Shouldn't (stream == null) be (stream is null)?
-Eric
From: "adamgoldberg via Digitalmars-d-learn"
To: digitalmars-d-learn@puremagic.com
Sent: Monday, July 22, 2019 3:05:17 PM
Subject: Why does a switch break cause a segmentation fault
Hey, I just happened to be writing a program in D
On Tuesday, 14 August 2018 at 03:01:11 UTC, Cecil Ward wrote:
On Tuesday, 14 August 2018 at 02:53:01 UTC, Cecil Ward wrote:
On Sunday, 12 August 2018 at 12:27:59 UTC, Alex wrote:
On Saturday, 11 August 2018 at 05:17:51 UTC, Cecil Ward wrote:
T myfunc(T)( T x, uint mask )
if ( mask == 3 )
I thought it would work the same way as an interface (which must
be implemented by the direct sub class, otherwise compile error).
But apparently it's possible to implement an abstract function
anywhere in the class hierarchy. That makes it, in this case,
impossible to check during compile
Code below compiles while I would not expect it to compile.
Is there a reason that this compiles?
Specs are a bit lite on abstract classes.
Only thing I found that would need to allow this is: "19.4
functions without bodies"
https://dlang.org/spec/function.html#function-declarations
But
Not a question.
I came up with a nice and simple way to apply operations on an
arbitrary number of members of unknown type of a set of objects
of unknown type. This without having to reimplement these
operations for each class that needs to support the operation(s).
All this without
On Wednesday, 18 July 2018 at 12:10:18 UTC, baz wrote:
Specs are clear : it's a global so it's evaluated at compile
time
(https://dlang.org/spec/declaration.html#global_static_init)
Example code should not compile.
Indeed. Inside a function it does actually work.
And ofcourse for
class
On Monday, 16 July 2018 at 22:16:10 UTC, Adam D. Ruppe wrote:
On Monday, 16 July 2018 at 22:08:34 UTC, Eric wrote:
This makes the compiler crash. Is it illegal code?
Yes, a struct can be moved at any time by the compiler which
means pointers to it can be invalidated at random.
Unless you
Pasted slightly wrong code, last line should be:
List ls = 2;
Question still stands.
This makes the compiler crash. Is it illegal code?
struct List {
private List* head;
private List* tail;
this(int x) {
head = null;
tail = // <-- crasher
}
}
List2 ls = 2;
I am just a bit confused why I had to use tuple() while the doc
Because of the enum, that code was full of errors :/
Got it now:
auto groupIndex(Ts...)() {
import std.meta;
import std.algorithm.comparison : cmp, strcmp = cmp;
enum Comp(N1, N2) = strcmp(N1.stringof,
Ok, solved. It appears you can sort tuples.
I am just a bit confused why I had to use tuple() while the doc
for staticSort states it works on AliasSeq.
auto groupIndex(Ts...)() {
import std.meta;
enum Comp(alias N1, alias N2) = { __traits(identifier,
typeof(N1)) <
Forgot to mention that I also want groupIndex!(A,B) ==
groupIndex!(B,A)
Which I wanted to do by sorting the names.
If that requirement wasn't there it would be as simple as:
auto groupIndex(Ts...)() {
return GroupId!Ts.id;
}
size_t s_nextIdx=1;
struct GroupId(Ts ...) {
static size_t
I am trying to build a string->int dictionary at compile time.
The ints are unique and must not be greater than the number of
unique strings.
So, they are sequential for each string that is not yet indexed.
Example:
size_t idx1 = nameToIndex!"blah"; // 0
size_t idx2 = nameToIndex!"blah2"; //
import std.stdio;
enum A : int { a, b };
enum B : int { a, b };
enum AS : string[2] { a = ["1","2"], b = ["3","4"] };
enum BS : string[2] { a = ["5","6"], b = ["7","8"] };
void func(A a) { writeln("A"); }
void func(B b) { writeln("B"); }
void funcs(AS a) { writeln("AS"); }
void funcs(BS
On Sunday, 2 April 2017 at 04:14:56 UTC, rikki cattermole wrote:
On 02/04/2017 2:37 AM, Eric wrote:
I'm planning on some day putting a package in the DUB
registry. My package
is dependent on my "util" package which is a collection of
stuff I use
across
all my projects. Does this mean I
I'm planning on some day putting a package in the DUB registry.
My package
is dependent on my "util" package which is a collection of stuff
I use across
all my projects. Does this mean I also have to put my util
package in the DUB registry?
Could I just make "util" a git sub module of the
On Saturday, 11 March 2017 at 17:54:55 UTC, ag0aep6g wrote:
On 03/11/2017 06:41 PM, Eric wrote:
I'm trying to build the master branch of DMD on redhat 7.
I get the following errors:
ddmd/root/newdelete.c:26:8: error: expected identifier or ‘(’
before
string constant
extern "C"
^
On Saturday, 11 March 2017 at 17:54:55 UTC, ag0aep6g wrote:
Looks like a C compiler is used instead of a C++ compiler.
Despite the extension, dmd's *.c files are C++ code.
Yes, that's what I thought - redhat has gcc, but not g++. There
must
be a needed compile option...
I'm trying to build the master branch of DMD on redhat 7.
I get the following errors:
ddmd/root/newdelete.c:26:8: error: expected identifier or ‘(’
before string constant
extern "C"
^
ddmd/root/newdelete.c:31:17: error: expected ‘=’, ‘,’, ‘;’, ‘asm’
or ‘__attribute__’ before ‘new’
Yes, it's a bug. Please file an issue.
Meanwhile try this workaround:
class A(T)
{
static assert(is(T : A!T), "...");
}
Bug report filed, and thanks for the workaround.
-Eric
is(T : A!T) tells if T can automatically be converted to A!T. The
last line below is doing just that, yet the template constraint
does not work.
class A(T) if (is(T : A!T))
{
}
// if (is(T : A!T)) gives this error:
// Error: template instance x.A!(B) does not match
//template
On Friday, 15 April 2016 at 18:28:58 UTC, Eric wrote:
line 6 can be fixed like this: "const I!(J) i = a;"
Now if I can just figure out how to fix line 15...
This works:
1 alias J = const C;
2
3 void main(string[] args)
4 {
5 J a = new C();
6 const (I!(J)) i = a;
7 }
8
On Friday, 15 April 2016 at 18:22:02 UTC, Eric wrote:
On Friday, 15 April 2016 at 17:43:59 UTC, ag0aep6g wrote:
On 15.04.2016 19:13, Eric wrote:
1 alias J = const C;
2
3 void main(string[] args)
4 {
5 J a = new C();
6 I!(J) i = a;
7 }
8
9 interface I(V) { }
On Friday, 15 April 2016 at 17:43:59 UTC, ag0aep6g wrote:
On 15.04.2016 19:13, Eric wrote:
1 alias J = const C;
2
3 void main(string[] args)
4 {
5 J a = new C();
6 I!(J) i = a;
7 }
8
9 interface I(V) { }
10
11 class F(V) if (is(V : I!(V))) { }
12
13
1 alias J = const C;
2
3 void main(string[] args)
4 {
5 J a = new C();
6 I!(J) i = a;
7 }
8
9 interface I(V) { }
10
11 class F(V) if (is(V : I!(V))) { }
12
13 class C : I!(J)
14 {
15 F!(J) m;
16 }
The above code gives the following compile error:
Error:
On Monday, 11 April 2016 at 00:55:44 UTC, Mike Parker wrote:
On Sunday, 10 April 2016 at 17:19:14 UTC, Eric wrote:
I am getting this error when I compile:
Error: Internal Compiler Error: unsupported type const(string)
No line number is given. Does anyone know what causes this?
compiler
I am getting this error when I compile:
Error: Internal Compiler Error: unsupported type const(string)
No line number is given. Does anyone know what causes this?
compiler version = v2.071.0
-Eric
BTW, why do you need FreeImage to create image? Isn't it just
possible inside dlangui?
This is basically my question. Is there a drawing engine that
can draw lines, circles, and shapes as well as single pixels?
-Eric
@safe
class Y { }
@safe
class X { }
@safe
class Z
{
int x;
this()
{
if (typeid(X) == typeid(Y)) x = 1; // Compile Error
else x = 2;
}
}
void main() { new Z; }
// test.d(19): Error: safe function 'test.Z.this'
// cannot call system function 'object.opEquals'
On Tuesday, 25 November 2014 at 02:48:43 UTC, Jonathan M Davis
via Digitalmars-d-learn wrote:
On Monday, November 24, 2014 22:12:08 Eric via
Digitalmars-d-learn wrote:
@safe
class Y { }
@safe
class X { }
@safe
class Z
{
int x;
this()
{
if (typeid(X) == typeid(Y)) x
On Saturday, 22 November 2014 at 09:57:55 UTC, anonymous wrote:
On Saturday, 22 November 2014 at 02:37:21 UTC, Eric wrote:
I know I can make a class immutable, but the problem is I want
to constrain a template parameter to only immutable types,
and I want to use class types.
template Foo(T :
On Saturday, 22 November 2014 at 15:20:55 UTC, drug wrote:
I tried to pass pointer to static array but it didn't work.
try this:
import std.stdio;
void change(ref int[3] arr)
{
arr[1] = 6;
}
void main()
{
int[3] a = [1, 2, 3];
writeln(a = , a);
change(a);
writeln(a = ,
On Saturday, 22 November 2014 at 15:20:55 UTC, drug wrote:
I tried to pass pointer to static array but it didn't work.
Also, if you really want to be lame and actually use a pointer
try this:
import std.stdio;
void change(int *arr)
{
arr[1] = 6;
}
void main()
{
int[3] a = [1, 2, 3];
On Saturday, 22 November 2014 at 15:57:40 UTC, ketmar via
Digitalmars-d-learn wrote:
On Sat, 22 Nov 2014 15:45:51 +
Eric via Digitalmars-d-learn
digitalmars-d-learn@puremagic.com wrote:
Maybe this is not so lame because change() can take
any length of static array.
void change (int
On Saturday, 22 November 2014 at 16:07:25 UTC, drug wrote:
On 22.11.2014 19:34, ketmar via Digitalmars-d-learn wrote:
On Sat, 22 Nov 2014 18:20:44 +0400
drug via
Digitalmars-d-learndigitalmars-d-learn@puremagic.com wrote:
I tried to pass pointer to static array but it didn't work.
i tried
On Saturday, 22 November 2014 at 17:06:29 UTC, anonymous wrote:
On Saturday, 22 November 2014 at 15:00:00 UTC, Eric wrote:
Yes, but if I don't declare the class T as immutable, I don't
think this constraint will work.
You're mistaken. It works just fine.
class X /* not immutable */
{
But I'm not sure if maybe I changed to much about it.
My point is, that I think it's generally a good idea to be
flexible when possible, and not make (im)mutability demands
unless actually necessary.
You may know the following, but I feel like there may be some
confusion about it: Note that
Suppose I have:
module test;
class X { }
class Y : X { }
Y y = new Y;
X x = y;
assert(is(typeof(x) == test.Y); // this assertion will fail
assert(typeid(x).toString() == test.Y); // this assertion will
pass
Is there a way I can check the type of x without doing
a string comparison?
-Eric
On Friday, 21 November 2014 at 22:25:32 UTC, anonymous wrote:
On Friday, 21 November 2014 at 22:15:37 UTC, Eric wrote:
Suppose I have:
module test;
class X { }
class Y : X { }
Y y = new Y;
X x = y;
assert(is(typeof(x) == test.Y); // this assertion will fail
assert(typeid(x).toString() ==
On Friday, 21 November 2014 at 22:52:54 UTC, H. S. Teoh via
Digitalmars-d-learn wrote:
On Fri, Nov 21, 2014 at 10:30:51PM +, Eric via
Digitalmars-d-learn wrote:
On Friday, 21 November 2014 at 22:25:32 UTC, anonymous wrote:
On Friday, 21 November 2014 at 22:15:37 UTC, Eric wrote
immutable class X
{
private int x;
this(int x) { this.x = x; }
...
override size_t toHash(); // error: can't override mutable
method
}
Since toHash() cannot be overridden in an immutable class,
is there a work-around?
In other words,
immutable X x1 = new immutable X(5);
But think about if enforced immutability is really what you
want.
You don't need to mark the fields immutable to be able to
construct immutable Xs. A `pure` constructor is handy, as it can
construct both mutable and immutable objects.
class X
{
private int x;
this(int x) pure {
Hi -
I've never designed a recursive template before, but I think
that would solve my problem. What I would like is
someting like this:
class X(V, K...)
{
// I want to declare a type based on K and V such
// that for X!(V, int, string, double) the resulting
// declaration would be:
Thanks!
-Eric
On Saturday, 15 November 2014 at 18:49:32 UTC, anonymous wrote:
On Saturday, 15 November 2014 at 18:30:00 UTC, Eric wrote:
Hi -
I've never designed a recursive template before, but I think
that would solve my problem. What I would like is
someting like this:
class X(V,
Suppose I have some memory allocated on the heap, and I have
two pointers pointing to the beginning and end of a contiguous
segment
of that memory. Is there a way I can convert those two pointers
to an array slice without actually copying anything within the
segment?
Thx,
Eric
On Thursday, 31 July 2014 at 19:43:00 UTC, bearophile wrote:
Eric:
Suppose I have some memory allocated on the heap, and I have
two pointers pointing to the beginning and end of a contiguous
segment
of that memory. Is there a way I can convert those two
pointers
to an array slice without
On Thursday, 31 July 2014 at 20:59:46 UTC, Vlad Levenfeld wrote:
On Thursday, 31 July 2014 at 20:43:11 UTC, bearophile wrote:
Take a look at the asm!
Bye,
bearophile
I use DMD and Dub, how do I view the asm?
Actually I did't think to look at the asm, mainly because
I've never bothered to
I have been writing several lexers and parsers. The grammars I
need to
parse are really complex, and consequently I didn't feel
confident about
the code quality, especially in the lexers. So I decided to jump
on the functional progamming bandwagon to see if that would help.
It definitely
By the way, do you really mean to stop on '0' and '9'? Do you
perhaps mean a '0' || a '9'?
Yes, my bad...
On Tuesday, 22 July 2014 at 17:09:29 UTC, bearophile wrote:
Eric:
while (!buf.empty())
{
p++;
buf.popFront();
Those () can be omitted, if you mind the noise (but you can
also keep them).
if (buf.front() = '0' || buf.front() = '9') break;
std.ascii.isDigit
There are a lot of discussions in the forums about how @property
should or could be implemented. But I can't seem to find anything
that explains why or when I should use @property with the current
compiler. Can anyone explain why and when I should use the
@property tag?
Thx.
Eric
Use @property when you want a pseudo-variable or something that
might be conceptually considered a property of the object,
i.e. to do this:
auto blah = thing.someProperty;
thing.someProperty = blahblah;
This is basically what I suspected. But why
write:
@property int getValue() {
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