDInteger(ubyte bitWidth) if (bitWidth <= 128)
{
private:
enum byteWidth = // Add bit to byte width conversion (or just
take byte width as template parameter)
ubyte[byteWidth] store;
public:
// Add constructor(s)/static factory functions
// Overload operators,
// Add conversions to other integer formats
// Add alias this for conversion to two complements format
}
---
[1]
https://github.com/dlang/phobos/blob/v2.075.0/std/experimental/checkedint.d#L213
Re: Cannot find std.datetime when linking after upgrade to 2.075.0
On Friday, July 21, 2017 15:33:45 Domain via Digitalmars-d-learn wrote: > After upgrade dmd to latest 2.075.0, my project no longer build: > > zero.lib(core_cde_4a4f.obj) : error LNK2001: unresolved external > symbol _D3std8d > atetime9LocalTime6opCallFNaNbNeZyC3std8datetime9LocalTime > > and many more. All about std.datetime. Then it sounds like you need to make sure that you rebuild your project and all of its dependencies (which you should be doing with any compiler upgrade anyway, since they're not ABI compatible). Your code should work just fine with std.datetime and 2.075.0 without any changes, but it will need to be recompiled. https://dlang.org/changelog/2.075.0.html#split-std-datetime - Jonathan M Davis
Creating a new type, to get strong-ish type checking and restrict usage to certain operations, using struct perhaps
I was think about how to create a new type that holds packed bcd values, of a choice of widths, that must fit into a uint32_t or a uint64_t (not really long multi-byte objects). I am not at all sure how to do it. I thought about using a templated struct to simply wrap a uint of a chosen width, and perhaps use alias this to make things nicer.
Re: Cannot find std.datetime when linking after upgrade to 2.075.0
https://dlang.org/changelog/2.075.0.html#split-std-datetime
Cannot find std.datetime when linking after upgrade to 2.075.0
After upgrade dmd to latest 2.075.0, my project no longer build: zero.lib(core_cde_4a4f.obj) : error LNK2001: unresolved external symbol _D3std8d atetime9LocalTime6opCallFNaNbNeZyC3std8datetime9LocalTime and many more. All about std.datetime.
Re: Check whether string value represents a type
On 7/21/17 10:21 AM, Timoses wrote:
I'd love to check whether a string value is the name of a type at run-time.
E.g.:
string a = "int";
string b = "im no type";
assert( isStringType(a) );
assert( !isStringType(b) );
or
struct TestStruct
{
int test;
}
string t = "TestStruct";
assert( isStringType(t) );
Is anything like this possible?
The goal is to identify whether a string represents a custom type within
a package. I'm also trying to iterate over all modules within the
package to get the struct name. However, that seems like a struggle...
Any ideas?..
In order to do this, the list of types must be stored somewhere to
compare with at runtime.
At this time, this is not done. You could potentially do this with the
RTInfo template, but it would have to be part of a custom druntime.
-Steve
Check whether string value represents a type
I'd love to check whether a string value is the name of a type at
run-time.
E.g.:
string a = "int";
string b = "im no type";
assert( isStringType(a) );
assert( !isStringType(b) );
or
struct TestStruct
{
int test;
}
string t = "TestStruct";
assert( isStringType(t) );
Is anything like this possible?
The goal is to identify whether a string represents a custom type
within a package. I'm also trying to iterate over all modules
within the package to get the struct name. However, that seems
like a struggle...
Any ideas?..
Re: How to replace pairs tags with regexp
On Friday, 21 July 2017 at 07:42:28 UTC, Suliman wrote:
On Friday, 21 July 2017 at 07:30:07 UTC, Antonio Corbi wrote:
On Friday, 21 July 2017 at 07:08:34 UTC, Suliman wrote:
On Friday, 21 July 2017 at 06:19:43 UTC, Suliman wrote:
There reason of issue above is spaces before "#".
What wrong with next regex https://dpaste.dzfl.pl/024a47ed2a56
I expect that it will select:
#Header
my header text
##SubHeader
my sub header text
Because: ^#{3}
Have you tried https://regex101.com/
It gives you results and explanations about your regex in
realtime.
A. Corbi
I tried. But I am getting different behavior in online editor
and in the code.
Could it be related to the regex's 'flavor' you are using?
A. Corbi
Re: How to replace pairs tags with regexp
On Friday, 21 July 2017 at 07:30:07 UTC, Antonio Corbi wrote:
On Friday, 21 July 2017 at 07:08:34 UTC, Suliman wrote:
On Friday, 21 July 2017 at 06:19:43 UTC, Suliman wrote:
There reason of issue above is spaces before "#".
What wrong with next regex https://dpaste.dzfl.pl/024a47ed2a56
I expect that it will select:
#Header
my header text
##SubHeader
my sub header text
Because: ^#{3}
Have you tried https://regex101.com/
It gives you results and explanations about your regex in
realtime.
A. Corbi
I tried. But I am getting different behavior in online editor and
in the code.
Re: How to replace pairs tags with regexp
On Friday, 21 July 2017 at 07:08:34 UTC, Suliman wrote:
On Friday, 21 July 2017 at 06:19:43 UTC, Suliman wrote:
There reason of issue above is spaces before "#".
What wrong with next regex https://dpaste.dzfl.pl/024a47ed2a56
I expect that it will select:
#Header
my header text
##SubHeader
my sub header text
Because: ^#{3}
Have you tried https://regex101.com/
It gives you results and explanations about your regex in
realtime.
A. Corbi
Re: How to replace pairs tags with regexp
On Friday, 21 July 2017 at 06:19:43 UTC, Suliman wrote:
There reason of issue above is spaces before "#".
What wrong with next regex https://dpaste.dzfl.pl/024a47ed2a56
I expect that it will select:
#Header
my header text
##SubHeader
my sub header text
Because: ^#{3}
Re: How to replace pairs tags with regexp
There reason of issue above is spaces before "#".
