ushort arithmetic question
Shouldn't this code work? Looking at the arithmetic conversions section
of http://dlang.org/type.html, point 4.1 makes me think that I shouldn't
be getting the error since they are the same type.
void main()
{
ushort v1 = 1;
ushort v2 = 1;
ushort v3 = v1 + v2;
}
test.d(5): Error: cannot implicitly convert expression (cast(int)v1 + cast
(int)v2) of type int to ushort
Re: ushort arithmetic question
On Fri, 25 Oct 2013 11:51:03 -0700, Ali Çehreli wrote:
On 10/25/2013 11:45 AM, Jonathan Crapuchettes wrote:
Shouldn't this code work? Looking at the arithmetic conversions section
of http://dlang.org/type.html, point 4.1 makes me think that I
shouldn't be getting the error since they are the same type.
void main()
{
ushort v1 = 1; ushort v2 = 1; ushort v3 = v1 + v2;
}
test.d(5): Error: cannot implicitly convert expression (cast(int)v1 +
cast (int)v2) of type int to ushort
But there is 4.0 before 4.1: :)
4. Else the integer promotions are done on each operand, followed by:
1. If both are the same type, no more conversions are done.
Note integer promotions are done on each operand. In other words, e.g.
there is no arithmetic operation on a ushort. The expression v1 + v2 is
performed as two ints.
Ali
Thank you for pointing that out for me. I missed that part.
Jonathan
inout method is not callable using a const object
Can someone help me understand how to correct this error?
Error: inout method ...ValidSparseDataStore.opIndex is not callable using
a const object
The specific method is defined as:
struct ValidSparseDataStore
{
inout(DataT*) opIndex(const Address addr) inout
{
if (auto node = findNode(addr))
return cast(inout)(node.data);
return null;
}
private ValidSparseNode* findNode(const Address ids) const
{
...
}
}
Thank you,
JC
Re: Defining inout returned values for ranges
On Thu, 05 Sep 2013 23:32:10 +0200, anonymous wrote:
On Thursday, 5 September 2013 at 19:19:42 UTC, Jonathan Crapuchettes
wrote:
On Wed, 04 Sep 2013 11:49:41 +0200, anonymous wrote:
[...]
You can use a Template This Parameter [1] instead of inout:
auto opSlice(this This)()
{
static if(is(This == const)) alias QualifiedT = const
T;
else alias QualifiedT = T;
static struct Range {
QualifiedT front() @property {
[1] http://dlang.org/template.html#TemplateThisParameter
Thank you for the help. That worked, but now I ran into another similar
issue. What if the Range struct is being defined outside of the opSlice
method? I have a number of methods in a struct that return the same
range type and would rather not have to have duplicate code or need to
use mixins.
JC
Templatize Range and pass it This:
static struct Range(This)
{
static if(is(This == const)) alias QualifiedT = const T;
else alias QualifiedT = T;
QualifiedT front() @property {...}
}
auto opSlice(this This)()
{
return Range!This();
}
... more methods in the style of opSlice ...
If you need QualifiedT in opSlice, make it a template over This,
too.
Thank you again. It all appears to be working correctly.
JC
Re: inout method is not callable using a const object
On Fri, 06 Sep 2013 13:27:20 -0700, Ali Çehreli wrote:
On 09/06/2013 01:14 PM, Jonathan Crapuchettes wrote:
Can someone help me understand how to correct this error?
Error: inout method ...ValidSparseDataStore.opIndex is not callable
using a const object
That error is about opIndex but we don't see any code that makes that
call.
The specific method is defined as:
struct ValidSparseDataStore {
inout(DataT*) opIndex(const Address addr) inout {
if (auto node = findNode(addr))
return cast(inout)(node.data);
return null;
}
private ValidSparseNode* findNode(const Address ids) const {
...
}
}
Thank you,
JC
I can reproduce it with this code:
struct S {
void foo(int) inout {}
}
void main()
{
const s = S();
s.foo(42); // -- works s.foo(); // -- ERROR
}
Error: inout method deneme.S.foo is not callable using a const object
I can't know whether this matches your case but the compiler should
error about not finding a matching foo() overload instead of bringing
the inout into the discussion.
Ali
Sorry for not including the call site. Here is an example of the call:
void main()
{
auto store = ...;
//add items to the storage
const cStore = store;
auto dp = cStore[16057];//-- ERROR
}
I can try to minimize the code to a working example if needed.
Thank you,
JC
Re: inout method is not callable using a const object
On Fri, 06 Sep 2013 14:08:19 -0700, Ali Çehreli wrote:
I think it is the same issue then.
On 09/06/2013 02:00 PM, Jonathan Crapuchettes wrote:
inout(DataT*) opIndex(const Address addr) inout {
Unless Address is an alias of int, there is no matching opIndex overload
for the following call:
auto dp = cStore[16057];//-- ERROR
Ali
Thank you for your help. For some reason, no one else in the office
noticed that problem. In my code Address was something like TypeTuple!
(int, char) and I was trying to call opIndex(int, int).
Thank you again.
Re: Defining inout returned values for ranges
On Wed, 04 Sep 2013 11:49:41 +0200, anonymous wrote:
On Wednesday, 4 September 2013 at 00:56:39 UTC, Jonathan Crapuchettes
wrote:
If a range struct (Range) is defined inside another struct (Test), how
can the constness or mutability of Test be attributed to the return
type of Range.front? I'm running into this problem because I need the
range to be iterated, but I need the pointer in T to be marked const
when appropriate.
Thank you,
JC
Pseudo-Example:
struct Test {
static struct T {
uint* ptr;
}
...
auto opSlice() inout {
static struct Range {
inout(T) front() @property {
...
}
...
}
return Range();
}
}
You can use a Template This Parameter [1] instead of inout:
auto opSlice(this This)()
{
static if(is(This == const)) alias QualifiedT = const T;
else alias QualifiedT = T;
static struct Range {
QualifiedT front() @property {
[1] http://dlang.org/template.html#TemplateThisParameter
Thank you for the help. That worked, but now I ran into another similar
issue. What if the Range struct is being defined outside of the opSlice
method? I have a number of methods in a struct that return the same range
type and would rather not have to have duplicate code or need to use
mixins.
JC
Defining inout returned values for ranges
If a range struct (Range) is defined inside another struct (Test), how
can the constness or mutability of Test be attributed to the return type
of Range.front? I'm running into this problem because I need the range to
be iterated, but I need the pointer in T to be marked const when
appropriate.
Thank you,
JC
Pseudo-Example:
struct Test
{
static struct T
{
uint* ptr;
}
...
auto opSlice() inout
{
static struct Range
{
inout(T) front() @property
{
...
}
...
}
return Range();
}
}
Re: Templated Function can't deduce function arguments
On Wed, 22 May 2013 23:28:21 -0400, Jonathan M Davis wrote:
On Wednesday, May 22, 2013 21:31:53 Steven Schveighoffer wrote:
On Wed, 22 May 2013 21:16:44 -0400, Jonathan Crapuchettes
jcrapuchet...@gmail.com wrote:
Can anyone tell me why this doesn't compile? Dmd 2.062 says that it
cannot deduce the template function from arguments types.
import std.stdio;
void main()
{
test!(dchar, int)('b', 6, 'a', 54);
}
template test(Types...)
{
void test(T...)(const Types v, const T values...)
Do you need that last elipsis? I thought you didn't, but not sure.
You don't, and I'm surprised that it compiles, since I don't think that
the elipsis is actually legal there. AFAIK, the only time that an
elipsis is legal in the function arguments is with array variadics; e.g.
auto foo(int[] bar...) {...}
- Jonathan M Davis
The last ellipsis was a remnant of testing. Thank you for pointing that
out. Removing it still doesn't help the compiler deduce the argument
types. It appears that the issue has to do with the usage of the Types
TypeTuple. If the
const Types v
is swapped out for
const dchar v1, const int v2
the code compiles just fine. This makes me wonder if dmd is not
interpreting the Types TypeTuple correctly in the inner-function.
Jonathan
Re: Templated Function can't deduce function arguments
Thank you for the help. Bug report at http://d.puremagic.com/issues/ show_bug.cgi?id=10156
Templated Function can't deduce function arguments
Can anyone tell me why this doesn't compile? Dmd 2.062 says that it
cannot deduce the template function from arguments types.
import std.stdio;
void main()
{
test!(dchar, int)('b', 6, 'a', 54);
}
template test(Types...)
{
void test(T...)(const Types v, const T values...)
{
writefln(%s,%s, v);
foreach (s; values)
writefln(%s,%s, s);
}
}
Thank you,
Jonathan
Re: Named Tuple Names
On Tue, 26 Mar 2013 10:13:03 +0100, Jacob Carlborg wrote: On 2013-03-25 23:58, Jonathan Crapuchettes wrote: Is there a way to get the names of the fields in a named tuple? It looks like the names are actually aliases. Perhaps fieldSpecs. Well, that gets you a FieldSpec template which would work except that it is private. I can get around that using the .stringof and then parsing, but I wish there was a cleaner way to do it. If the FieldSpec template was moved into the public section, it would allow for the name member to be accessed.
Named Tuple Names
Is there a way to get the names of the fields in a named tuple? It looks like the names are actually aliases. Thanks, JC
Re: Function constraint vs const parameter?
That worked great! I wish there was a simpler solution, but thank you very much
for your help.
JC
Ali Çehreli wrote:
On 06/06/2012 10:02 AM, Jonathan Crapuchettes wrote:
I'm running into a problem with the following function definition when
passing in a const(string[]).
public T condenseCountyList(T)(const T inputList) if (is(Unqual!T :
string) || is(Unqual!T : string[]))
I'm getting the Error: template common.condenseCountyList does not
match any function template declaration when calling the function as
condenseCountyList(countyList);
, but if I changed the calling code to
condenseCountyList(cast(string[])countyList)
dmd is happy.
How do I need to change the function constraint to make this work?
Thank you,
Jonathan Crapuchttes
Sorry for being terse but this works:
import std.traits;
import std.array;
template isSomeStringArray(T)
{
enum isSomeStringArray = is (typeof(
{
T variable;
static assert (isSomeString!(typeof(variable.front)));
}()));
}
T condenseCountyList(T)(const T inputList)
if (isSomeString!T || isSomeStringArray!T)
{
return T.init;
}
void main()
{
auto countyList = [ Santa Clara ];
condenseCountyList(countyList);
}
isSomeString is defined in std.traits. isSomeStringArray above uses a number of
D features:
* anonymous delegate
* executing that delegate by () (which is actually never executed)
* typeof, which produces invalid type if the expression illegal
* is, which produces true if the type that it receives is not invalid
* eponymous templates
Ali
Function constraint vs const parameter?
I'm running into a problem with the following function definition when passing in a const(string[]). public T condenseCountyList(T)(const T inputList) if (is(Unqual!T : string) || is(Unqual!T : string[])) I'm getting the Error: template common.condenseCountyList does not match any function template declaration when calling the function as condenseCountyList(countyList); , but if I changed the calling code to condenseCountyList(cast(string[])countyList) dmd is happy. How do I need to change the function constraint to make this work? Thank you, Jonathan Crapuchttes
Re: Global runtime strings help
Thank you for the thought, but the problem here is that the file containing the
strings is only known at runtime from a command line argument. I also have some
global strings that need to be set from the database.
Thank you again,
JC
Jonathan M Davis wrote:
On Friday, September 23, 2011 13:29:08 Jonathan Crapuchettes wrote:
I'm working on an application that requires a large number of strings that
only need to be loaded once at runtime and need to be accessible to all
threads throughout the execution of the program. Some of these strings are
variables like database host and username that need to be read from a file.
Can anyone help me with an example how they might do this task?
Thank you,
JC
immutable string1;
immutable string2;
immtuable string3;
static shared this()
{
string1 = the string;
string2 = the other string;
string3 = funcThatGrabsStringFromFile();
}
immutable variables are implicitly shared. The shared module constructor will
then initialize them before main runs, and all threads will have access to
them.
- Jonathan M Davis
Global runtime strings help
I'm working on an application that requires a large number of strings that only need to be loaded once at runtime and need to be accessible to all threads throughout the execution of the program. Some of these strings are variables like database host and username that need to be read from a file. Can anyone help me with an example how they might do this task? Thank you, JC
Re: Synchronized Linked List Traversal
Thank you for the help. Since I am using D1, I think I will use the pthread mutexes through the C API. Steven Schveighoffer wrote: On Thu, 21 Jan 2010 08:35:50 -0500, Steven Schveighoffer schvei...@yahoo.com wrote: To do this, you need a manual mutex, look in tango.core.sync.Mutex I think. or core.sync.mutex for D2... -Steve
Re: Synchronized Linked List Traversal
Yeah, but I have a lot of code in this project that uses phobos and it would be a major pain (not to mention the time) to switch over. Thank you for the thought, Jonathan Steven Schveighoffer wrote: On Thu, 21 Jan 2010 13:29:37 -0500, Jonathan Crapuchettes jcrapuchet...@gmail.com wrote: Thank you for the help. Since I am using D1, I think I will use the pthread mutexes through the C API. Tango provides mutex objects for D1. -Steve
Synchronized Linked List Traversal
I'm working on a project that requires multi-threading and I am trying to grasp
the best way to work with setting up a linked-list where multiple threads might
try to be setting the next element in the list at the same time.
What I really need to know is if this will work:
Node!(T) child = parent.firstChild;
synchronized (child)
{
while (child.sibling !is null)
child = child.sibling;
child.sibling = node;
}
What I am worried about is that the mutex will not follow the traversal. Any
help would be great.
Thanks you,
Jonathan
UNIX IPC Sockets
I am looking into doing some IPC between two processes using phobos, but ran into a problem when trying to bind a Socket to a unix location. There is an InternetAddress class, but there doesn't appear to be an Address class for the UNIX address family. Can anyone give me an example of how to setup a Socket with an address family type AddressFamily.UNIX? Thank you, JC
