Re: Getting the current datetime converted into a string for writing to stdout
On Sunday, March 30, 2014 08:25:42 Andre Artus wrote: Considering the international spread of D users I find it surprising that the date time formatting functions in phobos are not localizable. If could go back, there wouldn't even be anything to localize. toSimpleString is there because it was in Boost (and it's what toString uses), but by having _three_ different string functions for each type instead of just ISO and ISO Extended. So, that's arguably bad - certainly it overcomplicates things IMHO. And toSimpleString uses English names for the months which is _definitely_ bad, because it opens up the question of localization, which I see no reason to deal with in this context, especially because it opens up a huge can of worms. By sticking to ISO and ISO Extended, we'd be completely standards compliant and would avoid the whole localization issue entirely. As it stands, we just acknowledge that it's stupid that toSimpleString is there (thereby introducing the question of localization) and have agreed that localization is outside the scope of std.datetime. Unfortunately, removing toSimpleString would obviously break code, and changing toString to do the same as toISOExtString (as it probably should) could also break code if there's code in the wild which relies on the exact format of toString. So, we're kind of stuck. - Jonathan M Davis
Re: best D equivalent to C'stimeval
On Monday, March 31, 2014 05:09:22 ed wrote: Hi, Just wondering what the best replacement for C timeval is in D. I'm looking at std.datetime.SysTime, but std.datetime is huge so I'm not sure. If you want an overview of std.datetime, read http://dlang.org/intro-to-datetime.html But yes, SysTime would be what you'd want to use instead of a timeval. SysTime is intended for representing the time of the system, whereas DateTime, Date, or TimeOfDay relate to specifically to calendar time (they have no time zones and therefore cannot be tied to a unique point in time - e.g. a DateTime for 2014-03-30T12:00:00 could be one of over 24 different points in time, as it has no time zone to tie it down). SysTime holds its time internally in UTC and uses a TimeZone object to convert to to other time zones when required (e.g. when printing it out); it defaults to LocalTime, which represents the local time of your system. SysTime also has a function called toTimeVal for converting to a timeval if you need to pass it to C code. - Jonathan M Davis
Re: best D equivalent to C'stimeval
On Monday, 31 March 2014 at 06:25:40 UTC, Jonathan M Davis wrote: On Monday, March 31, 2014 05:09:22 ed wrote: Hi, Just wondering what the best replacement for C timeval is in D. I'm looking at std.datetime.SysTime, but std.datetime is huge so I'm not sure. If you want an overview of std.datetime, read http://dlang.org/intro-to-datetime.html But yes, SysTime would be what you'd want to use instead of a timeval. SysTime is intended for representing the time of the system, whereas DateTime, Date, or TimeOfDay relate to specifically to calendar time (they have no time zones and therefore cannot be tied to a unique point in time - e.g. a DateTime for 2014-03-30T12:00:00 could be one of over 24 different points in time, as it has no time zone to tie it down). SysTime holds its time internally in UTC and uses a TimeZone object to convert to to other time zones when required (e.g. when printing it out); it defaults to LocalTime, which represents the local time of your system. SysTime also has a function called toTimeVal for converting to a timeval if you need to pass it to C code. - Jonathan M Davis Great info, thank you. Cheers, ed
CTFE error, but I have no idea what it means.
I've been experimenting with D for a little while now. For the most part, I've been able get help from the language/library reference and IRC. But not this time. So here's the thing: http://dpaste.dzfl.pl/14680a8cec77 I've run it through Dustmite to reduce it to a smaller chunk of code. It runs just fine at runtime, but once I try to run parseTemplate during compile time/CTFE, it fails with this error: /d815/f521.d(37): called from here: this.parser.parse() /d815/f521.d(77): called from here: parseTemplate(child2.html, genFileTable()) dmd: statement.c:293: ErrorStatement::ErrorStatement(): Assertion `global.gaggedErrors || global.errors' failed. Usually when running into CTFE limitations, I've been able to understand what I'm doing wrong from the error messages, but this one doesn't make any sense to me. I hope someone with more D experience can tell me what's going on here, and how to fix it. Thanks, Olav.
Re: CTFE error, but I have no idea what it means.
Olav Lindekleiv: I hope someone with more D experience can tell me what's going on here, and how to fix it. It's a compiler bug. I suggest to minimize manually the example code as much as possible, and then add it to Bugzilla. Bye, bearophile
Re: CTFE error, but I have no idea what it means.
On Monday, 31 March 2014 at 11:02:24 UTC, bearophile wrote:
Olav Lindekleiv:
I hope someone with more D experience can tell me what's going
on here, and how to fix it.
It's a compiler bug. I suggest to minimize manually the example
code as much as possible, and then add it to Bugzilla.
Bye,
bearophile
I'm now down to 13 lines: http://dpaste.dzfl.pl/bbc84226a558
And it's the while(){} that causes the compiler to crash. It
isn't just , but any string. I'll create an issue on Bugzilla
for this.
Re: CTFE error, but I have no idea what it means.
Here's the issue:
http://d.puremagic.com/issues/show_bug.cgi?id=12498
Please ignore the last example above, and look at the one in
Bugzilla.
On Monday, 31 March 2014 at 11:08:18 UTC, Olav Lindekleiv wrote:
On Monday, 31 March 2014 at 11:02:24 UTC, bearophile wrote:
Olav Lindekleiv:
I hope someone with more D experience can tell me what's
going on here, and how to fix it.
It's a compiler bug. I suggest to minimize manually the
example code as much as possible, and then add it to Bugzilla.
Bye,
bearophile
I'm now down to 13 lines: http://dpaste.dzfl.pl/bbc84226a558
And it's the while(){} that causes the compiler to crash. It
isn't just , but any string. I'll create an issue on Bugzilla
for this.
Re: Does anyone have an example of use of core.sync.Condition
On Sun, 30 Mar 2014 12:09:35 -0400, Matt webwra...@fastmail.fm wrote: I have little experience in multi-threading programming, and was digging into std.concurrency, but I don't really understand the Condition class as it was used there. Could someone provide a bare-bones use of this class? I would be much obliged, thanks. Google thread condition variable. It's a very well-known pattern. -Steve
Re: Avoiding Range Checks in Slice Expressions
On Sun, 30 Mar 2014 15:40:43 -0400, Nordlöw per.nord...@gmail.com wrote: Does DMD currently avoid range checks in array slice expressions such as f(x[0..$/2]) f(x[$/2..$]) typically found in divide-and-conquer algorithms such as quicksort? If they are range-checked, it would be a good addition to the optimizer to remove them. My guess is that it is range-checked. If not, what would it require to implement it? As a hack, you can use the pointer, which will not be range checked: f(x.ptr[0..x.length/2]) // note you can't use $ because the pointer doesn't have length f(x.ptr[x.length/2..x.length]) -Steve
Re: Getting the current datetime converted into a string for writing to stdout
On Sunday, 30 March 2014 at 08:25:43 UTC, Andre Artus wrote: Considering the international spread of D users I find it surprising that the date time formatting functions in phobos are not localizable. Formatting should confined to presentation tier: GUI controls, web page generation and must not escape it the rest of code, localized formatting freely used in the whole codebase is a bad idea. Console output is often implied to be technical and even machine-readable, it's a bad idea to localize it. Deep integration of localization in e.g. .net causes lots of pain, the deeper it is, the more pain in the ass it causes, to the point of throwing exceptions with machine-translated error messages.
Re: destructor, postblit constructor --- force calling always
Am 31.03.2014 08:06, schrieb monarch_dodra: On Monday, 31 March 2014 at 01:03:22 UTC, Carl Sturtivant wrote: What about destructors, are they always called, or is this another optimization if the struct is in it's default .init state? In any case, there should be 1 destructor call for every object you declared. Except for thing on the heap. Those are just collected, not destroyed :/ The destructor is always called. There is never a instance that gets destroyed without the destructor beeing called. It can happen however that the destructor gets called on a .init state. This happens for example if you use std.algorithm.move. To be fully correct your struct should handle the .init state in the destructor (or assert at least so you can find and fix those occurences). Kind Regards Benjamin Thaut
Re: Parsing
Am Mon, 31 Mar 2014 04:06:38 + schrieb Joel joel...@gmail.com: I've got a program that uses user input, but I'm having trouble with it. Here's an example, the unenclosed numbers (1 2 3 in example) add entries: 0 Achievement 1 2 3 cWon! st4 5 6 - user input (create 3 entries all with st4 5 6) 0 Achievement 1 house [4, 5, 6] 2 rock [4, 5, 6] 3 mouse [4, 5, 6] cmud - user input 0 Achievement 1 house [4, 5, 6] mud 2 rock [4, 5, 6] mud 3 mouse [4, 5, 6] mud So add the entries and while they are still hot, you can edit them. I don't know if this an impossible ask for help, but I though I might get some help. I'll keep going over my code to work it out. Thanks. So what is the question? -- Marco
Re: best D equivalent to C'stimeval
Am Mon, 31 Mar 2014 05:09:22 + schrieb ed sillymong...@gmail.com: Hi, Just wondering what the best replacement for C timeval is in D. I'm looking at std.datetime.SysTime, but std.datetime is huge so I'm not sure. Thanks, ed If you just need to time something, TickDuration from core.time is an efficient cross-platform timer. auto t1 = TickDuration.currentSystemTick; ... auto t2 = TickDuration.currentSystemTick; writefln(Took %s ms, (t2-t1).msecs); -- Marco
How to foreach over a DList?
I am trying to foreach over a std.container.DList but it isn't working. I have tried the following code: https://gist.github.com/Binero/f30e56351baf05f1a2ec I am getting the following errors: /usr/include/dlang/dmd/std/container.d(1925): Error: template std.container.DList!ubyte.DList.insertBeforeNode cannot deduce function from argument types !()(typeof(null), int), candidates are: /usr/include/dlang/dmd/std/container.d(2096): std.container.DList!ubyte.DList.insertBeforeNode(Stuff)(Node* n, Stuff stuff) if (isInputRange!Stuff isImplicitlyConvertible!(ElementType!Stuff, T)) /usr/include/dlang/dmd/std/container.d(2155): std.container.DList!ubyte.DList.insertBeforeNode(Stuff)(Node* n, Stuff stuff) if (isImplicitlyConvertible!(Stuff, T)) source/app.d(7): Error: template instance std.container.DList!ubyte.DList.insertBack!int error instantiating source/app.d(11): Error: invalid foreach aggregate list1
Re: How to foreach over a DList?
On Mon, Mar 31, 2014 at 05:50:16PM +, Jeroen Bollen wrote:
I am trying to foreach over a std.container.DList but it isn't working. I
have tried the following code:
[...]
Maybe try using opSlice:
DList myList;
foreach (e; myList[]) { ... }
?
T
--
Three out of two people have difficulties with fractions. -- Dirk Eddelbuettel
Getting the current datetime converted into a string for writing to stdout
I've been reading through and trying various code fragments to pull the system date/time in and format it as a string for display on the console. I only need it down to the second and from my current machine so I don't need to use any of the more accurate clocks used for benchmarking right now. All the examples seem to be setting the date or date time to some predetermined value instead of pulling it from the system. It seems like this would be a very common function to use so I know I must be making this a lot harder than it really is. Oh and before I forget I'd like to thank everybody on the forum for their great support. I'm still a newbie at D. I've bought the book. I've watched the YouTube videos and now I'm starting to get a lot more comfortable with the code but it feels like it's going to take me some time to figure out the tricks for using all the library functions. I started out trying to use strings for everything but quickly found that my code is doing a lot of string modification concatenation and I had to switch to char[] instead to get around the immutability but now a lot of the library functions use the string data type so I am having to figure out how to convert between back and forth between all the different datatypes. It would be nice if all the primitive datatypes had a consistent toString cast or function but since I'm not seeing those I guess writeFormatted must be the preferred way of getting values into string format.
Re: Getting the current datetime converted into a string for writing to stdout
On Saturday, 29 March 2014 at 05:01:14 UTC, Gary Miller wrote:
I've been reading through and trying various code fragments to
pull the system date/time in and format it as a string for
display on the console.
I only need it down to the second and from my current machine
so I don't need to use any of the more accurate clocks used for
benchmarking right now.
This is the easiest way i know.
import std.stdio;
import std.datetime;
void main(string[] args)
{
writeln(Clock.currTime.toLocalTime.toSimpleString);
}
It would be nice if all the primitive datatypes had a
consistent toString cast or function but since I'm not seeing
those I guess writeFormatted must be the preferred way of
getting values into string format.
See std.conv and the 'to' function.
data.to!(string)
data.to!(int)
etc...
http://dlang.org/phobos/std_conv.html#.to
Re: Getting the current datetime converted into a string for writing to stdout
On Saturday, 29 March 2014 at 05:01:14 UTC, Gary Miller wrote: I've been reading through and trying various code fragments to pull the system date/time in and format it as a string for display on the console. Here's a good primer on the datetime module: http://dlang.org/intro-to-datetime.html
Re: How to foreach over a DList?
On Monday, 31 March 2014 at 19:26:23 UTC, Jeroen Bollen wrote:
On Monday, 31 March 2014 at 18:24:39 UTC, H. S. Teoh wrote:
On Mon, Mar 31, 2014 at 05:50:16PM +, Jeroen Bollen wrote:
I am trying to foreach over a std.container.DList but it
isn't working. I
have tried the following code:
[...]
Maybe try using opSlice:
DList myList;
foreach (e; myList[]) { ... }
?
T
Can you explain that syntax?
nvm figured it out;
Are constant DLists supposed to be un-foreach-able?
Error: mutable method std.container.DList!(ubyte).DList.opSlice
is not callable using a const object
template interface and delegates
Hi,
I'm new to D and played a bit with templates and delegates.
Now i discovered some behaviore that i don't understand.
Can somebody explain me why i get two different outputs?
import std.stdio;
interface A(T){
bool GetBool();
T getT();
}
class C:A!(double){
override bool GetBool(){
return false;
}
override double getT(){
return 1;
}
}
void mwriteln(T)( A!T delegate() dg){
writeln(dg().getT());
}
void main()
{
auto c = new C();
writeln(c.getT());
mwriteln!double({return new C();});
}
Re: How to set JSON_TYPE in 2.0.65
On 03/31/2014 02:59 PM, nrgyzer wrote: Hi guys, I updated my dmd version from 2.0.63 to 2.0.65 and having some trouble with my JSON-definitions. The code below worked in 2.0.63 but not in 2.0.65: JSONValue oJson = JSONValue(); oJson.type = JSON_TYPE.OBJECT; // FAILS oJson.object[myEntry] = JSONValue(); oJson.object[myEntry].type = JSON_TYPE.STRING; // FAILS oJSon.object[myEntry].str = MyText; Since the type property is a constant in 2.0.65, I've no idea how I can set the type for my JSON entries. I already tried the following: JSONValue oJson = JSONValue(JSON_TYPE.OBJECT); oJson.object[myEntry] = JSONValue(JSON_TYPE.STRING); oJSon.object[myEntry].str = MyText; But this gives me something like: JSONValue is not an object. Any idea how I can set the corresponding value type? I believe that this was simplified in recent releases, so one only needs to do the following: JSONValue oJson; oJson.object[myEntry] = MyText; (Untested but I believe this is how it's supposed to be now) -- Matt Soucy http://msoucy.me/
Re: How to foreach over a DList?
On Monday, 31 March 2014 at 18:24:39 UTC, H. S. Teoh wrote:
On Mon, Mar 31, 2014 at 05:50:16PM +, Jeroen Bollen wrote:
I am trying to foreach over a std.container.DList but it isn't
working. I
have tried the following code:
[...]
Maybe try using opSlice:
DList myList;
foreach (e; myList[]) { ... }
?
T
Can you explain that syntax?
Re: Parsing
Oops, the 'cWon!' shouldn't be there, I forgot to use it. On Monday, 31 March 2014 at 19:23:17 UTC, Joel wrote: On Monday, 31 March 2014 at 17:25:58 UTC, Marco Leise wrote: Am Mon, 31 Mar 2014 04:06:38 + schrieb Joel joel...@gmail.com: I've got a program that uses user input, but I'm having trouble with it. Here's an example, the unenclosed numbers (1 2 3 in example) add entries: 0 Achievement 1 2 3 cWon! st4 5 6 - user input (create 3 entries all with st4 5 6) 0 Achievement 1 house [4, 5, 6] 2 rock [4, 5, 6] 3 mouse [4, 5, 6] cmud - user input 0 Achievement 1 house [4, 5, 6] mud 2 rock [4, 5, 6] mud 3 mouse [4, 5, 6] mud So add the entries and while they are still hot, you can edit them. I don't know if this an impossible ask for help, but I though I might get some help. I'll keep going over my code to work it out. Thanks. So what is the question? Oh, how do I parse the example? So that entries are added and values are set. I'm not sure how to explain it.
Re: How to set JSON_TYPE in 2.0.65
On Mon, 31 Mar 2014 15:05:10 -0400, Matt Soucy wrote: I believe that this was simplified in recent releases, so one only needs to do the following: JSONValue oJson; oJson.object[myEntry] = MyText; (Untested but I believe this is how it's supposed to be now) That's correct, the type field has been moved to a read-only property. JSONValue should derive the appropriate type via assignment: JSONValue i = 2; // type == INTEGER JSONValue s = s; // type == STRING JSONValue a = [ JSONValue(1.0) ]; // type == ARRAY (of FLOAT) Note that you can also use the constructor (calls opAssign internally).
Re: How to foreach over a DList?
Still not working: https://gist.github.com/Binero/f30e56351baf05f1a2ec /usr/include/dlang/dmd/std/container.d(1925): Error: template std.container.DList!ubyte.DList.insertBeforeNode cannot deduce function from argument types !()(typeof(null), int), candidates are: /usr/include/dlang/dmd/std/container.d(2096): std.container.DList!ubyte.DList.insertBeforeNode(Stuff)(Node* n, Stuff stuff) if (isInputRange!Stuff isImplicitlyConvertible!(ElementType!Stuff, T)) /usr/include/dlang/dmd/std/container.d(2155): std.container.DList!ubyte.DList.insertBeforeNode(Stuff)(Node* n, Stuff stuff) if (isImplicitlyConvertible!(Stuff, T)) source/app.d(7): Error: template instance std.container.DList!ubyte.DList.insertBack!int error instantiating source/app.d(11): Error: need upper and lower bound to slice pointer
How to set JSON_TYPE in 2.0.65
Hi guys, I updated my dmd version from 2.0.63 to 2.0.65 and having some trouble with my JSON-definitions. The code below worked in 2.0.63 but not in 2.0.65: JSONValue oJson = JSONValue(); oJson.type = JSON_TYPE.OBJECT; // FAILS oJson.object[myEntry] = JSONValue(); oJson.object[myEntry].type = JSON_TYPE.STRING; // FAILS oJSon.object[myEntry].str = MyText; Since the type property is a constant in 2.0.65, I've no idea how I can set the type for my JSON entries. I already tried the following: JSONValue oJson = JSONValue(JSON_TYPE.OBJECT); oJson.object[myEntry] = JSONValue(JSON_TYPE.STRING); oJSon.object[myEntry].str = MyText; But this gives me something like: JSONValue is not an object. Any idea how I can set the corresponding value type?
Re: Parsing
On Monday, 31 March 2014 at 17:25:58 UTC, Marco Leise wrote: Am Mon, 31 Mar 2014 04:06:38 + schrieb Joel joel...@gmail.com: I've got a program that uses user input, but I'm having trouble with it. Here's an example, the unenclosed numbers (1 2 3 in example) add entries: 0 Achievement 1 2 3 cWon! st4 5 6 - user input (create 3 entries all with st4 5 6) 0 Achievement 1 house [4, 5, 6] 2 rock [4, 5, 6] 3 mouse [4, 5, 6] cmud - user input 0 Achievement 1 house [4, 5, 6] mud 2 rock [4, 5, 6] mud 3 mouse [4, 5, 6] mud So add the entries and while they are still hot, you can edit them. I don't know if this an impossible ask for help, but I though I might get some help. I'll keep going over my code to work it out. Thanks. So what is the question? Oh, how do I parse the example? So that entries are added and values are set. I'm not sure how to explain it.
Re: Avoiding Range Checks in Slice Expressions
If they are range-checked, it would be a good addition to the optimizer to remove them. My guess is that it is range-checked. $/n is of course always within range if n is positive integer = 1. But what about in the general indexing/slicing case? In that case it would be useful if we could reuse value range propagation (VRP) in DMD, to figure out which other expressions that don't need range checking.
Re: template interface and delegates
On Mon, 31 Mar 2014 18:58:30 +, anonymous wrote:
Hi,
I'm new to D and played a bit with templates and delegates.
Now i discovered some behaviore that i don't understand. Can somebody
explain me why i get two different outputs?
import std.stdio;
interface A(T){
bool GetBool();
T getT();
}
class C:A!(double){
override bool GetBool(){
return false;
}
override double getT(){
return 1;
}
}
void mwriteln(T)( A!T delegate() dg){
writeln(dg().getT());
}
void main()
{
auto c = new C(); writeln(c.getT()); mwriteln!double({return new
C();});
}
Looks like a bug. Here's a cleaned-up test case:
---
interface A(T)
{
T getT();
}
class C : A!double
{
double getT(){ return 1; }
}
void mwriteln(T)(A!T delegate() dg)
{
import std.stdio;
auto a = dg();
writeln(Checkpoint 1);
assert(a !is null);
writeln(a);
writeln(Checkpoint 2);
}
void main()
{
import std.traits;
static assert(isImplicitlyConvertible!(C, A!double));
mwriteln!double({return new C();});
}
---
Backtrace:
---
Program received signal SIGSEGV, Segmentation fault.
#0 0x0042ac8c in _d_interface_cast ()
#1 0x00427ec6 in
std.format.__T11formatValueTS3std5stdio4File17LockingTextWriterTC4test8__T1ATdZ1ATaZ.formatValue
() ()
#2 0x00427e23 in
std.format.__T13formatGenericTS3std5stdio4File17LockingTextWriterTC4test8__T1ATdZ1ATaZ.formatGeneric
() ()
#3 0x00427d29 in
std.format.__T14formattedWriteTS3std5stdio4File17LockingTextWriterTaTC4test8__T1ATdZ1AZ.formattedWrite
() ()
#4 0x00427871 in
std.stdio.File.__T5writeTC4test8__T1ATdZ1ATaZ.write() ()
#5 0x004277d5 in std.stdio.__T7writelnTC4test8__T1ATdZ1AZ.writeln
() ()
#6 0x0042771f in test.__T8mwritelnTdZ.mwriteln() ()
#7 0x004276a9 in D main ()
#8 0x0042b61c in rt.dmain2._d_run_main() ()
#9 0x0042b576 in rt.dmain2._d_run_main() ()
#10 0x0042b5dc in rt.dmain2._d_run_main() ()
#11 0x0042b576 in rt.dmain2._d_run_main() ()
#12 0x0042b4f7 in _d_run_main ()
#13 0x00429c5f in main ()
---
Re: Avoiding Range Checks in Slice Expressions
If not, what would it require to implement it? That would be an interesting task to fix :) DMD source references anyone?
tuple (TypeTuple kind) multi-initialization. Actually documented?
If you declare an instance of a tuple, eg TypeTuple!(int, int, int), you can initialize all members from a single argument. EG: TypeTuple!(int, int, int) a = 5; bearophile made a suggestion that we should deprecate this. https://d.puremagic.com/issues/show_bug.cgi?id=6367 I'd like to know if this behavior even documented at all, or kind of just happens to work. In particular, it doesn't work in CTFE at all: https://d.puremagic.com/issues/show_bug.cgi?id=12499 I'd like to ask the spec guru's to know which direction to take in dealing with both these issues.
Re: template interface and delegates
On Mon, 31 Mar 2014 14:58:30 -0400, anonymous n...@trash-mail.com wrote:
Hi,
I'm new to D and played a bit with templates and delegates.
Now i discovered some behaviore that i don't understand.
Can somebody explain me why i get two different outputs?
import std.stdio;
interface A(T){
bool GetBool();
T getT();
}
class C:A!(double){
override bool GetBool(){
return false;
}
override double getT(){
return 1;
}
}
void mwriteln(T)( A!T delegate() dg){
writeln(dg().getT());
}
void main()
{
auto c = new C();
writeln(c.getT());
mwriteln!double({return new C();});
}
This is definitely a bug.
Reduced case:
import std.stdio;
interface A{
void foo();
}
class C:A{
override void foo(){
writeln(here);
}
}
void x( A delegate() dg){
dg().foo();
}
void main()
{
A c = new C;
c.foo(); // prints here
x({A a = new C; return a;}); // prints here
x({return new C;}); // does not print
}
This is really an issue with delegate return type inferrence not working
properly.
-Steve
Re: tuple (TypeTuple kind) multi-initialization. Actually documented?
monarch_dodra: bearophile made a suggestion that we should deprecate this. https://d.puremagic.com/issues/show_bug.cgi?id=6367 It goes against the idea of tuple. No language that I know (Haskell, Rust, F#, Python, and more) that has tuples supports the initialization of a n-tuple with a scalar value. It's sloppy. And sloppy designs usually find a way to bite your rump later. Bye, bearophile
Re: tuple (TypeTuple kind) multi-initialization. Actually documented?
No language that I know (Haskell, Rust, F#, Python, and more) that has tuples supports the initialization of a n-tuple with a scalar value. In Python there is a way to build a n-tuple from a 1-tuple, but the seed is not a scalar, and this is an explicit syntax: (5,) * 3 (5, 5, 5) Bye, bearophile
Re: tuple (TypeTuple kind) multi-initialization. Actually documented?
On Monday, 31 March 2014 at 21:05:11 UTC, bearophile wrote: monarch_dodra: bearophile made a suggestion that we should deprecate this. https://d.puremagic.com/issues/show_bug.cgi?id=6367 It goes against the idea of tuple. No language that I know (Haskell, Rust, F#, Python, and more) that has tuples supports the initialization of a n-tuple with a scalar value. It's sloppy. And sloppy designs usually find a way to bite your rump later. Yes, but at this point, I (we?) don't even know if it's intended behavior to begin with. If it was an accident it worked to begin with, then it's fate should be sealed pretty fast. The fact that CTFE doesn't seem to work with it seems (to me) an indication of that.
Re: How to foreach over a DList?
On Mon, Mar 31, 2014 at 07:30:11PM +, Jeroen Bollen wrote:
On Monday, 31 March 2014 at 19:26:23 UTC, Jeroen Bollen wrote:
On Monday, 31 March 2014 at 18:24:39 UTC, H. S. Teoh wrote:
On Mon, Mar 31, 2014 at 05:50:16PM +, Jeroen Bollen wrote:
I am trying to foreach over a std.container.DList but it isn't
working. I
have tried the following code:
[...]
Maybe try using opSlice:
DList myList;
foreach (e; myList[]) { ... }
?
T
Can you explain that syntax?
nvm figured it out;
Are constant DLists supposed to be un-foreach-able?
Error: mutable method std.container.DList!(ubyte).DList.opSlice is not
callable using a const object
Argh, why is opSlice non-const? :-( Please file a bug.
Not sure what you can do in the meantime... probably cast away const? Or
avoid using const for containers if you can. The last time I tried that,
I got stuck in a quagmire of partially-implemented const support with no
way out of the mess, and I decided that non-const is less painful to
work with. :-/
T
--
English is useful because it is a mess. Since English is a mess, it maps well
onto the problem space, which is also a mess, which we call reality. Similarly,
Perl was designed to be a mess, though in the nicests of all possible ways. --
Larry Wall
Re: How to foreach over a DList?
On 03/31/2014 10:50 AM, Jeroen Bollen wrote:
I am trying to foreach over a std.container.DList but it isn't working.
I have tried the following code:
https://gist.github.com/Binero/f30e56351baf05f1a2ec
I am getting the following errors:
/usr/include/dlang/dmd/std/container.d(1925): Error: template
std.container.DList!ubyte.DList.insertBeforeNode cannot deduce function
from argument types !()(typeof(null), int), candidates are:
/usr/include/dlang/dmd/std/container.d(2096):
std.container.DList!ubyte.DList.insertBeforeNode(Stuff)(Node* n, Stuff
stuff) if (isInputRange!Stuff
isImplicitlyConvertible!(ElementType!Stuff, T))
/usr/include/dlang/dmd/std/container.d(2155):
std.container.DList!ubyte.DList.insertBeforeNode(Stuff)(Node* n, Stuff
stuff) if (isImplicitlyConvertible!(Stuff, T))
source/app.d(7): Error: template instance
std.container.DList!ubyte.DList.insertBack!int error instantiating
source/app.d(11): Error: invalid foreach aggregate list1
Some notes:
1) DList is a struct. So, there is no need for 'new'. However, new is
not an error but then the ~= syntax below cannot work on list1 without
dereferencing. (You did not use ~=, I just liked it. :) )
(*list1) ~= cast(ubyte)3;// would work
2) For the same reason, list1[] becomes plain array slicing and the
compiler is looking for upper and lower bound to slice pointer. This
would work:
(*list1)[]
3) 1, 2, and 3 are ints. So, I had to cast them.
import std.container;
import std.stdio;
void main()
{
auto list1 = DList!ubyte();
list1.insertBack(cast(ubyte)1);
list1.insertBack(cast(ubyte)2);
list1 ~= cast(ubyte)3;// alternative syntax
foreach(ubyte item; list1[]) {
writeln(item);
}
}
Ali
Re: How to foreach over a DList?
On Monday, 31 March 2014 at 21:41:16 UTC, H. S. Teoh wrote: Argh, why is opSlice non-const? :-( Please file a bug. If opSlice was const, then you'd get a const slice, with const reference. You wouldn't even be able to iterate on it. With some extra code, you could create some sort of slice of immutable type, but you'd still only be able to get const items. We *could* add a const *overload* but... Or avoid using const for containers if you can. That. D's turtles all the way down const doesn't work like C++'s head only const. As a general rule, don't use too much const in D, *especially* for containers-like objects... At this point, adding a const overload would be nothing more that a still unusable mess, with extra maintenance overhead.
Trying Multiple Aggregate reduce
I'm trying to figure out how to use reduce with multiply funs.
Here's my try on minmaxElement:
import std.typecons: tuple;
/** Returns: Tuple of Minmum and Maximum Element in X. */
auto minmaxElement(alias F = min, alias G = max, R)(in R range)
@safe pure nothrow if (isInputRange!R)
{
return reduce!(F, G)(tuple(ElementType!R.max,
ElementType!R.min), range);
}
unittest { assert([1, 2, 3].minmaxElement == tuple(1, 3)); }
which errors as
/home/per/opt/x86_64-unknown-linux-gnu/dmd/bin/../include/d2/std/algorithm.d(774,29):
Error: can only initialize const member _expand_field_0 inside
constructor
/home/per/opt/x86_64-unknown-linux-gnu/dmd/bin/../include/d2/std/algorithm.d(774,29):
Error: can only initialize const member _expand_field_1 inside
constructor
algorithm_ex.d(157,25): Error: template instance
std.algorithm.reduce!(min, max).reduce!(Tuple!(const(int),
const(int)), const(int)[]) error instantiating
algorithm_ex.d(160,28):instantiated from here:
minmaxElement!(min, max, const(int)[])
If I replace ElementType!R.min and ElementType!R.max with a
values, say 0 and 1 it compiles. What is going on here?
This seems related:
http://forum.dlang.org/thread/bug-1040...@http.d.puremagic.com/issues/
Re: How to foreach over a DList?
On 31-3-2014 19:50, Jeroen Bollen wrote: I am trying to foreach over a std.container.DList but it isn't working. I have tried the following code: https://gist.github.com/Binero/f30e56351baf05f1a2ec I am getting the following errors: /usr/include/dlang/dmd/std/container.d(1925): Error: template std.container.DList!ubyte.DList.insertBeforeNode cannot deduce function from argument types !()(typeof(null), int), candidates are: /usr/include/dlang/dmd/std/container.d(2096): std.container.DList!ubyte.DList.insertBeforeNode(Stuff)(Node* n, Stuff stuff) if (isInputRange!Stuff isImplicitlyConvertible!(ElementType!Stuff, T)) /usr/include/dlang/dmd/std/container.d(2155): std.container.DList!ubyte.DList.insertBeforeNode(Stuff)(Node* n, Stuff stuff) if (isImplicitlyConvertible!(Stuff, T)) source/app.d(7): Error: template instance std.container.DList!ubyte.DList.insertBack!int error instantiating source/app.d(11): Error: invalid foreach aggregate list1 http://rosettacode.org/wiki/Strand_sort#D
Re: Trying Multiple Aggregate reduce
Nordlöw:
I'm trying to figure out how to use reduce with multiply funs.
import std.algorithm: min, max, reduce;
import std.typecons: tuple, Unqual;
import std.range: isInputRange, ElementType;
/// Returns: Tuple of Minmum and Maximum Element in X.
auto minMax(alias F = min, alias G = max, R)(in R range)
@safe pure nothrow if (isInputRange!R) {
return reduce!(F, G)(tuple(Unqual!(ElementType!R).max,
Unqual!(ElementType!R).min),
range);
}
unittest {
assert([1, 2, 3].minMax == tuple(1, 3));
}
void main() {}
If I replace ElementType!R.min and ElementType!R.max with a
values, say 0 and 1 it compiles. What is going on here?
This seems related:
http://forum.dlang.org/thread/bug-1040...@http.d.puremagic.com/issues/
You can't use reduce with a const seed.
Bye,
bearophile
Re: Trying Multiple Aggregate reduce
On 03/31/2014 03:13 PM, bearophile wrote:
Nordlöw:
I'm trying to figure out how to use reduce with multiply funs.
Could someone please check the following. It looks like a compiler bug
on git head (DMD64 D Compiler v2.066-devel-75159e4):
import std.algorithm;
int foo(int value)
{
return value;
}
void main()
{
reduce!(foo, foo)(tuple(0, 0), [ 1 ]);
}
statement.c:274: ErrorStatement::ErrorStatement(): Assertion
`global.gaggedErrors || global.errors' failed.
Ali
Re: Trying Multiple Aggregate reduce
You can't use reduce with a const seed. This, surely, must be a compiler bug right? /Per
Re: How to foreach over a DList?
On Monday, 31 March 2014 at 21:55:03 UTC, monarch_dodra wrote: If opSlice was const, then you'd get a const slice, with const reference. You wouldn't even be able to iterate on it. const opSlice does not mean it returns a const(Range). With some extra code, you could create some sort of slice of immutable type, but you'd still only be able to get const items. Iterating over const items is the goal. We *could* add a const *overload* but... Or avoid using const for containers if you can. That. D's turtles all the way down const doesn't work like C++'s head only const. As a general rule, don't use too much const in D, *especially* for containers-like objects... At this point, adding a const overload would be nothing more that a still unusable mess, with extra maintenance overhead. Gotta disagree violently here. Asking for a const overload of opSlice isn't too much const. std.container is just in a sorry state regarding const compatibility. That can and should be fixed.
Re: Trying Multiple Aggregate reduce
Ali Çehreli: statement.c:274: ErrorStatement::ErrorStatement(): Assertion `global.gaggedErrors || global.errors' failed. It's a little compiler bug, that should go in Bugzilla (even if perhaps it was recently added). Bye, bearophile
Re: Trying Multiple Aggregate reduce
On 03/31/2014 04:01 PM, bearophile wrote: Ali Çehreli: statement.c:274: ErrorStatement::ErrorStatement(): Assertion `global.gaggedErrors || global.errors' failed. It's a little compiler bug, that should go in Bugzilla (even if perhaps it was recently added). https://d.puremagic.com/issues/show_bug.cgi?id=12501 Ali
Re: How to set JSON_TYPE in 2.0.65
On Monday, 31 March 2014 at 19:05:11 UTC, Matt Soucy wrote: On 03/31/2014 02:59 PM, nrgyzer wrote: Hi guys, I updated my dmd version from 2.0.63 to 2.0.65 and having some trouble with my JSON-definitions. The code below worked in 2.0.63 but not in 2.0.65: JSONValue oJson = JSONValue(); oJson.type = JSON_TYPE.OBJECT; // FAILS oJson.object[myEntry] = JSONValue(); oJson.object[myEntry].type = JSON_TYPE.STRING; // FAILS oJSon.object[myEntry].str = MyText; Since the type property is a constant in 2.0.65, I've no idea how I can set the type for my JSON entries. I already tried the following: JSONValue oJson = JSONValue(JSON_TYPE.OBJECT); oJson.object[myEntry] = JSONValue(JSON_TYPE.STRING); oJSon.object[myEntry].str = MyText; But this gives me something like: JSONValue is not an object. Any idea how I can set the corresponding value type? I believe that this was simplified in recent releases, so one only needs to do the following: JSONValue oJson; oJson.object[myEntry] = MyText; (Untested but I believe this is how it's supposed to be now) I believe for this case you would want this: JSONValue oJson = [ myEntry: MyText ];
Re: How to set JSON_TYPE in 2.0.65
I believe for this case you would want this: JSONValue oJson = [ myEntry: MyText ]; Yeah, and unfortunately, there is no that easy way to create an empty object type json value though. (Yes, I had a need for that). I needed to work around of that.
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Re: How to foreach over a DList?
On Mon, Mar 31, 2014 at 09:55:01PM +, monarch_dodra wrote: On Monday, 31 March 2014 at 21:41:16 UTC, H. S. Teoh wrote: Argh, why is opSlice non-const? :-( Please file a bug. If opSlice was const, then you'd get a const slice, with const reference. You wouldn't even be able to iterate on it. [...] Um... wat? I didn't say opSlice should return a const object (that would be ridiculous, as you point out). Rather, it should return a tail-const range that iterates over the const items in the const list. A const container that cannot be iterated over makes no sense at all. Iterating over something doesn't modify anything!! T -- Ruby is essentially Perl minus Wall.
Why is SysTime.init invalid?
Hi All,
I'm trying to use SysTime in a struct but I've noticed the
following:
(A) SysTime.init leads to a crash.
---
void main()
{
SysTime t;
writefln(t:%s, t);
}
% ./dtest
zsh: segmentation fault (core dumped) ./dtest
---
(B) Initialising a SysTime member directly fails
---
struct T
{
SysTime t=SysTime(0);
}
datetime.d (28538) Error: static variable _lowLock cannot be read
at compile time
---
Which means I have to provide a default ctor for my struct but do
not know how.
1. Is this by design or is it a bug?
2. Is there a way to provide a default struct ctor so I can init
the SysTime member?
If this is by design I don't think it should crash. A Date/Time
error is often something user code can safely recover from.
Thanks,
ed
Re: How to foreach over a DList?
Still no luck:
import std.container;
import std.stdio;
void main()
{
DList!ubyte list1 = DList!ubyte();
list1 ~= cast(ubyte) 1;
list1 ~= cast(ubyte) 2;
list1 ~= cast(ubyte) 3;
foreach(ubyte item; list1[]) {
writeln(item);
}
}
/usr/include/dlang/dmd/std/container.d(1874): Error: no property
'_first' for type 'ubyte'
/usr/include/dlang/dmd/std/container.d(1875): Error: no property
'_first' for type 'ubyte'
/usr/include/dlang/dmd/std/container.d(1875): Error: undefined
identifier rhs_, did you mean variable rhs?
source/app.d(7): Error: template instance
std.container.DList!ubyte.DList.opOpAssign!(~, ubyte) error
instantiating
source/app.d(7): Error: cannot append type ubyte to type
DList!ubyte
Re: Why is SysTime.init invalid?
OK, lazy me just read the std.satetime article again. It appears the design is for no invalid values and it is currently a known limitation due to CTFE. --- d_time_nan There is no equivalent. SysTime.init, which has a null TimeZone object, would be the closest, but once CTFE advances to the point that you can new up class objects with it, SysTime.init's timezone will be LocalTime, so don't rely on SysTime.init being invalid. std.datetime in general tries to avoid having any invalid states for any of its types. It's intended that creating such values be impossible. --- I would still like to know if there is a way around this so I can have my struct default init. Thanks, ed
Re: template interface and delegates
Ok, thought i did something wrong or got some wrong idea how it should work.
