Re: get number of items in DList
On Friday, 11 July 2014 at 14:48:26 UTC, H. S. Teoh via Digitalmars-d-learn wrote: On Fri, Jul 11, 2014 at 10:23:58AM -0300, Ary Borenszweig via Digitalmars-d-learn wrote: On 7/11/14, 4:46 AM, bearophile wrote: >pgtkda: > >>How can i get the number of items which are currently hold >>in a >>DList? > >Try (walkLength is from std.range): > >mydList[].walkLength > >Bye, >bearophile So the doubly linked list doesn't know it's length? That seems a bit inefficient... It should be relatively simple to write a wrapper that *does* keep track of length. The main problem, though, comes from list splicing: given two arbitrary points in the list, if you splice out the section of the list in between, there's no easy way to know how many items lie in between, so you'll have to walk the list to recompute the length then. Which sorta defeats the purpose of having a linked list. :) T I just wanted to use a DList because you can easily add new items. The walkLength property works perfectly, thank you.
Re: new properties for basic types
> Hmm.
> So how do I use stuff like this:
>
> template defaultInit(T)
> {
> static if (!is(typeof({ T v = void; })))// inout(U)
> @property T defaultInit(T v = T.init);
> else
> @property T defaultInit();
> }
>
> (this is from std.traits - ok, it's private, but anyway)
It should be invoked as `defaultInit!SomeType`
> Because I have seen nowhere anything like defaultInit!T (or T.defaultInit)
> and don't understand why here the attribute @property is used.
> Why does it make a difference, and how?
@property allows you to call a function without the parenthesis (), to
imitate a field in a struct or class.
In this particular case, I don't know what defaultInit is used for. It
seems to compile to a forward declaration of a function, but I don't
know what for.
I cannot find it on my copy of std.traits. What DMD version are you using?
Re: Compile time regex matching
On Mon, Jul 14, 2014 at 3:19 PM, Artur Skawina via Digitalmars-d-learn
wrote:
> On 07/14/14 13:42, Philippe Sigaud via Digitalmars-d-learn wrote:
>> asserts get an entire copy of the parse tree. It's a bit wasteful, but
>> using 'immutable' directly does not work here, but this is OK:
>>
>> enum res = MyRegex("abcabcdefFOOBAR"); // compile-time parsing
>> immutable result = res; // to avoid copying the enum value everywhere
>
>static immutable result = MyRegex("abcabcdefFOOBAR"); // compile-time
> parsing
Ah, static!
>
>> The static asserts then works (not the toString, though). Maybe
(snip diff)
I'll push that to the repo, thanks! I should sprinkle some const and
pure everywhere...
> [completely untested; just did a git clone and fixed the two
> errors the compiler was whining about. Hmm, did pegged get
> faster? Last time i tried (years ago) it was unusably slow;
> right now, compiling your example, i didn't notice the extra
> multi-second delay that was there then.]
It's still slower than some handcrafted parsers. At some time, I could
get it on par with std.regex (between 1.3 and 1.8 times slower), but
that meant losing some other properties. I have other parsing engines
partially implemented, with either a larger specter of grammars or
better speed (but not both!). I hope the coming holidays will let me
go back to it.
Re: is there a way to pause a program and resume with just a key press (or enter key)
On Tue, Jul 15, 2014 at 02:49:55AM +, WhatMeWorry via Digitalmars-d-learn
wrote:
> Sorry if this is an incredibly naive question.
>
> I prefer to pragmatically pause my programs periodically so that I can
> peruse output statements. Ideally, I'd like to continue by just hitting any
> old key. My feeble attempt below requires I enter at least one character and
> then the enter key.
>
> char ignore;
> writeln("Enter to continue");
> readf(" %s", &ignore);
>
> Is there a way to continue with any old key press? or just the enter key?
[...]
I don't know about Windows, but on Linux, you can just press ctrl-s and
ctrl-q to pause/resume the console. (This is a Linux terminal function,
not specific to D.)
T
--
Ruby is essentially Perl minus Wall.
is there a way to pause a program and resume with just a key press (or enter key)
Sorry if this is an incredibly naive question.
I prefer to pragmatically pause my programs periodically so that
I can peruse output statements. Ideally, I'd like to continue by
just hitting any old key. My feeble attempt below requires I
enter at least one character and then the enter key.
char ignore;
writeln("Enter to continue");
readf(" %s", &ignore);
Is there a way to continue with any old key press? or just the
enter key?
Thanks in advance.
Re: syntax for calling to with a getter as source argument
On Tuesday, 15 July 2014 at 00:19:15 UTC, Ali Çehreli wrote:
On 07/14/2014 05:10 PM, Ali Çehreli wrote:
> On 07/14/2014 04:04 PM, H. S. Teoh via Digitalmars-d-learn
wrote:
>
> > On Mon, Jul 14, 2014 at 09:12:30PM +, Klb via
Digitalmars-d-learn
> wrote:
> >> hello what is the right syntax for this:
> >>
> >>
> >> import std.stdio, std.conv;
> >>
> >> void main(string args[])
> >> {
> >> ubyte[3] src = [0, 1, 2];
> >> string trg = "";
> >>
> >> @property ubyte[3] srcAsProp(){return src;}
> >>
> >> // Error: template std.conv.to cannot deduce
function from
> argument types
> >> // !(string)(ubyte[3]), candidates are:
> >> trg = to!(string)(srcAsProp());
> >> }
> >>
> >>
> >> In a real-world application I'd use an intermediate value
but I'd like
> >> to know If it's possible...The strange fact is that it
doesn't trig an
> >> error if src is a dyn. array. (if you remove the 3 from
[3] then it
> >> passes).
> >
> > You need to slice the static array:
> >
> > trg = to!string(srcAsProp()[]);
>
> There seems to be an attempt in Phobos to support it without
needing an
> explicit slice.
>
> From std/phobos/conv.d:
I meant phobos/std/conv.d there.
> /*
>Converting static arrays forwards to their dynamic
counterparts.
> */
> T toImpl(T, S)(ref S s)
> if (isRawStaticArray!S)
Ok, I think I see now (after two minutes after posting it :) )
why it doesn't work. The overload above takes by-ref, which
does not bind to rvalues in D.
And the problem is, what srcAsProp() returns is an rvalue
because static arrays are value-types and they get copied.
> {
> return toImpl!(T, typeof(s[0])[])(s);
> }
>
> @safe pure nothrow unittest
> {
> char[4] test = ['a', 'b', 'c', 'd'];
> static assert(!isInputRange!(Unqual!(char[4])));
> assert(to!string(test) == test);
> }
>
> I don't know why that overload does not take care of OP's
case. (I am be
> completely off here. :) )
I hope I have it now. :p
Ali
Thanks for this accurate explanation. The problem is quite clear
now.
Re: syntax for calling to with a getter as source argument
On 07/14/2014 05:10 PM, Ali Çehreli wrote:
> On 07/14/2014 04:04 PM, H. S. Teoh via Digitalmars-d-learn wrote:
>
> > On Mon, Jul 14, 2014 at 09:12:30PM +, Klb via Digitalmars-d-learn
> wrote:
> >> hello what is the right syntax for this:
> >>
> >>
> >> import std.stdio, std.conv;
> >>
> >> void main(string args[])
> >> {
> >> ubyte[3] src = [0, 1, 2];
> >> string trg = "";
> >>
> >> @property ubyte[3] srcAsProp(){return src;}
> >>
> >> // Error: template std.conv.to cannot deduce function from
> argument types
> >> // !(string)(ubyte[3]), candidates are:
> >> trg = to!(string)(srcAsProp());
> >> }
> >>
> >>
> >> In a real-world application I'd use an intermediate value but I'd
like
> >> to know If it's possible...The strange fact is that it doesn't
trig an
> >> error if src is a dyn. array. (if you remove the 3 from [3] then it
> >> passes).
> >
> > You need to slice the static array:
> >
> > trg = to!string(srcAsProp()[]);
>
> There seems to be an attempt in Phobos to support it without needing an
> explicit slice.
>
> From std/phobos/conv.d:
I meant phobos/std/conv.d there.
> /*
>Converting static arrays forwards to their dynamic counterparts.
> */
> T toImpl(T, S)(ref S s)
> if (isRawStaticArray!S)
Ok, I think I see now (after two minutes after posting it :) ) why it
doesn't work. The overload above takes by-ref, which does not bind to
rvalues in D.
And the problem is, what srcAsProp() returns is an rvalue because static
arrays are value-types and they get copied.
> {
> return toImpl!(T, typeof(s[0])[])(s);
> }
>
> @safe pure nothrow unittest
> {
> char[4] test = ['a', 'b', 'c', 'd'];
> static assert(!isInputRange!(Unqual!(char[4])));
> assert(to!string(test) == test);
> }
>
> I don't know why that overload does not take care of OP's case. (I am be
> completely off here. :) )
I hope I have it now. :p
Ali
Re: syntax for calling to with a getter as source argument
On 07/14/2014 04:04 PM, H. S. Teoh via Digitalmars-d-learn wrote:
> On Mon, Jul 14, 2014 at 09:12:30PM +, Klb via Digitalmars-d-learn
wrote:
>> hello what is the right syntax for this:
>>
>>
>> import std.stdio, std.conv;
>>
>> void main(string args[])
>> {
>> ubyte[3] src = [0, 1, 2];
>> string trg = "";
>>
>> @property ubyte[3] srcAsProp(){return src;}
>>
>> // Error: template std.conv.to cannot deduce function from
argument types
>> // !(string)(ubyte[3]), candidates are:
>> trg = to!(string)(srcAsProp());
>> }
>>
>>
>> In a real-world application I'd use an intermediate value but I'd like
>> to know If it's possible...The strange fact is that it doesn't trig an
>> error if src is a dyn. array. (if you remove the 3 from [3] then it
>> passes).
>
> You need to slice the static array:
>
>trg = to!string(srcAsProp()[]);
There seems to be an attempt in Phobos to support it without needing an
explicit slice.
From std/phobos/conv.d:
/*
Converting static arrays forwards to their dynamic counterparts.
*/
T toImpl(T, S)(ref S s)
if (isRawStaticArray!S)
{
return toImpl!(T, typeof(s[0])[])(s);
}
@safe pure nothrow unittest
{
char[4] test = ['a', 'b', 'c', 'd'];
static assert(!isInputRange!(Unqual!(char[4])));
assert(to!string(test) == test);
}
I don't know why that overload does not take care of OP's case. (I am be
completely off here. :) )
Ali
Re: Generating Strings with Random Contents
Nordlöw: https://github.com/nordlow/justd/blob/master/random_ex.d#L53 Isn't @trusted mostly for small parts of Phobos code? I suggest to avoid using @trusted in most cases. Bye, bearophile
Re: Generating Strings with Random Contents
On Monday, 14 July 2014 at 22:45:29 UTC, Nordlöw wrote: So I guess we need something more than just isValidCodePoint right? Here's a first try: https://github.com/nordlow/justd/blob/master/random_ex.d#L53
Re: Generating Strings with Random Contents
On Monday, 14 July 2014 at 22:32:25 UTC, bearophile wrote: Brad Anderson: Alternative: randomSample(lowercase, 10, lowercase.length).writeln; From randomSample docs: Selects a random subsample out of r, containing exactly n elements. The order of elements is the same as in the original range.< Bye, bearophile Hmm, good catch. Not the behavior I expected.
Re: syntax for calling to with a getter as source argument
On Mon, Jul 14, 2014 at 09:12:30PM +, Klb via Digitalmars-d-learn wrote:
> hello what is the right syntax for this:
>
>
> import std.stdio, std.conv;
>
> void main(string args[])
> {
> ubyte[3] src = [0, 1, 2];
> string trg = "";
>
> @property ubyte[3] srcAsProp(){return src;}
>
> // Error: template std.conv.to cannot deduce function from argument types
> // !(string)(ubyte[3]), candidates are:
> trg = to!(string)(srcAsProp());
> }
>
>
> In a real-world application I'd use an intermediate value but I'd like
> to know If it's possible...The strange fact is that it doesn't trig an
> error if src is a dyn. array. (if you remove the 3 from [3] then it
> passes).
You need to slice the static array:
trg = to!string(srcAsProp()[]);
Or, if you like to use UFCS (Uniform Function Call Syntax):
trg = srcAsProp()[].to!string;
You might want to file an enhancement request to improve the error
message, though -- it's not very helpful as it stands.
T
--
Trying to define yourself is like trying to bite your own teeth. -- Alan Watts
Re: Generating Strings with Random Contents
On Monday, 14 July 2014 at 22:39:15 UTC, bearophile wrote: Several combinations of unicode chars are not meaningful/valid (like pairs of ligatures). Any thing that has to work correctly with Unicode is complex. So I guess we need something more than just isValidCodePoint right?
Re: Generating Strings with Random Contents
On Monday, 14 July 2014 at 22:39:08 UTC, Nordlöw wrote:
might be were to start.
Is it really this simple?
bool isValidCodePoint(dchar c)
{
return c < 0xD800 || (c >= 0xE000 && c < 0x11);
}
Re: Generating Strings with Random Contents
Nordlöw: I believe defining a complete random sampling of all code units in dchar is a good start right? This can then be reused to lazily convert while filling in a string and wstring. Several combinations of unicode chars are not meaningful/valid (like pairs of ligatures). Any thing that has to work correctly with Unicode is complex. Bye, bearophile
Re: Generating Strings with Random Contents
Nordlöw: I was specifically interested in something that exercises (random samples) potentially _all_ code points for string, wstring and dstring (all code units that is). That's harder. Generating all uints and then testing if it's a Unicode dchar seems possible. Bye, bearophile
Re: Generating Strings with Random Contents
On Monday, 14 July 2014 at 22:35:59 UTC, Nordlöw wrote: On Monday, 14 July 2014 at 22:32:51 UTC, Nordlöw wrote: I believe defining a complete random sampling of all code units in dchar is a good start right? This can then be reused to lazily convert while filling in a string and wstring. isValidCodePoint() at http://dlang.org/phobos/std_encoding.html might be were to start.
Re: Generating Strings with Random Contents
On Monday, 14 July 2014 at 22:32:51 UTC, Nordlöw wrote: I believe defining a complete random sampling of all code units in dchar is a good start right? This can then be reused to lazily convert while filling in a string and wstring.
Re: Generating Strings with Random Contents
On Monday, 14 July 2014 at 22:21:36 UTC, bearophile wrote:
Nordlöw:
Is there a natural way of generating/filling a
string/wstring/dstring of a specific length with random
contents?
Do you mean something like this?
import std.stdio, std.random, std.ascii, std.range, std.conv;
string genRandomString(in size_t len) {
return len
.iota
.map!(_ => lowercase[uniform(0, $)])
.text;
}
void main() {
import std.stdio;
10.genRandomString.writeln;
}
Bye,
bearophile
I was specifically interested in something that exercises (random
samples) potentially _all_ code points for string, wstring and
dstring (all code units that is).
Re: Generating Strings with Random Contents
Brad Anderson: Alternative: randomSample(lowercase, 10, lowercase.length).writeln; From randomSample docs: Selects a random subsample out of r, containing exactly n elements. The order of elements is the same as in the original range.< Bye, bearophile
Re: DUB git master hang
On Monday, 14 July 2014 at 22:27:48 UTC, Nordlöw wrote: and then it hangs with same behaviour. It finally got through...hmm maybe I'm on a slow 3g-network currently...
Re: DUB git master hang
On Monday, 14 July 2014 at 22:10:01 UTC, Nordlöw wrote: On Monday, 14 July 2014 at 22:08:58 UTC, Nordlöw wrote: dub upgrade also hangs. also at 12 percent cpu usage. After removal of ~/.dub I did du[per:/home/per/justd] master(+13/-4,1) ± dub Fetching logger 0.1.0 (getting selected version)... Placing logger 0.1.0 to /home/per/.dub/packages/... Fetching ae-graphics 0.0.2 (getting selected version)... Placing ae-graphics 0.0.2 to /home/per/.dub/packages/... Fetching vibe-d ~master (getting selected version)... Placing vibe-d ~master to /home/per/.dub/packages/... Fetching libevent ~master (getting selected version)... Placing libevent ~master to /home/per/.dub/packages/... Fetching derelict-util 1.0.2 (getting selected version)... Placing derelict-util 1.0.2 to /home/per/.dub/packages/... Fetching derelict-assimp3 1.0.0 (getting selected version)... Placing derelict-assimp3 1.0.0 to /home/per/.dub/packages/... Fetching openssl ~master (getting selected version)... Placing openssl ~master to /home/per/.dub/packages/... Fetching libev ~master (getting selected version)... Placing libev ~master to /home/per/.dub/packages/... Fetching gfm ~master (getting selected version)... Placing gfm ~master to /home/per/.dub/packages/... Fetching derelict-fi 1.0.0 (getting selected version)... Placing derelict-fi 1.0.0 to /home/per/.dub/packages/... Fetching derelict-sdl2 1.2.3 (getting selected version)... Placing derelict-sdl2 1.2.3 to /home/per/.dub/packages/... Fetching derelict-enet 1.3.10 (getting selected version)... Placing derelict-enet 1.3.10 to /home/per/.dub/packages/... Fetching derelict-gl3 1.0.3 (getting selected version)... Placing derelict-gl3 1.0.3 to /home/per/.dub/packages/... and then it hangs with same behaviour.
Re: Generating Strings with Random Contents
On Monday, 14 July 2014 at 22:27:57 UTC, Brad Anderson wrote: Alternative: randomSample(lowercase, 10, lowercase.length).writeln; std.ascii should really be using std.encoding.AsciiString. Then that length wouldn't be necessary.
Re: Generating Strings with Random Contents
On Monday, 14 July 2014 at 22:21:36 UTC, bearophile wrote:
Nordlöw:
Is there a natural way of generating/filling a
string/wstring/dstring of a specific length with random
contents?
Do you mean something like this?
import std.stdio, std.random, std.ascii, std.range, std.conv;
string genRandomString(in size_t len) {
return len
.iota
.map!(_ => lowercase[uniform(0, $)])
.text;
}
void main() {
import std.stdio;
10.genRandomString.writeln;
}
Bye,
bearophile
Alternative:
randomSample(lowercase, 10, lowercase.length).writeln;
Re: Generating Strings with Random Contents
Nordlöw:
Is there a natural way of generating/filling a
string/wstring/dstring of a specific length with random
contents?
Do you mean something like this?
import std.stdio, std.random, std.ascii, std.range, std.conv;
string genRandomString(in size_t len) {
return len
.iota
.map!(_ => lowercase[uniform(0, $)])
.text;
}
void main() {
import std.stdio;
10.genRandomString.writeln;
}
Bye,
bearophile
Generating Strings with Random Contents
Is there a natural way of generating/filling a string/wstring/dstring of a specific length with random contents?
Re: DUB git master hang
On Monday, 14 July 2014 at 22:08:58 UTC, Nordlöw wrote: dub upgrade also hangs. also at 12 percent cpu usage.
Re: DUB git master hang
On Monday, 14 July 2014 at 21:50:51 UTC, Nordlöw wrote: My dub built from git master has suddenly started to hang on dub upgrade also hangs.
Re: Undo struct slicing by type-punning
On 07/14/2014 02:34 PM, ponce wrote: > On Monday, 14 July 2014 at 18:43:36 UTC, Ali Çehreli wrote: >> On 07/14/2014 10:35 AM, ponce wrote: >> >> > Ok, solved it, I just use pointer casts and it seems to work >> when the >> > struct is sliced. >> >> I think there is a terminology issue here. Slicing cannot be undone; >> once the object is sliced, the non-A parts are gone. >> > > Well they are not really gone if the struct is passed by-ref, Oh, it's not slicing in that case... but wait! There is a problem here. :) In C++, both structs and classes are value types and they both support inheritance. To observe slicing in C++, one needs pass-by-value and inheritance, which is available by structs and classes. In D, structs don't support inheritance and classes don't support pass-by-value. However... Enter 'alias this' and we have D's version of slicing. > you can recover the "gone" parts: http://dpaste.dzfl.pl/d64863fd4c6d Aggreed but in D's case the non-A parts are not gone; as long as A lives, we know that B is alive. This is different from C++ where due to the necessary pass-by-value, they are truly gone (the bits may still be there but a C++ code should not do as D does). Ali
Re: DUB git master hang
On Monday, 14 July 2014 at 21:47:20 UTC, Nordlöw wrote:
My dub built from git master has suddenly started to hang on
During hang:
- dub CPU system usage is about 12 percent
- No dmd process currently activate
- End of output from strace dub:
lstat("source/app.d", {st_mode=S_IFREG|0664, st_size=9211, ...})
= 0
lstat("src/", 0x7fff0b0672a0) = -1 ENOENT (No such file
or directory)
lstat("views", {st_mode=S_IFDIR|0775, st_size=0, ...}) = 0
lstat("source/", {st_mode=S_IFDIR|0775, st_size=22, ...}) = 0
lstat("source/app.d", {st_mode=S_IFREG|0664, st_size=9211, ...})
= 0
lstat("src/", 0x7fff0b0672a0) = -1 ENOENT (No such file
or directory)
lstat("views", {st_mode=S_IFDIR|0775, st_size=0, ...}) = 0
lstat("source/", {st_mode=S_IFDIR|0775, st_size=22, ...}) = 0
lstat("source/app.d", {st_mode=S_IFREG|0664, st_size=9211, ...})
= 0
lstat("src/", 0x7fff0b0672a0) = -1 ENOENT (No such file
or directory)
lstat("views", {st_mode=S_IFDIR|0775, st_size=0, ...}) = 0
lstat("source/", {st_mode=S_IFDIR|0775, st_size=22, ...}) = 0
lstat("source/app.d", {st_mode=S_IFREG|0664, st_size=9211, ...})
= 0
lstat("src/", 0x7fff0b0672a0) = -1 ENOENT (No such file
or directory)
lstat("views", {st_mode=S_IFDIR|0775, st_size=0, ...}) = 0
lstat("source/", {st_mode=S_IFDIR|0775, st_size=22, ...}) = 0
lstat("source/app.d", {st_mode=S_IFREG|0664, st_size=9211, ...})
= 0
lstat("src/", 0x7fff0b0672a0) = -1 ENOENT (No such file
or directory)
lstat("views", {st_mode=S_IFDIR|0775, st_size=0, ...}) = 0
lstat("source/", {st_mode=S_IFDIR|0775, st_size=22, ...}) = 0
lstat("source/app.d", {st_mode=S_IFREG|0664, st_size=9211, ...})
= 0
lstat("src/", 0x7fff0b0672a0) = -1 ENOENT (No such file
or directory)
lstat("views", {st_mode=S_IFDIR|0775, st_size=0, ...}) = 0
lstat("source/", {st_mode=S_IFDIR|0775, st_size=22, ...}) = 0
lstat("source/app.d", {st_mode=S_IFREG|0664, st_size=9211, ...})
= 0
lstat("src/", 0x7fff0b0672a0) = -1 ENOENT (No such file
or directory)
lstat("views", {st_mode=S_IFDIR|0775, st_size=0, ...}) = 0
lstat("source/", {st_mode=S_IFDIR|0775, st_size=22, ...}) = 0
lstat("source/app.d", {st_mode=S_IFREG|0664, st_size=9211, ...})
= 0
lstat("src/", 0x7fff0b0672a0) = -1 ENOENT (No such file
or directory)
lstat("views", {st_mode=S_IFDIR|0775, st_size=0, ...}) = 0
lstat("source/", {st_mode=S_IFDIR|0775, st_size=22, ...}) = 0
lstat("source/app.d", {st_mode=S_IFREG|0664, st_size=9211, ...})
= 0
lstat("src/", 0x7fff0b0672a0) = -1 ENOENT (No such file
or directory)
^R
--- SIGWINCH {si_signo=SIGWINCH, si_code=SI_KERNEL} ---
--- SIGWINCH {si_signo=SIGWINCH, si_code=SI_KERNEL} ---
DUB git master hang
My dub built from git master has suddenly started to hang on most commands in my project. What to do? Is there some cleanup I can try? /Per
Re: Undo struct slicing by type-punning
On Monday, 14 July 2014 at 18:43:36 UTC, Ali Çehreli wrote:
It is guaranteed by the language spec that yes, myFunction()
takes an A by reference. However, you can't know where that A
is coming from; so, the safety of that cast is up to you.
Consider:
void foo(A a) // <-- Already sliced
{
myFunction(a);// <-- Will perform invalid cast
}
Indeed, the code I port do that because struct have a type-tag.
Re: Undo struct slicing by type-punning
On Monday, 14 July 2014 at 18:43:36 UTC, Ali Çehreli wrote: On 07/14/2014 10:35 AM, ponce wrote: > Ok, solved it, I just use pointer casts and it seems to work when the > struct is sliced. I think there is a terminology issue here. Slicing cannot be undone; once the object is sliced, the non-A parts are gone. Well they are not really gone if the struct is passed by-ref, you can recover the "gone" parts: http://dpaste.dzfl.pl/d64863fd4c6d
Re: DMDScript
My idea is to use (at least test) DMDScript for server side JS. I don't mean to sound like a D-hater here, but V8 has had about 2 years more work on it than DMDScript. At one time they were. IIRC, quite close performance-wise but lots of work and support by Google have probably levered past the advantages of being coded in D. My 2c only.
syntax for calling to with a getter as source argument
hello what is the right syntax for this:
import std.stdio, std.conv;
void main(string args[])
{
ubyte[3] src = [0, 1, 2];
string trg = "";
@property ubyte[3] srcAsProp(){return src;}
// Error: template std.conv.to cannot deduce function from
argument types
// !(string)(ubyte[3]), candidates are:
trg = to!(string)(srcAsProp());
}
In a real-world application I'd use an intermediate value but I'd
like to know If it's possible...The strange fact is that it
doesn't trig an error if src is a dyn. array. (if you remove the
3 from [3] then it passes).
Re: reference to delegates and garbage collection
I'm just guessing, but it looks to me that the delegate's pointer might be on the stack there and isn't overwritten when the one function returns, so the gc still thinks there might be an active pointer to it.
Re: Undo struct slicing by type-punning
On 07/14/2014 10:35 AM, ponce wrote:
> Ok, solved it, I just use pointer casts and it seems to work when the
> struct is sliced.
I think there is a terminology issue here. Slicing cannot be undone;
once the object is sliced, the non-A parts are gone.
> On Monday, 14 July 2014 at 13:23:57 UTC, ponce wrote:
>> Hi,
>>
>> I am porting C++ code that undo "Object Slicing" by casting
>> const-references:
>> http://en.wikipedia.org/wiki/Object_slicing
>>
>>
>> My translation in D Code
>>
>>
>> struct A
>> {
>> // stuff
>> }
>>
>> struct B
>> {
>> A a;
>> alias a this;
>> // stuff
>> }
>>
>> void myFunction(ref const(A) a)
>> {
>> if ()
>> {
>> // here goes the converstion to a B reference
>> myFunction2(*cast(const(B)*)(&a)); // using pointer to do
>> type-punning
>> }
>> }
>>
>>
>>
>>
>> To do this, I need to by guaranteed an object passed through ref
>> const(A) is never, ever passed by value. Is it safe to assume?
It is guaranteed by the language spec that yes, myFunction() takes an A
by reference. However, you can't know where that A is coming from; so,
the safety of that cast is up to you. Consider:
void foo(A a) // <-- Already sliced
{
myFunction(a);// <-- Will perform invalid cast
}
Ali
reference to delegates and garbage collection
Hello everybody. I am new to D, and I am trying to familiarize
with all the new (to me) features.
I have a question about a strange behavior I cannot understand.
(In case it matters, I am using gdc 2.065 for Windows, but the
same happens with dmd).
Example code :
class A {
void delegate() del;
~this() { writeln("A Destructor called"); }
}
class B {
void fun() {}
}
A makeA() {
auto a = new A();
a.del = &(new B().fun);
return a;
}
void main() {
auto a = makeA();
/* Magic line goes here, see below */
a = null;
foreach(i; 0..10) {
writeln("Collecting");
GC.collect();
}
writeln("End");
}
If I run this code, the instance of A is of course collected at
the first call to GC.collect().
But if I call the delegate (i.e. a.del() ) in the "magic line",
the instance is not destroyed until the end of the main. If I
"wrap" the call to a.del() in another function or method, the
instance is collected.
Can somebody explain why this happens? Is it just a strangeness
of the GC? Does calling the delegate keep a reference to a in the
current scope? Am I going crazy? I spent about half an hour
looking for a non-existent memory leak in my program because of
this behavior, so I'd like to have an explanation.
Thanks in advance!
Re: Implement Interface "dynamically"
http://dlang.org/phobos/std_typecons.html#.BlackHole http://dlang.org/phobos/std_typecons.html#.WhiteHole http://dlang.org/phobos/std_typecons.html#.AutoImplement ?
Re: Implement Interface "dynamically"
There's some handy refection stuff in there too: https://github.com/nomad-software/dunit/blob/master/source/dunit/reflection.d
Re: Implement Interface "dynamically"
On Monday, 14 July 2014 at 14:45:01 UTC, Frustrated wrote: Is there a way to take an interface and implement it generically? e.g., All functions are implemented either as throw and/or return defaults and properties are implemented as getter/setters. This is for mocking up so I a simple way to create a class based off only the interface. Essentially something similar to whitehole and blackhole except properties are useable. In fact, I suppose it would be nice to have something analogous to them except properties are implemented. Then one could do Blackhole!(Bluehole!C) where Bluehole implements properties as getters and setters. You can maybe get some ideas from this mocking code i wrote: https://github.com/nomad-software/dunit/blob/master/source/dunit/mockable.d
Re: Undo struct slicing by type-punning
Ok, solved it, I just use pointer casts and it seems to work when
the struct is sliced.
On Monday, 14 July 2014 at 13:23:57 UTC, ponce wrote:
Hi,
I am porting C++ code that undo "Object Slicing" by casting
const-references:
http://en.wikipedia.org/wiki/Object_slicing
My translation in D Code
struct A
{
// stuff
}
struct B
{
A a;
alias a this;
// stuff
}
void myFunction(ref const(A) a)
{
if ()
{
// here goes the converstion to a B reference
myFunction2(*cast(const(B)*)(&a)); // using pointer to
do type-punning
}
}
To do this, I need to by guaranteed an object passed through
ref const(A) is never, ever passed by value. Is it safe to
assume?
Re: SImple C++ code to D
Alexandre:
void InjectData(T)(ref T BaseSrc, string data)
{
memcpy(&BaseSrc, data.ptr, data.length);
}
It's possible to improve this function ?
You can add some modifiers (like @nogc for dmd 2.066), and the
name of D functions starts with a lower case.
Bye,
bearophile
Re: SImple C++ code to D
void InjectData(T)(ref T BaseSrc, string data)
{
memcpy(&BaseSrc, data.ptr, data.length);
}
It's possible to improve this function ?
On Monday, 14 July 2014 at 15:45:19 UTC, bearophile wrote:
Alexandre:
Look the complete code:
https://gist.github.com/bencz/3576dfc8a217a34c05a9
I know, has several things that can be improved
memcpy(&dosh.e_magic, "MZ".ptr, 2);
memcpy(&peh.Signature, "PE\0\0".ptr, 4);
memcpy(scth[1].Name.ptr, ".idata".ptr, 6);
memcpy(scth[2].Name.ptr, ".data".ptr, 5);
memcpy(&image[0x428], x"3820".ptr, 2);
memcpy(&image[0x430], x"3820".ptr, 2);
memcpy(&image[0x43a], "printf".ptr, 6);
memcpy(&image[0x448], "msvcrt.dll".ptr, 10);
memcpy(&image[0x201], x"00304000".ptr, 4);
memcpy(&image[0x207], x"30204000".ptr, 4);
memcpy(&image[0x600], "hello\n".ptr, 6);
Instead of this very bug-prone code, write yourself a little
function to perform this more safely.
Bye,
bearophile
Re: SImple C++ code to D
Alexandre: Look the complete code: https://gist.github.com/bencz/3576dfc8a217a34c05a9 I know, has several things that can be improved memcpy(&dosh.e_magic, "MZ".ptr, 2); memcpy(&peh.Signature, "PE\0\0".ptr, 4); memcpy(scth[1].Name.ptr, ".idata".ptr, 6); memcpy(scth[2].Name.ptr, ".data".ptr, 5); memcpy(&image[0x428], x"3820".ptr, 2); memcpy(&image[0x430], x"3820".ptr, 2); memcpy(&image[0x43a], "printf".ptr, 6); memcpy(&image[0x448], "msvcrt.dll".ptr, 10); memcpy(&image[0x201], x"00304000".ptr, 4); memcpy(&image[0x207], x"30204000".ptr, 4); memcpy(&image[0x600], "hello\n".ptr, 6); Instead of this very bug-prone code, write yourself a little function to perform this more safely. Bye, bearophile
Re: SImple C++ code to D
Soory, I not understand, why lose the optlink ? Read the libs is simple, but, the linker do the brute force! On Monday, 14 July 2014 at 15:17:06 UTC, Jason King wrote: On Monday, 14 July 2014 at 14:50:36 UTC, Alexandre wrote: Yes yes, I did it, I used the anonymous type Look the complete code: https://gist.github.com/bencz/3576dfc8a217a34c05a9 I know, has several things that can be improved Now that you've done that, can you build us a linker that reads COFF libs so we can lose optlink:)
Re: SImple C++ code to D
On Monday, 14 July 2014 at 14:50:36 UTC, Alexandre wrote: Yes yes, I did it, I used the anonymous type Look the complete code: https://gist.github.com/bencz/3576dfc8a217a34c05a9 I know, has several things that can be improved Now that you've done that, can you build us a linker that reads COFF libs so we can lose optlink:)
Re: SImple C++ code to D
Yes yes, I did it, I used the anonymous type Look the complete code: https://gist.github.com/bencz/3576dfc8a217a34c05a9 I know, has several things that can be improved
Implement Interface "dynamically"
Is there a way to take an interface and implement it generically? e.g., All functions are implemented either as throw and/or return defaults and properties are implemented as getter/setters. This is for mocking up so I a simple way to create a class based off only the interface. Essentially something similar to whitehole and blackhole except properties are useable. In fact, I suppose it would be nice to have something analogous to them except properties are implemented. Then one could do Blackhole!(Bluehole!C) where Bluehole implements properties as getters and setters.
Re: SImple C++ code to D
Generally in D field names start with a lowercase (unless you need them with uppercase). And user defined type names start with an upper case. This is useful, because if you write: scth[0].Misc.virtualSize = 15; You see immediately that Misc is not a value but a type. So it can't work. Bye, bearophile
Re: SImple C++ code to D
Alexandre:
BYTE[8] Name;
Generally in D field names start with a lowercase (unless you
need them with uppercase).
Btw, my problem is, how to acess the union elements ?
I try this:
//...
scth[0].Misc.VirtualSize = 15;
//...
But, the compiler return that error:
main.d(151): Error: need 'this' for 'VirtualSize' of type 'uint'
The error message is not the best. It is saying you are not
accessing data, just its definition. So you need to instantiate
the union:
struct Foo {
ubyte[8] name;
union Bar {
ushort physicalAddress, virtualSize;
}
Bar b;
}
void main() {
Foo f;
f.b.physicalAddress = 10;
}
Or use an anonymous one:
struct Foo {
ubyte[8] name;
union {
ushort physicalAddress, virtualSize;
}
}
void main() {
Foo f;
f.physicalAddress = 10;
}
Bye,
bearophile
Re: SImple C++ code to D
bearophile, Thanks for all help!
As I said, I'm coming from C # and C + +, I need to learn
"tricks" of D language...
'm reading this book: http://ddili.org/ders/d.en/
I have a struct with union...
struct IMAGE_SECTION_HEADER
{
BYTE[8] Name;
union Misc
{
DWORD PhysicalAddress,
VirtualSize;
}
DWORD VirtualAddress,
SizeOfRawData,
PointerToRawData,
PointerToRelocations,
PointerToLinenumbers;
WORD NumberOfRelocations,
NumberOfLinenumbers;
DWORD Characteristics;
}
( the identation is wrong here... )
Btw, my problem is, how to acess the union elements ?
I try this:
//...
scth[0].Misc.VirtualSize = 15;
//...
But, the compiler return that error:
main.d(151): Error: need 'this' for 'VirtualSize' of type 'uint'
On Monday, 14 July 2014 at 13:00:21 UTC, bearophile wrote:
Alexandre:
I get a lot of problens, to convert 'strings' to UCHAR... :/
I suggest you to take a look at the D docs and understand what
D fixed-sized arrays are, dynamic arrays, and strings (that are
dynamic arrays).
Bye,
bearophile
Undo struct slicing by type-punning
Hi,
I am porting C++ code that undo "Object Slicing" by casting
const-references:
http://en.wikipedia.org/wiki/Object_slicing
My translation in D Code
struct A
{
// stuff
}
struct B
{
A a;
alias a this;
// stuff
}
void myFunction(ref const(A) a)
{
if ()
{
// here goes the converstion to a B reference
myFunction2(*cast(const(B)*)(&a)); // using pointer to do
type-punning
}
}
To do this, I need to by guaranteed an object passed through ref
const(A) is never, ever passed by value. Is it safe to assume?
Re: Compile time regex matching
On 07/14/14 13:42, Philippe Sigaud via Digitalmars-d-learn wrote:
> asserts get an entire copy of the parse tree. It's a bit wasteful, but
> using 'immutable' directly does not work here, but this is OK:
>
> enum res = MyRegex("abcabcdefFOOBAR"); // compile-time parsing
> immutable result = res; // to avoid copying the enum value everywhere
static immutable result = MyRegex("abcabcdefFOOBAR"); // compile-time parsing
> The static asserts then works (not the toString, though). Maybe
diff --git a/pegged/peg.d b/pegged/peg.d
index 98959294c40e..307e8a14b1dd 100644
--- a/pegged/peg.d
+++ b/pegged/peg.d
@@ -55,7 +55,7 @@ struct ParseTree
/**
Basic toString for easy pretty-printing.
*/
-string toString(string tabs = "")
+string toString(string tabs = "") const
{
string result = name;
@@ -262,7 +262,7 @@ Position position(string s)
/**
Same as previous overload, but from the begin of P.input to p.end
*/
-Position position(ParseTree p)
+Position position(const ParseTree p)
{
return position(p.input[0..p.end]);
}
[completely untested; just did a git clone and fixed the two
errors the compiler was whining about. Hmm, did pegged get
faster? Last time i tried (years ago) it was unusably slow;
right now, compiling your example, i didn't notice the extra
multi-second delay that was there then.]
artur
Re: SImple C++ code to D
Alexandre: I get a lot of problens, to convert 'strings' to UCHAR... :/ I suggest you to take a look at the D docs and understand what D fixed-sized arrays are, dynamic arrays, and strings (that are dynamic arrays). Bye, bearophile
Re: SImple C++ code to D
Andrea Fontana: Is there any counter-indication with this: immutable ubyte[5] stub = x"b8 01 4c cd 21".representation; ? See: https://issues.dlang.org/show_bug.cgi?id=10454 https://issues.dlang.org/show_bug.cgi?id=5909 Is it a compile time value? Generally you need module-level values or enums to be sure a value is compile-time. In this case it is probably not. Bye, bearophile
Re: SImple C++ code to D
immutable ubyte[5] stub = x"b8 01 4c cd 21".representation;
that is a Real-Mode Stub Program
On Monday, 14 July 2014 at 12:32:38 UTC, Andrea Fontana wrote:
Is there any counter-indication with this:
immutable ubyte[5] stub = x"b8 01 4c cd 21".representation;
?
Is it a compile time value?
On Monday, 14 July 2014 at 12:18:20 UTC, bearophile wrote:
Alexandre:
Look at line 114 of my code: http://dpaste.com/3B5WYGV
The indentations are messed up.
peh.Signature = ('\0' << 8) + ('\0' << 8) + ('E' << 8) + 'P';
You need shifts 8, 16, 24...
alias PIMAGE_DOS_HEADER = IMAGE_DOS_HEADER*;
I don't see much need for such aliases.
auto peh = cast(PIMAGE_NT_HEADERS32)&image[0x80];
I suggest to avoid magic constants like that 0x80, like I have
avoided it here:
memcpy(&image[IMAGE_DOS_HEADER.sizeof],
Bye,
bearophile
Re: DStyle: Braces on same line
On Sunday, 13 July 2014 at 17:24:40 UTC, Timon Gehr wrote: but separate-line opening braces definitely make it easier to see where scopes begin and end. This is the only argument I have heard in favour of doing this, but it is not actually valid. This critique might apply to Lisp style. It is perfectly valid and much more important :P
Re: SImple C++ code to D
I don't see much need for such aliases. Ok, how I can reduce the number of aliaSs ? I suggest to avoid magic constants like that 0x80, like I have avoided it here: memcpy(&image[IMAGE_DOS_HEADER.sizeof], Btw, I need to start that part of code in x80 Look, that is my C++ code base: http://dpaste.com/1MMZK4R I get a lot of problens, to convert 'strings' to UCHAR... :/
Re: SImple C++ code to D
Is there any counter-indication with this:
immutable ubyte[5] stub = x"b8 01 4c cd 21".representation;
?
Is it a compile time value?
On Monday, 14 July 2014 at 12:18:20 UTC, bearophile wrote:
Alexandre:
Look at line 114 of my code: http://dpaste.com/3B5WYGV
The indentations are messed up.
peh.Signature = ('\0' << 8) + ('\0' << 8) + ('E' << 8) + 'P';
You need shifts 8, 16, 24...
alias PIMAGE_DOS_HEADER = IMAGE_DOS_HEADER*;
I don't see much need for such aliases.
auto peh = cast(PIMAGE_NT_HEADERS32)&image[0x80];
I suggest to avoid magic constants like that 0x80, like I have
avoided it here:
memcpy(&image[IMAGE_DOS_HEADER.sizeof],
Bye,
bearophile
Re: DStyle: Braces on same line
On Sunday, 13 July 2014 at 16:10:31 UTC, Gary Willoughby wrote: Here is the 'official' style that is followed by most people including me. http://dlang.org/dstyle.html Unrelated to my original question. I already read that before asking.
Re: SImple C++ code to D
Alexandre:
Look at line 114 of my code: http://dpaste.com/3B5WYGV
The indentations are messed up.
peh.Signature = ('\0' << 8) + ('\0' << 8) + ('E' << 8) + 'P';
You need shifts 8, 16, 24...
alias PIMAGE_DOS_HEADER = IMAGE_DOS_HEADER*;
I don't see much need for such aliases.
auto peh = cast(PIMAGE_NT_HEADERS32)&image[0x80];
I suggest to avoid magic constants like that 0x80, like I have
avoided it here:
memcpy(&image[IMAGE_DOS_HEADER.sizeof],
Bye,
bearophile
Re: new properties for basic types
On Monday, 14 July 2014 at 11:28:15 UTC, Philippe Sigaud via
Digitalmars-d-learn wrote:
Halas, that's not what the OP wants. He needs properties on the
*type*
itself: int.foo instead of foo!int.
Yes, exactly.
So no, this is not possible.
Hmm.
So how do I use stuff like this:
template defaultInit(T)
{
static if (!is(typeof({ T v = void; })))// inout(U)
@property T defaultInit(T v = T.init);
else
@property T defaultInit();
}
(this is from std.traits - ok, it's private, but anyway)
Because I have seen nowhere anything like defaultInit!T (or
T.defaultInit)
and don't understand why here the attribute @property is used.
Why does it make a difference, and how?
Re: SImple C++ code to D
And some other strange thing is, the generate struct in PE file is wrong.. look at imagens... As it should be...: http://i.imgur.com/4z1T3jF.png And how is being generated...: http://i.imgur.com/Oysokuh.png My actual source is that: http://dpaste.com/2TZKWF5 On Monday, 14 July 2014 at 11:55:18 UTC, Alexandre wrote: Look at line 114 of my code: http://dpaste.com/3B5WYGV Have a more better way to make this conversion ? *(DWORD*)"PE\0\0" ?
Re: SImple C++ code to D
Look at line 114 of my code: http://dpaste.com/3B5WYGV Have a more better way to make this conversion ? *(DWORD*)"PE\0\0" ?
Re: Compile time regex matching
> I am trying to write some code that uses and matches to regular expressions
> at compile time, but the compiler won't let me because matchFirst and
> matchAll make use of malloc().
>
> Is there an alternative that I can use that can be run at compile time?
You can try Pegged, a parser generator that works at compile-time
(both the generator and the generated parser).
https://github.com/PhilippeSigaud/Pegged
docs:
https://github.com/PhilippeSigaud/Pegged/wiki/Pegged-Tutorial
It's also on dub:
http://code.dlang.org/packages/pegged
It takes a grammar as input, not a single regular expression, but the
syntax is not too different.
import pegged.grammar;
mixin(grammar(`
MyRegex:
foo <- "abc"* "def"?
`));
void main()
{
enum result = MyRegex("abcabcdefFOOBAR"); // compile-time parsing
// everything can be queried and tested at compile-time, if need be.
static assert(result.matches == ["abc", "abc", "def"]);
static assert(result.begin == 0);
static assert(result.end == 9);
pragma(msg, result.toString()); // parse tree
}
It probably does not implement all those regex nifty features, but it
has all the usual Parsing Expression Grammars powers. It gives you an
entire parse result, though: matches, children, subchildren, etc. As
you can see, matches are accessible at the top level.
One thing to keep in mind, that comes from the language and not this
library: in the previous code, since 'result' is an enum, it'll be
'pasted' in place everytime it's used in code: all those static
asserts get an entire copy of the parse tree. It's a bit wasteful, but
using 'immutable' directly does not work here, but this is OK:
enum res = MyRegex("abcabcdefFOOBAR"); // compile-time parsing
immutable result = res; // to avoid copying the enum value everywhere
The static asserts then works (not the toString, though). Maybe
someone more knowledgeable than me on DMD internals could certify it
indeed avoid re-allocating those parse results.
Re: new properties for basic types
Halas, that's not what the OP wants. He needs properties on the *type* itself: int.foo instead of foo!int. So no, this is not possible.
Re: new properties for basic types
On Monday, 14 July 2014 at 10:28:30 UTC, Dominikus Dittes Scherkl
wrote:
Is it possible to write custom properties for basic types, so
that I can write e.g. "int.myProp" instead of "myProp!int()"
[analogue to x.myProp instead of myProp(x)]?
yes, just define a funciton with the first parameter int:
```d
@property int triple(int x)
{
return x * 3;
}
void main()
{
int x = 4;
assert(12 == x.triple);
}
```
Re: DMDScript
On Sunday, 13 July 2014 at 07:18:38 UTC, Jason King wrote:
On Friday, 11 July 2014 at 15:45:42 UTC, Chris wrote:
Tried to compile on linux, got this error message (I guess I
can fix it):
dmd -c textgen.d
textgen.d(36): Error: cannot implicitly convert expression
("DMDScript fatal runtime error: ") of type string to char[]
.. bunch more errors.
You might try
https://github.com/DmitryOlshansky/DMDScript which, according
to it's notes has changes to make it compatible with D2.
Just tried this. First, I had to replace import std.ctype; with
import core.stdc.ctype. No big deal, but now I get this
make -fposix.mak
dmd -lib -O -release -inline -d dmdscript/darguments.d
dmdscript/darray.d dmdscript/dboolean.d dmdscript/ddate.d
dmdscript/ddeclaredfunction.d dmdscript/derror.d
dmdscript/dfunction.d dmdscript/dglobal.d dmdscript/dmath.d
dmdscript/dnative.d dmdscript/dnumber.d dmdscript/dobject.d
dmdscript/dregexp.d dmdscript/dstring.d dmdscript/errmsgs.d
dmdscript/expression.d dmdscript/functiondefinition.d
dmdscript/identifier.d dmdscript/ir.d dmdscript/irstate.d
dmdscript/iterator.d dmdscript/lexer.d dmdscript/opcodes.d
dmdscript/parse.d dmdscript/program.d dmdscript/property.d
dmdscript/date.d dmdscript/dateparse.d dmdscript/datebase.d
dmdscript/protoerror.d dmdscript/RandAA.d dmdscript/scopex.d
dmdscript/outbuffer.d dmdscript/script.d dmdscript/statement.d
dmdscript/symbol.d dmdscript/text.d dmdscript/regexp.d
dmdscript/threadcontext.d dmdscript/utf.d dmdscript/value.d
dmdscript/extending.d -ofdmdscriptlib.a
dmdscript/dregexp.d(487): Error: function
dmdscript.dregexp.Dregexp.Call multiple overrides of same function
dmdscript/dobject.d(47): Error: cannot take address of
thread-local variable foo at compile time
make: *** [dmdscriptlib.a] Error 1
My idea is to use (at least test) DMDScript for server side JS.
new properties for basic types
Is it possible to write custom properties for basic types, so that I can write e.g. "int.myProp" instead of "myProp!int()" [analogue to x.myProp instead of myProp(x)]?
Re: std.algorithm.among
Ola Fosheim Grøstad: On Sunday, 13 July 2014 at 20:55:25 UTC, bearophile wrote: D doesn't carry the range of mutable variables across different expressions. What is the reasoning behind this kind of special-casing? Compiler simplicity and to avoid flow analysis. The value range is kept across const expressions since 2.066. Bye, bearophile
