Re: Manipulate slice or specific element of range and return range
On Wednesday, 21 March 2018 at 11:30:28 UTC, Timoses wrote:
Hey,
I'm struggling to find a way to achieve this. I've looked
through std.algorithm but didn't find anything.. Maybe I'm
blind.
What I would like to do is filter out all spaces in a string
and change the front letter to lower case:
string m = "My Capital String";
string lower = m
.filter!(c => c != ' ')
.!(0, c => c.toLower) // executeAt does not
exist
.array.to!string;
assert(lower == "myCapitalString");
or sth like
m.filter!(...)
.map!((element, int index) {
if (index == 0)
return element.toLower;
else
break; // stop since we are done manipulating
range
});
Anyway to do this?
No need for regular expressions. D is powerful enough without
them:
```
alias lowercased = (m, n) =>
m.take(n).asLowerCase.chain(m.drop(n));
```
https://run.dlang.io/is/cSL0si
Re: Understanding slide
On Thursday, 22 March 2018 at 03:58:35 UTC, Seb wrote: On Thursday, 22 March 2018 at 03:39:38 UTC, Jordan Wilson wrote: auto a = iota(5).slide!(Yes.withPartial)(3); auto b = iota(5).slide!(No.withPartial)(3); assert (a.equal(b)); The assert passes, but I would expect it to fail? They both are: [[0,1,2],[1,2,3],[2,3,4]] Thanks, Jordan See: https://forum.dlang.org/post/asocdlqaihkskiilr...@forum.dlang.org PR to improve the docs: https://github.com/dlang/phobos/pull/6322
Re: Understanding slide
On Thursday, 22 March 2018 at 03:39:38 UTC, Jordan Wilson wrote: auto a = iota(5).slide!(Yes.withPartial)(3); auto b = iota(5).slide!(No.withPartial)(3); assert (a.equal(b)); The assert passes, but I would expect it to fail? They both are: [[0,1,2],[1,2,3],[2,3,4]] Thanks, Jordan See: https://forum.dlang.org/post/asocdlqaihkskiilr...@forum.dlang.org
Understanding slide
auto a = iota(5).slide!(Yes.withPartial)(3); auto b = iota(5).slide!(No.withPartial)(3); assert (a.equal(b)); The assert passes, but I would expect it to fail? They both are: [[0,1,2],[1,2,3],[2,3,4]] Thanks, Jordan
Re: recursive template expansion: Why does this not compile?
On Wednesday, March 21, 2018 22:50:32 Ontonator via Digitalmars-d-learn wrote: > On Wednesday, 21 March 2018 at 06:39:22 UTC, ag0aep6g wrote: > > On 03/21/2018 01:47 AM, Ontonator wrote: > >> The following code does not compile: > >>> [...] > >> > >> It gives the error: > >>> [...] > >> > >> The aliases do not have to be aliases, as long as there is > >> some reference to the class (e.g. method and variable > >> declarations also work). What exactly is the reason for this > >> error? > > > > Compiler bug. It works when you move the declaration of `B` > > before the one of `A`. Order shouldn't matter there. > > Is this a known bug, or should I report it? If you can't find it searching on bugzilla, report it. - Jonathan M Davis
Re: D's type declarations seem to read right to left.
On Wednesday, March 21, 2018 20:07:09 tipdbmp via Digitalmars-d-learn wrote: > D's type declarations seem to read right to left. > > > int an_integer; > > int[10] an_array_of_10_integers; > int[10]* a_pointer_to_an_array_of_10_integers = > _array_of_10_integers; > > int*[10] an_array_of_10_pointers_to_integers; > int*[10]* a_pointer_to_an_array_of_10_pointers_to_integers = > _array_of_10_pointers_to_integers; > > int[3][2] an_array_of_2_arrays_of_3_integers; > int[string] a_hashtable_with_string_keys_and_integer_values; > > int[3][string][2] > an_array_of_2_hashtables_with_string_keys_and_array_of_3_integers_values; > > int function(float) > a_pointer_to_a_function_that_takes_a_float_and_returns_an_integer; > int function(float)[10] > an_array_of_10_functions_that_take_floats_and_return_integers; > > > I think this is a big improvement over C's "spiral" way of > reading types: http://www.unixwiz.net/techtips/reading-cdecl.html > I guess it could've been left to right, but... it's okay. In principle, D types read in more or less the same way as C types. The main differences are that we simplifed how function pointers are declared (making them more like function prototypes) and got rid of the types on the right-hand side of the name. e.g. int[10] arr; instead of int arr[10]; Both read outward from the type, but the D way is then right-to-left in this case, whereas the C way is left-to-right even though they're both reading outward from the type. So, this makes it look like D reads right-to-left, but it'st still reading outward from the type. e.g. if you look at how dynamic arrays are declared, it's still outward from the type, not right-to-left. e.g. auto foo = new int[][](10, 14); assert(foo.length == 10); assert(foo[0].length == 14); vs int[10][14] foo; assert(foo.length == 14); assert(foo[0].length == 10); The fact that parens are used for const does muck with things a bit though. In C/C++, you have const int* p; which is equivalent to int const* p; but for whatever reason, both are allowed. The second one reads outward from the type, whereas the first one essentially breaks those rules a bit. And D essentially went with the first one, because the equivalent would be const(int)* p; and there's no way to put the const on the right. So, while the pointer portion of the type does read outward from the type, const doesn't really. So, overall, D cleaned things up, but it didn't actually make them fully consistent either. - Jonathan M Davis
Re: recursive template expansion: Why does this not compile?
On Wednesday, 21 March 2018 at 06:39:22 UTC, ag0aep6g wrote: On 03/21/2018 01:47 AM, Ontonator wrote: The following code does not compile: [...] It gives the error: [...] The aliases do not have to be aliases, as long as there is some reference to the class (e.g. method and variable declarations also work). What exactly is the reason for this error? Compiler bug. It works when you move the declaration of `B` before the one of `A`. Order shouldn't matter there. Is this a known bug, or should I report it?
Re: Slow start up time of runtime (correction: Windows real-time protection)
On Wednesday, 21 March 2018 at 13:26:48 UTC, HeiHon wrote: In Windows Security Center Settings (where you can disable realtime scan) there is also an entry "Exclusions" (in german windows "Ausschlüsse"). I added exclusions for the folder, where I installed dmd and ldc and I added an exclusion for the folder, where I compile my D programs. Now startup of dmd and freshly compiled programs is fast again. Awesome tip!
Re: Need example of usage DerelictPQ
On Wednesday, 24 December 2014 at 11:56:40 UTC, Suliman wrote:
Could anybody provide any simple examples of usage DerelictPQ.
I do not have experience of C, and I can't understand how to
use this driver.
I need just basics like connect, select and insert.
http://code.dlang.org/packages/derelict-pq
thanks!
A bit late, but maybe useful for others, and googling 'dlang
derelict postgres example' brings you here..
The default ubuntu (16.04) postgres version caused runtime errors
for me (DerelictPQ.load()), what worked was installation from
here:
https://www.postgresql.org/download/linux/ubuntu/
the example expects a postgres user/role 'sammy' with password
'sammypw' and a database 'sammy' with a table as shown in
comments and set up as here:
https://www.digitalocean.com/community/tutorials/how-to-install-and-use-postgresql-on-ubuntu-16-04
if you don't specify a host at PQconnectdb() then you might get
an error
'Peer authentication failed for user "sammy"'
when you run the binary as a OS user different from 'sammy', or
you would have to run the program as the postgres user like
sudo -iu sammy /path/to/prog
dub.json
{
"name": "prog",
"targetType": "executable",
"sourceFiles": [ "prog.d" ],
"dependencies": {
"derelict-pq": "~>2.2.0"
}
}
prog.d
import core.stdc.stdlib;
import std.stdio;
import std.conv;
import derelict.pq.pq;
/*
CREATE TABLE playground (
equip_id serial PRIMARY KEY,
type varchar (50) NOT NULL,
color varchar (25) NOT NULL,
location varchar(25) check (location in ('north', 'south',
'west', 'east', 'northeast', 'southeast', 'southwest',
'northwest')),
install_date date
);
INSERT INTO playground (type, color, location, install_date)
VALUES ('slide', 'blue', 'south', '2014-04-28');
INSERT INTO playground (type, color, location, install_date)
VALUES ('swing', 'yellow', 'northwest', '2010-08-16');
*/
int main(string[] args)
{
int retval = EXIT_SUCCESS;
DerelictPQ.load();
PGconn* conn = PQconnectdb("user = 'sammy' password = 'sammypw'
dbname = 'sammy' host = '127.0.0.1'");
if (PQstatus(conn) != CONNECTION_OK)
{
writefln("ERROR (connection): %s",
to!string(PQerrorMessage(conn)));
retval = EXIT_FAILURE;
}
else
{
writeln("OK (connection)");
PGresult* result = PQexec(conn, "select * from playground");
if (PQresultStatus(result) != PGRES_TUPLES_OK)
{
writefln("ERROR (result): %s",
to!string(PQerrorMessage(conn)));
retval = EXIT_FAILURE;
}
else
{
writeln("OK (result)");
int nbFields = PQnfields(result);
writeln("nbFields: ", nbFields);
int nbRows = PQntuples(result);
writeln("nbRows: ", nbRows);
for (int f; f < nbFields; f++)
{
writef("%16s", to!string(PQfname(result, f)));
}
writeln("");
for (int r; r < nbRows; r++)
{
for (int f; f < nbFields; f++)
{
ubyte* ub =
cast(ubyte*)(PQgetvalue(result, r, f));
int len = PQgetlength(result, r, f);
char[] c = cast(char[])ub[0..len];
string s = to!string(c);
writef("%16s", s);
}
writeln("");
}
}
PQclear(result);
}
PQfinish(conn);
return retval;
}
If someone has a better way to convert the PQgetvalue() to
string, i'm interested :)
The functions are as follows:
alias da_PQgetvalue = const(ubyte)*
function(const(PGresult)*,int,int);
alias da_PQgetlength = int function(const(PGresult)*,int,int);
have a nice day
Re: Slow start up time of runtime (correction: Windows real-time protection)
On Wednesday, 21 March 2018 at 13:26:48 UTC, HeiHon wrote: I added exclusions for the folder, where I installed dmd and ldc and I added an exclusion for the folder, where I compile my D programs. Now startup of dmd and freshly compiled programs is fast again. I've done this too now, thanks for the tip!
Re: OK, I'm stumped on this one: dstep, struct, mixin, bitfields
On 2018-03-21 20:30, Russel Winder wrote: Thanks to Adam and Ali, it was clear and obvious. Please report and issue so it's not forgotten. -- /Jacob Carlborg
Re: Packages and module import
On 2018-03-21 17:06, Russel Winder wrote: No I wasn't. And it works a treat. Cool :). I recommend having a look at the changelog and the usage information (--help). -- /Jacob Carlborg
Re: D's type declarations seem to read right to left.
On Wednesday, 21 March 2018 at 20:07:09 UTC, tipdbmp wrote: D's type declarations seem to read right to left. int an_integer; int[10] an_array_of_10_integers; int[10]* a_pointer_to_an_array_of_10_integers = _array_of_10_integers; int*[10] an_array_of_10_pointers_to_integers; int*[10]* a_pointer_to_an_array_of_10_pointers_to_integers = _array_of_10_pointers_to_integers; int[3][2] an_array_of_2_arrays_of_3_integers; int[string] a_hashtable_with_string_keys_and_integer_values; int[3][string][2] an_array_of_2_hashtables_with_string_keys_and_array_of_3_integers_values; int function(float) a_pointer_to_a_function_that_takes_a_float_and_returns_an_integer; int function(float)[10] an_array_of_10_functions_that_take_floats_and_return_integers; I think this is a big improvement over C's "spiral" way of reading types: http://www.unixwiz.net/techtips/reading-cdecl.html I guess it could've been left to right, but... it's okay. The way I see it, English "of" flips its operands backwards compared to English's [adjective][noun] syntax: int an_integer; int* an_integer_pointer; int[] an_integer_array; int[3]* an_integer_array(length 3)_pointer; But granted, in English, "of" is more scalable than [adjective][noun].
Re: D's type declarations seem to read right to left.
On Wednesday, 21 March 2018 at 20:07:09 UTC, tipdbmp wrote: I think this is a big improvement over C's "spiral" way of reading types: Yes, D is perfect and has achieved sanity where before there was none. You can read basically anything with little knowledge. void function()[] array_of_funtions; int[]*[]*[string] assoctiavive array of pointers to arrays of pointers to arrays of ints.
D's type declarations seem to read right to left.
D's type declarations seem to read right to left. int an_integer; int[10] an_array_of_10_integers; int[10]* a_pointer_to_an_array_of_10_integers = _array_of_10_integers; int*[10] an_array_of_10_pointers_to_integers; int*[10]* a_pointer_to_an_array_of_10_pointers_to_integers = _array_of_10_pointers_to_integers; int[3][2] an_array_of_2_arrays_of_3_integers; int[string] a_hashtable_with_string_keys_and_integer_values; int[3][string][2] an_array_of_2_hashtables_with_string_keys_and_array_of_3_integers_values; int function(float) a_pointer_to_a_function_that_takes_a_float_and_returns_an_integer; int function(float)[10] an_array_of_10_functions_that_take_floats_and_return_integers; I think this is a big improvement over C's "spiral" way of reading types: http://www.unixwiz.net/techtips/reading-cdecl.html I guess it could've been left to right, but... it's okay.
Re: OK, I'm stumped on this one: dstep, struct, mixin, bitfields
On Wed, Mar 21, 2018 at 07:30:28PM +, Russel Winder via Digitalmars-d-learn
wrote:
[...]
> But :-(
>
> Why does version have to be a keyword?
[...]
version(all) { ... }
version(none) { ... }
version(Posix) { ... }
version(Windows) { ... }
But yeah, using "version" for this purpose makes the very common
identifier "version" unavailable for use. I've been bitten by this
multiple times.
auto version = getVersion();// NG
auto ver = getVersion();// OK
struct PacketHeader {
ushort version; // NG
ushort ver; // OK
}
:-(
T
--
Маленькие детки - маленькие бедки.
Re: OK, I'm stumped on this one: dstep, struct, mixin, bitfields
On Wed, 2018-03-21 at 18:11 +, Adam D. Ruppe via Digitalmars-d- learn wrote: > On Wednesday, 21 March 2018 at 18:00:38 UTC, Russel Winder wrote: > > ubyte, "version", 5, > > > version is a D keyword, so I would suggest trying "version_" > there instead and see if it works. (I'm guessing btw, the error > message was way to long and illegible, but this is an easy first > guess anyway) On Wed, 2018-03-21 at 11:14 -0700, Ali Çehreli via Digitalmars-d-learn wrote: […] > > I think it's because 'version' is a D keyword. :) > > Ali > Thanks to Adam and Ali, it was clear and obvious. But :-( Why does version have to be a keyword? -- Russel. === Dr Russel Winder t: +44 20 7585 2200 41 Buckmaster Roadm: +44 7770 465 077 London SW11 1EN, UK w: www.russel.org.uk signature.asc Description: This is a digitally signed message part
Re: strip() and formattedRead()
On Wednesday, 21 March 2018 at 18:50:18 UTC, Adam D. Ruppe wrote: On Wednesday, 21 March 2018 at 18:44:12 UTC, realhet wrote: Compiling this I get an error: "formattedRead: cannot deduce arguments from (string, string, float, float, float)" What compiler version are you using? The newest versions allow this code, though the old ones require an intermediate variable to satisfy the `ref` requirement on formattedRead (it will want to update that variable to advance it past the characters it read). so either update your version, or just give an and use an intermediate: string s = "".strip; formattedRead(s, ) Thank both of You! You guys are super helpful. (I'm learning from Ali's book and after these instant answers I was like: "I'm not worthy" :D) So I had v2077.1 previously, now I've installed 2079.0 and it all works great.
Re: why does this compile fine, but dies when you run it.
On Wednesday, 21 March 2018 at 18:53:39 UTC, steven kladitis wrote: int[] array3; array3[0]=4; array3 is empty. You are trying to set a value that doesn't exist..
Calling Windows Command
Hi All,
Request your help in calling the windows command to delete all
file and folders recursively as the D function rmdirRecurse does
not delete file in the permission of the file is readonly in
windows 2008 R2
import std.process: execute;
import std.array: empty;
auto RemoveDir () (
auto dFiles = "C:\\Temp\Test1";
auto Step = "run";
if (Step == "run" && !dFiles.empty) {
version(Windows)
{
foreach(d; dFiles) {
execute(["rmdir.exe","-command", "/S /Q", `~d~`]); } } }
return dFiles;
)
void main () {
writeln(RemoveDir);
}
From,
Vino.N
why does this compile fine, but dies when you run it.
import std.stdio;
void main(){
int[3] array1 = [ 10, 20, 30 ];
auto array2 = array1; // array2's elements are different
// from array1's
array2[0] = 11;
int[] array3;
//array4[0]=3;
array3[0]=4;
auto array4 = array3;
writeln(array1,'\n',array2,'\n',array3,'\n',array4);
}
-- windows 7 64 bit ( os ) dmd 2.079.0
-- thanks
-- Steven
Re: strip() and formattedRead()
On Wednesday, 21 March 2018 at 18:44:12 UTC, realhet wrote: Compiling this I get an error: "formattedRead: cannot deduce arguments from (string, string, float, float, float)" What compiler version are you using? The newest versions allow this code, though the old ones require an intermediate variable to satisfy the `ref` requirement on formattedRead (it will want to update that variable to advance it past the characters it read). so either update your version, or just give an and use an intermediate: string s = "".strip; formattedRead(s, )
Re: strip() and formattedRead()
On 03/21/2018 11:44 AM, realhet wrote:
float x,y,z;
if(formattedRead(" vertex -5.1 2.4 3.666".strip, "vertex %f %f
%f", x, y, z)){
writefln("v(%f, %f, %f)", x, y, z);
}
formattedRead wants to modify the source, so it takes it by reference,
which rvalues cannot be passed for. Make the source an lvalue (i.e. a
proper variable):
auto source = "vertex -5.1 2.4 3.666".strip;
if(formattedRead(source, "vertex %f %f %f", x, y, z)){
Ali
Re: How to use an associative array with array values.
On Wednesday, 21 March 2018 at 18:31:29 UTC, tipdbmp wrote:
I see. I guess the other would be:
{
int[8192] bar;
int[8192][string] foo;
foo["a"] = bar;
foo["a"][8191] = -1;
}
https://run.dlang.io/is/AK2X2t
Are you looking to use static arrays or dynamic? You can't use
the new keyword if it static.
strip() and formattedRead()
Hi,
I just got this problem and since an hour can't find answer to it.
float x,y,z;
if(formattedRead("vertex -5.1 2.4 3.666".strip, "vertex %f
%f %f", x, y, z)){
writefln("v(%f, %f, %f)", x, y, z);
}
Compiling this I get an error: "formattedRead: cannot deduce
arguments from (string, string, float, float, float)"
When I don't use .strip(), just a string literal or a string
variable it works good.
(It fails also when I'm using UFCS)
What did I do wrong?
Re: #import mapi.h
On Wednesday, 21 March 2018 at 16:22:45 UTC, Martin Tschierschke
wrote:
Is there an step by step introduction how to convert a C header
of an external lib into the right extern(C){} block?
A blog post or tutorial, or chapter in a D book? (I have those
from Packt Publishing)
(Especially I am trying to get this used with D:
Montetdb C-API
https://www.monetdb.org/Documentation/Manuals/SQLreference/Programming/MAPI
With:
https://github.com/snaga/monetdb/blob/master/clients/mapilib/mapi.h)
The page: https://dlang.org/spec/interfaceToC.html is known,
but not detailed enough for me.
The easiest thing to do is to write a wrapper in C. The wrapper
will include all necessary headers and provide some easy to use
functions that you can call from D. Of course, you'll need to use
a C compiler to compile it.
Anyway, this header looks very straightforwar, no particular
tricks with the preprocessor. It should be something like this
(untested, obviously):
import core.stdc.stdio : FILE;
enum
{
MAPI_AUTO = 0, /* automatic type detection */
MAPI_TINY = 1,
MAPI_UTINY = 2,
MAPI_SHORT = 3,
MAPI_USHORT= 4,
MAPI_INT = 5,
MAPI_UINT = 6,
MAPI_LONG = 7,
MAPI_ULONG = 8,
MAPI_LONGLONG = 9,
MAPI_ULONGLONG = 10,
MAPI_CHAR = 11,
MAPI_VARCHAR = 12,
MAPI_FLOAT = 13,
MAPI_DOUBLE= 14,
MAPI_DATE = 15,
MAPI_TIME = 16,
MAPI_DATETIME = 17,
MAPI_NUMERIC = 18,
}
enum int PLACEHOLDER = '?';
enum
{
MAPI_SEEK_SET = 0,
MAPI_SEEK_CUR = 1,
MAPI_SEEK_END = 2,
}
enum
{
MAPI_TRACE = 1,
MAPI_TRACE_LANG = 2,
}
alias MapiMsg = int;
enum
{
MOK = 0,
MERROR = -1,
MTIMEOUT= -2,
MMORE = -3,
MSERVER = -4,
}
enum
{
LANG_MAL= 0,
LANG_SQL= 2,
LANG_JAQL = 3,
}
/* prompts for MAPI protocol */
enum int PROMPTBEG = '\001'; /* start prompt bracket */
/* prompt: ready for new query */
const(char)* PROMPT1 = "\001\001\n".ptr;
/* prompt: more data needed */
const(char)* PROMTP2 = "\001\002\n".ptr;
/*
* The table field information is extracted from the table headers
* obtained from the server. This list may be extended in the
future.
* The type of both the 'param' and 'binding'
* variables refer to their underlying C-type. They are used for
* automatic type coercion between back-end and application.
*/
struct MapiStruct;
alias Mapi = MapiStruct*;
/* this definition is a straight copy from
sql/include/sql_query.h */
enum
{
Q_PARSE = 0,
Q_TABLE = 1,
Q_UPDATE= 2,
Q_SCHEMA= 3,
Q_TRANS = 4,
Q_PREPARE = 5,
Q_BLOCK = 6,
}
struct MapiStatement;
alias MapiHdl = MapiStatement*;
alias mapi_uint64 = ulong;
alias mapi_int64 = long;
/* three structures used for communicating date/time information
*/
/* these structs are deliberately compatible with the ODBC
versions
SQL_DATE_STRUCT, SQL_TIME_STRUCT, and SQL_TIMESTAMP_STRUCT */
/* used by MAPI_DATE */
struct MapiDate
{
short year;
ushort month;
ushort day;
}
/* used by MAPI_TIME */
struct MapiTime
{
ushort hour;
ushort minute;
ushort second;
}
/* used by MAPI_DATETIME */
struct MapiDateTime
{
short year;
ushort month;
ushort day;
ushort hour;
ushort minute;
ushort second;
uint fraction; /* in 1000 millionths of a second (10e-9) */
}
/* connection-oriented functions */
extern (C)
{
Mapi mapi_mapi(const char *host,
int port,
const char *username,
const char *password,
const char *lang,
const char *dbname);
// and so on...
}
Re: How to use an associative array with array values.
I see. I guess the other would be:
{
int[8192] bar;
int[8192][string] foo;
foo["a"] = bar;
foo["a"][8191] = -1;
}
Re: Template condition evaluation (shortcircuit)
On Wed, Mar 21, 2018 at 05:42:34PM +, rumbu via Digitalmars-d-learn wrote:
> I tried to define a template:
>
> enum isFoo(alias T) =
> T.stringof.length >= 3 && T.stringof[0..3] == "abc";
>
> int i;
> pragma(msg, isFoo!i);
>
> Error: string slice [0 .. 3] is out of bounds
> Error: template object.__equals cannot deduce function from argument types
> !()(string, string), candidates are:
> [...]
>
> Is it normal that the condition is not short circuited at first test?
> Of course, I can throw there a bunch of static ifs in an eponymous
> template, but I don't see the point of this verbosity.
[...]
The reason it's not short-circuited is because T.stringof[0..3] is
processed *before* the && is evaluated. Basically, this:
enum isFoo(alias T) = T.stringof.length >= 3 && T.stringof[0..3] ==
"abc";
is a shorthand for this:
template isFoo(alias T)
{
enum isFoo = T.stringof.length >= 3 && T.stringof[0..3] ==
"abc";
}
T.stringof[0..3] is actually evaluated during AST expansion time,
because it's slicing a template argument list, but && isn't evaluated
until CTFE-time.
See: https://wiki.dlang.org/User:Quickfur/Compile-time_vs._compile-time
Now, arguably, we *could* make it so that && is also shortcircuited at
AST expansion time, i.e., basically lower && in this context into a
series of nested static if's instead of a CTFE expression. But that
would probably involve some extensive changes in the compiler.
T
--
The trouble with TCP jokes is that it's like hearing the same joke over and
over.
Re: OK, I'm stumped on this one: dstep, struct, mixin, bitfields
On 03/21/2018 11:00 AM, Russel Winder wrote: > The code I am playing with generated by DStep involves lots of lots of > structs with mixin bitfields. All of them seem to compile file, except > one. How is it that: > > mixin(bitfields!( > ubyte, "current_next", 1, > ubyte, "version", 5, > ubyte, "one2", 2)); /* TS ID */ > > can result in the following error. The line for "version" is 141 and > the one for "one2" is 142. I think it's because 'version' is a D keyword. :) Ali
Re: OK, I'm stumped on this one: dstep, struct, mixin, bitfields
On Wednesday, 21 March 2018 at 18:00:38 UTC, Russel Winder wrote: ubyte, "version", 5, version is a D keyword, so I would suggest trying "version_" there instead and see if it works. (I'm guessing btw, the error message was way to long and illegible, but this is an easy first guess anyway)
OK, I'm stumped on this one: dstep, struct, mixin, bitfields
The code I am playing with generated by DStep involves lots of lots of
structs with mixin bitfields. All of them seem to compile file, except
one. How is it that:
mixin(bitfields!(
ubyte, "current_next", 1,
ubyte, "version", 5,
ubyte, "one2", 2)); /* TS ID */
can result in the following error. The line for "version" is 141 and
the one for "one2" is 142.
source/libdvbv5_d/header.d-mixin-139(141): Error: no identifier for declarator
`ubyte`
source/libdvbv5_d/header.d-mixin-139(141): Error: identifier or integer
expected inside version(...), not `)`
source/libdvbv5_d/header.d-mixin-139(141): Error: found `@` when expecting `)`
source/libdvbv5_d/header.d-mixin-139(141): Error: no identifier for declarator
`safe`
source/libdvbv5_d/header.d-mixin-139(141): Error: declaration expected, not
`return`
source/libdvbv5_d/header.d-mixin-139(142): Error: no identifier for declarator
`void`
source/libdvbv5_d/header.d-mixin-139(142): Error: identifier or integer
expected inside version(...), not `ubyte`
source/libdvbv5_d/header.d-mixin-139(142): Error: found `v` when expecting `)`
source/libdvbv5_d/header.d-mixin-139(142): Error: declaration expected, not `)`
source/libdvbv5_d/header.d-mixin-139(142): Error: declaration expected, not
`assert`
source/libdvbv5_d/header.d-mixin-139(142): Error: no identifier for declarator
`_current_next_version_one2`
source/libdvbv5_d/header.d-mixin-139(142): Error: declaration expected, not `=`
source/libdvbv5_d/header.d(139): Error: incomplete mixin declaration `"private
ubyte _current_next_version_one2;@property ubyte current_next() @safe pure
nothrow @nogc const { auto result = (_current_next_version_one2 & 1U) >>0U;
return cast(ubyte) result;}\x0a@property void current_next(ubyte v) @safe pure
nothrow @nogc { assert(v >= current_next_min, \"Value is smaller than the
minimum value of bitfield 'current_next'\"); assert(v <= current_next_max,
\"Value is greater than the maximum value of bitfield 'current_next'\");
_current_next_version_one2 = cast(typeof(_current_next_version_one2))
((_current_next_version_one2 & (-1-cast(typeof(_current_next_version_one2))1U))
| ((cast(typeof(_current_next_version_one2)) v << 0U) & 1U));}\x0aenum ubyte
current_next_min = cast(ubyte)0U; enum ubyte current_next_max = cast(ubyte)1U;
@property ubyte version() @safe pure nothrow @nogc const { auto result =
(_current_next_version_one2 & 62U) >>1U; return cast(ubyte)
result;}\x0a@property void version(ubyte v) @safe pure nothrow @nogc { assert(v
>= version_min, \"Value is smaller than the minimum value of bitfield
'version'\"); assert(v <= version_max, \"Value is greater than the maximum
value of bitfield 'version'\"); _current_next_version_one2 =
cast(typeof(_current_next_version_one2)) ((_current_next_version_one2 &
(-1-cast(typeof(_current_next_version_one2))62U)) |
((cast(typeof(_current_next_version_one2)) v << 1U) & 62U));}\x0aenum ubyte
version_min = cast(ubyte)0U; enum ubyte version_max = cast(ubyte)31U;
@property ubyte one2() @safe pure nothrow @nogc const { auto result =
(_current_next_version_one2 & 192U) >>6U; return cast(ubyte)
result;}\x0a@property void one2(ubyte v) @safe pure nothrow @nogc { assert(v >=
one2_min, \"Value is smaller than the minimum value of bitfield 'one2'\");
assert(v <= one2_max, \"Value is greater than the maximum value of bitfield
'one2'\"); _current_next_version_one2 =
cast(typeof(_current_next_version_one2)) ((_current_next_version_one2 &
(-1-cast(typeof(_current_next_version_one2))192U)) |
((cast(typeof(_current_next_version_one2)) v << 6U) & 192U));}\x0aenum ubyte
one2_min = cast(ubyte)0U; enum ubyte one2_max = cast(ubyte)3U; "`
--
Russel.
===
Dr Russel Winder t: +44 20 7585 2200
41 Buckmaster Roadm: +44 7770 465 077
London SW11 1EN, UK w: www.russel.org.uk
signature.asc
Description: This is a digitally signed message part
Template condition evaluation (shortcircuit)
I tried to define a template: enum isFoo(alias T) = T.stringof.length >= 3 && T.stringof[0..3] == "abc"; int i; pragma(msg, isFoo!i); Error: string slice [0 .. 3] is out of bounds Error: template object.__equals cannot deduce function from argument types !()(string, string), candidates are: [...] Is it normal that the condition is not short circuited at first test? Of course, I can throw there a bunch of static ifs in an eponymous template, but I don't see the point of this verbosity.
Re: #import mapi.h
On Wednesday, 21 March 2018 at 16:22:45 UTC, Martin Tschierschke
wrote:
Is there an step by step introduction how to convert a C header
of an external lib into the right extern(C){} block?
A blog post or tutorial, or chapter in a D book? (I have those
from Packt Publishing)
While googling I found this:
https://dlang.org/blog/2017/12/05/interfacing-d-with-c-getting-started/
Haven't read it yet, but might give you some more insight.
For automatic conversion I stumbled across Dstep which I so far
like a lot:
https://github.com/jacob-carlborg/dstep
Re: Manipulate slice or specific element of range and return range
On Wednesday, 21 March 2018 at 12:07:49 UTC, Simen Kjærås wrote:
On Wednesday, 21 March 2018 at 11:30:28 UTC, Timoses wrote:
unittest {
assert("my capitalized string".capitalize ==
"myCapitalizedString");
}
auto capitalize(string s) {
import std.regex, std.uni;
return s.replaceAll!(a => a[1].toUpper)(regex(" (.)"));
}
Ty! This definitely put me on the right track regarding strings.
Re: Manipulate slice or specific element of range and return range
On Wednesday, 21 March 2018 at 12:53:56 UTC, Ali Çehreli wrote:
Here is another one that uses ForwardRange.
import std.range; // empty, take, save, chain, popFrontN;
import std.uni; // asLowerCase;
import std.algorithm; // equal, filter;
import std.conv; // text;
auto initialLowerCased(R)(R str, size_t N = 1) {
if (str.empty) {
N = 0;
}
auto frontPart = str.take(N);
auto rest = str.save;
rest.popFrontN(N);
return chain(frontPart.asLowerCase, rest);
}
unittest {
assert(initialLowerCased("My Test String", 4).equal("my
test String"));
assert(initialLowerCased("").equal(""));
}
auto foo(R)(R str) {
return str.filter!(c => c != ' ').initialLowerCased;
}
void main() {
auto result = foo("My Capital String");
// result above is a range. std.conv.text can make a string:
string lower = result.text;
assert(lower == "myCapitalString");
}
Ali
I like it! I remember having a similar situation another time
where it was not about strings. I wonder why there is no method
for this in the standard library that can execute a predicate on
specific elements of a range..
Re: #import mapi.h
Martin Tschierschke wrote: or tutorial ok, tutorial: 1. learn C. 2. learn D. 3. DO IT! ;-)
#import mapi.h
Is there an step by step introduction how to convert a C header
of an external lib into the right extern(C){} block?
A blog post or tutorial, or chapter in a D book? (I have those
from Packt Publishing)
(Especially I am trying to get this used with D:
Montetdb C-API
https://www.monetdb.org/Documentation/Manuals/SQLreference/Programming/MAPI
With:
https://github.com/snaga/monetdb/blob/master/clients/mapilib/mapi.h)
The page: https://dlang.org/spec/interfaceToC.html is known, but
not detailed enough for me.
Re: Incomprehensible error message
On Tue, 2018-03-20 at 14:18 -0700, H. S. Teoh via Digitalmars-d-learn wrote: > […] > > Either way, it will require a lot of effort to pull off. > As Rust has shown appreciating that the quality of the error messages define the quality of the compiler, the quality of the error message from rustc are now very good indeed. On the other hand Rust has a lot of paid staff. -- Russel. === Dr Russel Winder t: +44 20 7585 2200 41 Buckmaster Roadm: +44 7770 465 077 London SW11 1EN, UK w: www.russel.org.uk signature.asc Description: This is a digitally signed message part
Re: Packages and module import
On Tue, 2018-03-20 at 22:08 +0100, Jacob Carlborg via Digitalmars-d- learn wrote: > […] > Not sure if this will help, but are you aware that DStep can add a > package to the module declaration using "--package"? No I wasn't. And it works a treat. -- Russel. === Dr Russel Winder t: +44 20 7585 2200 41 Buckmaster Roadm: +44 7770 465 077 London SW11 1EN, UK w: www.russel.org.uk signature.asc Description: This is a digitally signed message part
Re: How to use an associative array with array values.
On Wednesday, 21 March 2018 at 15:53:32 UTC, tipdbmp wrote:
int[10][string] foo;
One option is to initialize like this
---
void main() {
int[10][string] foo;
if("a" !in foo)
foo["a"] = [0,0,0,0,0,0,0,0,0,0]; // set all to zero to create
the key
foo["a"][4] = 4; // now valid to set individual element
}
---
How to use an associative array with array values.
// foo is an associative array/hashtable with // key type: string // value type: int[10] // int[10][string] foo; // foo["a"] = new int[10]; // Range violation at runtime // foo["a"][0] = 1; // Range violation at runtime
Issue with traits usability
Hi!
How do I get past this?
static struct X {
int x;
private enum T = 1;
private alias M = string;
}
foreach (Member; __traits(allMembers, X)) {
pragma(msg, __traits(getProtection, __traits(getMember, X,
Member)));
}
Output:
public
private
c.d(1084): Error: argument string has no protection
c.d(1084):while evaluating pragma(msg,
__traits(getProtection, string))
What I want to achieve essentially is skip all X's aliases and
templates, but get everything else, like enums and data members.
How would I go about this in a robust way?
I actually want to skip aliases, and templates.
How Does Language Interpretation Take Place In United Nations?
You may be wondering whether the United Nations employ an interpreter for all dialects across the globe. It does not do so as the presenters at the UN should make their dose he's in any one of its 6 official languages, These official languages are Spanish, French, English, Chinese, Arabic, and Russian. The interpreters of the United Nations then translate the speech into all other 5 official languages. In case a presenter does not use any of these 6 languages either because he or she is unaware of these languages or to make a political statement, they need to also bring an interpreter of their own. The said interpreter then has to translate the presentation into any of the official languages like French or English. The other interpreters then translate from that particular translation. There is another alternative before the speaker. They are permitted to submit a written translation of the speech being made by him or her in any official language provided their speech do not deviate from the written text. The UN makes use of simultaneous interpretation that signifies that all translations rake place instantly without any break. It is contrary to consecutive interpretation where the translator and the speaker speak alternately. The interpretation service of the United Nations always has 12.interpreters who work in six different booths. Each booth is dedicated to one official language. Both the interpreters sitting in its English booth translate in English while the French booth interpreters translate the presentation into French and so on. www.language-school.hk www.language-school.sg
Re: Slow start up time of runtime (correction: Windows real-time protection)
On Tuesday, 20 March 2018 at 16:56:59 UTC, Dennis wrote: On Tuesday, 20 March 2018 at 12:18:16 UTC, Adam D. Ruppe wrote: On Tuesday, 20 March 2018 at 09:44:41 UTC, Dennis wrote: This now leaves the question what's the best way to mitigate this, because I would gladly get rid of the second of delay any time I invoke dmd, ldc or dub as well as my own applications. In Windows Security Center Settings (where you can disable realtime scan) there is also an entry "Exclusions" (in german windows "Ausschlüsse"). I added exclusions for the folder, where I installed dmd and ldc and I added an exclusion for the folder, where I compile my D programs. Now startup of dmd and freshly compiled programs is fast again.
Re: Manipulate slice or specific element of range and return range
On 03/21/2018 04:30 AM, Timoses wrote:
Hey,
I'm struggling to find a way to achieve this. I've looked through
std.algorithm but didn't find anything.. Maybe I'm blind.
What I would like to do is filter out all spaces in a string and change
the front letter to lower case:
string m = "My Capital String";
string lower = m
.filter!(c => c != ' ')
.!(0, c => c.toLower) // executeAt does not exist
.array.to!string;
assert(lower == "myCapitalString");
or sth like
m.filter!(...)
.map!((element, int index) {
if (index == 0)
return element.toLower;
else
break; // stop since we are done manipulating range
});
Anyway to do this?
Here is another one that uses ForwardRange.
import std.range; // empty, take, save, chain, popFrontN;
import std.uni; // asLowerCase;
import std.algorithm; // equal, filter;
import std.conv; // text;
auto initialLowerCased(R)(R str, size_t N = 1) {
if (str.empty) {
N = 0;
}
auto frontPart = str.take(N);
auto rest = str.save;
rest.popFrontN(N);
return chain(frontPart.asLowerCase, rest);
}
unittest {
assert(initialLowerCased("My Test String", 4).equal("my test String"));
assert(initialLowerCased("").equal(""));
}
auto foo(R)(R str) {
return str.filter!(c => c != ' ').initialLowerCased;
}
void main() {
auto result = foo("My Capital String");
// result above is a range. std.conv.text can make a string:
string lower = result.text;
assert(lower == "myCapitalString");
}
Ali
Re: Static Arrays: Behaviour of Passing & Returning
On Wednesday, 21 March 2018 at 12:01:01 UTC, Quantum Nerd wrote: How is it possible that b in main() and r in the function occupy the same memory? I would expect the same behaviour as with c. Can somebody with more experience shed some light on this? I'm pretty sure you're seeing NRVO - Named Return Value Optimization. Also called copy elision: https://en.wikipedia.org/wiki/Copy_elision The compiler sees that when you return r, it's immediately assigned to b. Since it's a waste of cycles to allocate twice and copy the values, the function is told where the result will end up, and writes it there immediately. The reason you don't see that with c is that the compiler isn't very smart, especially not with optimizations turned off, so it doesn't know for sure that it can safely overwrite the values already in c at that point. -- Simen
Re: Manipulate slice or specific element of range and return range
On Wednesday, 21 March 2018 at 11:30:28 UTC, Timoses wrote:
Hey,
I'm struggling to find a way to achieve this. I've looked
through std.algorithm but didn't find anything.. Maybe I'm
blind.
What I would like to do is filter out all spaces in a string
and change the front letter to lower case:
https://xkcd.com/208/
unittest {
assert("my capitalized string".capitalize ==
"myCapitalizedString");
}
auto capitalize(string s) {
import std.regex, std.uni;
return s.replaceAll!(a => a[1].toUpper)(regex(" (.)"));
}
--
Simen
Static Arrays: Behaviour of Passing & Returning
Hello everybody,
I am fairly new to the D language,
and I've been trying to understand the behaviour
of passing arrays to functions, especially also
static arrays.
There is an example that puzzles me:
import std.stdio;
double[3] sqr( double[3] v ) {
double[3] r;
writefln( "v (%20s) : %s", typeof(v).stringof, [0] );
writefln( "r (%20s) : %s", typeof(r).stringof, [0] );
r[] = v[] * v[];
return r;
}
void main() {
double[3] a = [1.0, 2.0, 3.0 ];
double[3] b = sqr(a);
writefln( "a (%20s) : %s", typeof(a).stringof, [0] );
writefln( "b (%20s) : %s", typeof(b).stringof, [0] );
double[3] c; c = sqr(a);
writefln( "c (%20s) : %s", typeof(c).stringof, [0] );
}
with the output:
v ( double[3]) : 7FFD0D3874E0
r ( double[3]) : 7FFD0D387548
a ( double[3]) : 7FFD0D387528
b ( double[3]) : 7FFD0D387548
v ( double[3]) : 7FFD0D3874E0
r ( double[3]) : 7FFD0D387588
c ( double[3]) : 7FFD0D387568
According to the documentation, static arrays are of value type.
How is it possible that b in main() and r in the function occupy
the same memory?
I would expect the same behaviour as with c.
Can somebody with more experience shed some light on this?
Thanks in advance,
qnerd
Manipulate slice or specific element of range and return range
Hey,
I'm struggling to find a way to achieve this. I've looked through
std.algorithm but didn't find anything.. Maybe I'm blind.
What I would like to do is filter out all spaces in a string and
change the front letter to lower case:
string m = "My Capital String";
string lower = m
.filter!(c => c != ' ')
.!(0, c => c.toLower) // executeAt does not
exist
.array.to!string;
assert(lower == "myCapitalString");
or sth like
m.filter!(...)
.map!((element, int index) {
if (index == 0)
return element.toLower;
else
break; // stop since we are done manipulating
range
});
Anyway to do this?
Re: Is there a way to pipeline program with random-access ranges in C#?
On Wednesday, 21 March 2018 at 07:40:01 UTC, Dukc wrote: ...except that IEnumerables cannot popBack(), so can only do that by doing an additional copy and reversing that. But I quess there's no better alternative, short of doing it C-style... A random access range would be represented as IList, backward iteration can be just a part of chunking.
Re: Is there a way to pipeline program with random-access ranges in C#?
On Tuesday, 20 March 2018 at 15:57:16 UTC, Kagamin wrote: On Tuesday, 20 March 2018 at 15:06:14 UTC, Dukc wrote: Won't quite do it, because that would not iterate backwards. Linq has no chunking, so you would need to write it, maybe similar to SelectMany, but with the opposite meaning. ...except that IEnumerables cannot popBack(), so can only do that by doing an additional copy and reversing that. But I quess there's no better alternative, short of doing it C-style... If you want to have index, there's https://msdn.microsoft.com/en-us/library/bb534869(v=vs.110).aspx Wow, didn't know that. Thanks, It'll be useful.
Re: recursive template expansion: Why does this not compile?
On 03/21/2018 01:47 AM, Ontonator wrote:
The following code does not compile:
void main() {}
class SuperClass {}
class TemplatedClass(T : SuperClass) {}
class A : SuperClass {
alias T = TemplatedClass!B;
}
class B : SuperClass {
alias T = TemplatedClass!C;
}
class C : SuperClass {}
It gives the error:
test.d(12): Error: class `test.TemplatedClass(T : SuperClass)`
recursive template expansion
test.d(12): while looking for match for TemplatedClass!(C)
The aliases do not have to be aliases, as long as there is some
reference to the class (e.g. method and variable declarations also
work). What exactly is the reason for this error?
Compiler bug. It works when you move the declaration of `B` before the
one of `A`. Order shouldn't matter there.
