Re: Real OOP with D
On Monday, 17 August 2015 at 05:57:52 UTC, Ozan wrote:
Hi
Working with objectoriented concepts results often in large
trees of related classes. Every instance of a class knows his
methods and data. An example like following would work:
import std.stdio;
class Family { }
class Dad : Family { void greeting() { writeln("I'm dad"); } }
class Boy : Family { void greeting() { writeln("I'm daddy's
boy"); } }
void main() {
writeln("Father and son");
Dad father = new Dad;
Family son = new Boy;
father.greeting;
son.greeting;
}
The critical point is using a variable of type Family for an
instance of Boy. Class Family covers the greeting method of
Boy. In real OOP that would not be a problem, because the
access point of view starts with the object. In D, it starts
with the class definition.
Is there any way to get real OOP with D?
Regards, Ozan
Can you name an OOP oriented language that allows this ? Your
example is eroneous OOP.
The 2 other answers you 've got (the first using an interface and
the second using an abstract class) are valid OOP.
One of the fundamental concept OOP is that a function defined in
a class exists also in its subclasses. So how do you expect
`greeting()` to exist in Family if it's only defined in its
sub-classes ?
You can verify that with the 'Liskov substitution principle'
(https://en.wikipedia.org/wiki/Liskov_substitution_principle).
Actually your sample violates this principle.
Re: How to provide this arg or functor for algorithm?
On Sunday, 16 August 2015 at 23:05:42 UTC, Ali Çehreli wrote:
// Now the type of d is a template parameter
@nogc auto func(Func)(uint[] arr, Func d)
{
return arr.map!(d);
}
Huh. I think func being a template is the key here. When the
original code is put in a template, it works too (with 2.068):
void func()() @nogc
{
import std.algorithm;
uint[3] arr = [1,2,3];
uint context = 2;
auto r = arr[].map!(delegate(value) { return value * context;
});
}
void main()
{
func();
}
Re: How to provide this arg or functor for algorithm?
On Monday, 17 August 2015 at 09:51:47 UTC, anonymous wrote: Huh. I think func being a template is the key here. When the original code is put in a template, it works too (with 2.068): Nope, it "works" only because "r" is unreferenced and gets thrown out. Just try using r.front there, for example, and the error returns.
Re: Theoretical Best Practices
On 8/14/15 6:25 PM, DarthCthulhu wrote:
On Friday, 14 August 2015 at 12:40:08 UTC, Steven Schveighoffer wrote:
I would do it this way:
// at module level
debug(logging) {
Logger logger;
static this() { logger = new Logger;}
}
By 'module level', I assume you mean in the module that defines the
Logger class? An 'import debug.logger' or somesuch would then give all
relevant modules access, correct?
I mean, in global scope (which is defined as being part of the module).
Not inside a class/struct/function.
Is the compiler smart enough to compile out all the symbols associated
with the logger if it is never instantiated?
If it's never instantiated, and it's a template, then it will not be
compiled in.
If it's not a template, it could potentially make it into the binary.
-Steve
Re: How to provide this arg or functor for algorithm?
On Monday, 17 August 2015 at 10:28:33 UTC, thedeemon wrote:
Nope, it "works" only because "r" is unreferenced and gets
thrown out. Just try using r.front there, for example, and the
error returns.
You're right, it falls short.
But I think r not being referenced is not exactly it. Using front
in Ali's func breaks it in the same way. And returning r from
func works.
Wait, returning r from func works? Yes:
auto func()(uint[] arr, uint context) @nogc
{
import std.algorithm;
auto r = arr[].map!(delegate(value) { return value * context;
});
return r;
}
void main() @nogc
{
uint[3] arr = [1,2,3];
uint context = 2;
auto r = func(arr[], context);
import std.algorithm: equal;
import std.range: only;
assert(equal(r, only(2, 4, 6)));
}
Is that supposed to compile? A closure is needed for the
delegate, isn't it? With @nogc, where is the closure stored? This
looks like an accepts-invalid bug to me.
It doesn't compile when func is not a template. So maybe the
check is broken for templates.
It also doesn't compile with 2.067, so this may be a regression.
Coming back to Ali's code, here's a version that shows that func
doesn't need template parameters, but it needs to be a template:
import std.stdio;
import std.algorithm;
struct Caller
{
uint method(uint value) pure @nogc {
return _context * value;
}
uint _context;
}
auto func()(uint[] arr, uint delegate(uint) pure @nogc d) @nogc
{
return arr.map!(d);
}
void main() @nogc
{
uint[3] arr = [1,2,3];
uint context = 2;
auto c = Caller(context);
auto d = &c.method;
auto r = func(arr[], d);
import std.algorithm: equal;
import std.range: only;
assert(equal(r, only(2, 4, 6)));
}
I think this relies on the same discrepancy as the problematic
code above.
std.net.curl
Hi,
I'm trying to compile this trivial example of std.net.curl:
// app.d
import std.stdio;
import std.net.curl;
void main() {
auto content = get("dlang.org");
}
Hovewer, "dmd app.d" spits a whole bunch of strange error
messages:
/usr/lib64/libphobos2.a(curl.o): In function
`_D3std3net4curl4HTTP21_sharedStaticCtor1520FZv':
std/net/curl.d:(.text._D3std3net4curl4HTTP21_sharedStaticCtor1520FZv+0xf):
undefined reference to `curl_version_info'
/usr/lib64/libphobos2.a(curl.o): In function
`_D3std3net4curl4Curl21_sharedStaticCtor1522FZv':
std/net/curl.d:(.text._D3std3net4curl4Curl21_sharedStaticCtor1522FZv+0xa):
undefined reference to `curl_global_init'
/usr/lib64/libphobos2.a(curl.o): In function
`_D3std3net4curl4Curl21_sharedStaticDtor1523FZv':
std/net/curl.d:(.text._D3std3net4curl4Curl21_sharedStaticDtor1523FZv+0x5):
undefined reference to `curl_global_cleanup'
/usr/lib64/libphobos2.a(curl_1ca7_192.o): In function
`_D3std3net4curl4HTTP4Impl6__dtorMFZv':
std/net/curl.d:(.text._D3std3net4curl4HTTP4Impl6__dtorMFZv+0x19):
undefined reference to `curl_slist_free_all'
/usr/lib64/libphobos2.a(curl_1cca_ea.o): In function
`_D3std3net4curl3FTP4Impl6__dtorMFZv':
std/net/curl.d:(.text._D3std3net4curl3FTP4Impl6__dtorMFZv+0x18):
undefined reference to `curl_slist_free_all'
/usr/lib64/libphobos2.a(curl_1cca_ea.o): In function
`_D3std3net4curl3FTP3dupMFZS3std3net4curl3FTP':
std/net/curl.d:(.text._D3std3net4curl3FTP3dupMFZS3std3net4curl3FTP+0xab):
undefined reference to `curl_slist_append'
/usr/lib64/libphobos2.a(curl_1cca_ea.o): In function
`_D3std3net4curl3FTP13clearCommandsMFZv':
std/net/curl.d:(.text._D3std3net4curl3FTP13clearCommandsMFZv+0x20): undefined
reference to `curl_slist_free_all'
/usr/lib64/libphobos2.a(curl_1cca_ea.o): In function
`_D3std3net4curl3FTP10addCommandMFAxaZv':
std/net/curl.d:(.text._D3std3net4curl3FTP10addCommandMFAxaZv+0x67): undefined
reference to `curl_slist_append'
/usr/lib64/libphobos2.a(curl_1ccf_432.o): In function
`_D3std3net4curl4Curl10initializeMFZv':
std/net/curl.d:(.text._D3std3net4curl4Curl10initializeMFZv+0x3d):
undefined reference to `curl_easy_init'
/usr/lib64/libphobos2.a(curl_1cd0_149.o): In function
`_D3std3net4curl4Curl3dupMFZS3std3net4curl4Curl':
std/net/curl.d:(.text._D3std3net4curl4Curl3dupMFZS3std3net4curl4Curl+0x25):
undefined reference to `curl_easy_duphandle'
/usr/lib64/libphobos2.a(curl_1cd4_37c.o): In function
`_D3std3net4curl4Curl8shutdownMFZv':
std/net/curl.d:(.text._D3std3net4curl4Curl8shutdownMFZv+0x1a):
undefined reference to `curl_easy_cleanup'
/usr/lib64/libphobos2.a(curl_1cd6_14c.o): In function
`_D3std3net4curl4Curl3setMFE3etc1c4curl10CurlOptionAxaZv':
std/net/curl.d:(.text._D3std3net4curl4Curl3setMFE3etc1c4curl10CurlOptionAxaZv+0x5d):
undefined reference to `curl_easy_setopt'
/usr/lib64/libphobos2.a(curl_1cd7_14c.o): In function
`_D3std3net4curl4Curl3setMFE3etc1c4curl10CurlOptionlZv':
std/net/curl.d:(.text._D3std3net4curl4Curl3setMFE3etc1c4curl10CurlOptionlZv+0x2e):
undefined reference to `curl_easy_setopt'
/usr/lib64/libphobos2.a(curl_1cd8_14c.o): In function
`_D3std3net4curl4Curl3setMFE3etc1c4curl10CurlOptionPvZv':
std/net/curl.d:(.text._D3std3net4curl4Curl3setMFE3etc1c4curl10CurlOptionPvZv+0x2e):
undefined reference to `curl_easy_setopt'
/usr/lib64/libphobos2.a(curl_1cd9_207.o): In function
`_D3std3net4curl4Curl5clearMFE3etc1c4curl10CurlOptionZv':
std/net/curl.d:(.text._D3std3net4curl4Curl5clearMFE3etc1c4curl10CurlOptionZv+0x28):
undefined reference to `curl_easy_setopt'
/usr/lib64/libphobos2.a(curl_1cda_67c.o): In function
`_D3std3net4curl4Curl16clearIfSupportedMFE3etc1c4curl10CurlOptionZv':
std/net/curl.d:(.text._D3std3net4curl4Curl16clearIfSupportedMFE3etc1c4curl10CurlOptionZv+0x28):
undefined reference to `curl_easy_setopt'
/usr/lib64/libphobos2.a(curl_1cdb_2fb.o): In function
`_D3std3net4curl4Curl7performMFE3std8typecons41__T4FlagVAyaa12_7468726f774f6e4572726f72Z4FlagZi':
std/net/curl.d:(.text._D3std3net4curl4Curl7performMFE3std8typecons41__T4FlagVAyaa12_7468726f774f6e4572726f72Z4FlagZi+0x22):
undefined reference to `curl_easy_perform'
/usr/lib64/libphobos2.a(curl_1cb0_65b.o): In function
`_D3std3net4curl4HTTP16addRequestHeaderMFAxaAxaZv':
std/net/curl.d:(.text._D3std3net4curl4HTTP16addRequestHeaderMFAxaAxaZv+0x11b):
undefined reference to `curl_slist_append'
/usr/lib64/libphobos2.a(curl_1cd2_4a1.o): In function
`_D3std3net4curl4Curl11errorStringMFiZAya':
std/net/curl.d:(.text._D3std3net4curl4Curl11errorStringMFiZAya+0x11): undefined
reference to `curl_easy_strerror'
collect2: error: ld returned 1 exit status
--- errorlevel 1
DMD 2.068.0, openSUSE 13.2 x64
I'm absolutely sure that I have licurl installed. "zypper info
libcurl4" shows me that it's version is 7.43.0-2.1
Re: std.net.curl
On Monday, 17 August 2015 at 12:52:37 UTC, tired_eyes wrote: Hovewer, "dmd app.d" spits a whole bunch of strange error messages: try "dmd -lcurl app.d" and see if that helps.
Re: std.net.curl
On Monday, 17 August 2015 at 12:58:54 UTC, Adam D. Ruppe wrote: On Monday, 17 August 2015 at 12:52:37 UTC, tired_eyes wrote: Hovewer, "dmd app.d" spits a whole bunch of strange error messages: try "dmd -lcurl app.d" and see if that helps. Error: unrecognized switch '-lcurl'
Re: std.net.curl
On Monday, 17 August 2015 at 13:04:31 UTC, tired_eyes wrote: On Monday, 17 August 2015 at 12:58:54 UTC, Adam D. Ruppe wrote: On Monday, 17 August 2015 at 12:52:37 UTC, tired_eyes wrote: Hovewer, "dmd app.d" spits a whole bunch of strange error messages: try "dmd -lcurl app.d" and see if that helps. Error: unrecognized switch '-lcurl' do you use dub? if so, did you add "libs": ["curl"] to your dub.json? if that doesn't help, please post the output of curl-config. e.g. curl-config --libs --built-shared --prefix --static-libs
Re: std.net.curl
On Monday, 17 August 2015 at 12:58:54 UTC, Adam D. Ruppe wrote: On Monday, 17 August 2015 at 12:52:37 UTC, tired_eyes wrote: Hovewer, "dmd app.d" spits a whole bunch of strange error messages: try "dmd -lcurl app.d" and see if that helps. DMD does not accept -lcurl. From dmd --help: -Llinkerflag pass linkerflag to link ergo dmd -L-lcurl app.d on my machine (64Bit linux mint 17.2 with libcurl4-openssl-dev installed) -L-lcurl reduces the number of linker errors but the example still fails. I run dmd -c app.d dmd -L-lcurl app.o -v and figured out that the linker is invoked (on my machine) with gcc a.o -o a -m64 -lcurl -L/usr/lib/x86_64-linux-gnu -Xlinker --export-dynamic -l:libphobos2.a -lpthread -lm -lrt If I change the order of the libraries (move -lcurl to the end), it links. Used commands: dmd -c app.d gcc app.o -o app -m64 -L/usr/lib/x86_64-linux-gnu -Xlinker --export-dynamic -l:libphobos2.a -lpthread -lm -lrt -lcurl (the later may be different on OpenSUSE (?) - better check with dmd -v ...)
Re: std.net.curl
On Monday, 17 August 2015 at 13:13:48 UTC, anonymous wrote: and figured out that the linker is invoked (on my machine) with gcc a.o -o a -m64 -lcurl -L/usr/lib/x86_64-linux-gnu -Xlinker correct (I named the example programm a.d instead of app.d): gcc app.o -o app -m64 -lcurl -L/usr/lib/x86_64-linux-gnu -Xlinker This issue is already known: https://issues.dlang.org/show_bug.cgi?id=12572 and https://issues.dlang.org/show_bug.cgi?id=7044
Re: Pointers to Dynamic Arrays
On Monday, 17 August 2015 at 03:07:26 UTC, Adam D. Ruppe wrote:
On Monday, 17 August 2015 at 02:45:22 UTC, Brandon Ragland
wrote:
[...]
Short answer: pointers to slices are usually a mistake, you
probably don't actually want it, but rather should be using a
regular slice instead.
[...]
Here, for example, you've accidentally escaped slice land and
are unto unchecked pointer arithmetic.
Since file is declared char[]* instead of char[], indexing it
works C style: it at the index as an offset from the base
char[].
In other words, it works more as if you wrote `char** file` in
C. (still not identically, a D slice is different than a C
char*, but same idea).
The above will only really work fine for index 0. Anything else
would be a wild pointer. If this didn't crash on you, you just
got kinda lucky with the index.
The append compiles because dereferencing a `char[]*` yields a
`char[]`, which D can append normally.
[...]
This errors for the same reason the top one succeeded: what's
pointed to by a char[]* is char[], not char. So you are trying
to compare a string on the left hand side to an individual
character on the right hand side.
In other words, what your error message told :)
[...]
char[] in D is like:
struct char_array {
size_t length;
char* ptr;
}
in C. Since there's already a pointer in there, you typically
don't want the address of this struct, you just want to pass it
right down by value and let the pointer be copied (it still
points to the same actual data).
BTW you can access those .length and .ptr values in D:
char[] slice;
char* a = slice.ptr; // works
The only time you'd actually want a char[]* in D is if you need
to write back to the original *variable* once you append or
shrink it. (The contents are fine, they can be modified through
the slice with no special effort.)
Bottom line again is char[] in D is like char* in C. So char[]*
in D is more like char** in C.
Thanks Adam.
I keep getting myself confused with D, when I'm thinking in C
land. Breaking it down like that is extremely helpful.
Going off what you're saying, this signature:
method(char[] file)
Would only copy the _pointer_, as this is similar to the C style
struct you mentioned:
struct char_array {
size_t len;
char* index;
}
If that is true, than passing it as _char[] file_ makes the most
sense to me. A pointer copy doesn't hurt as bad as an array copy,
of say, 100Kibibytes...
-Brandon
Re: std.net.curl
On Monday, 17 August 2015 at 13:04:31 UTC, tired_eyes wrote: Error: unrecognized switch '-lcurl' ooh I'm sorry, should have been `dmd -L-lcurl yourprogram.d`
Re: std.net.curl
On Monday, 17 August 2015 at 13:26:29 UTC, Adam D. Ruppe wrote: On Monday, 17 August 2015 at 13:04:31 UTC, tired_eyes wrote: Error: unrecognized switch '-lcurl' ooh I'm sorry, should have been `dmd -L-lcurl yourprogram.d` Yes, it did the trick.
Re: Pointers to Dynamic Arrays
On Monday, 17 August 2015 at 13:27:19 UTC, Brandon Ragland wrote:
If that is true, than passing it as _char[] file_ makes the
most sense to me. A pointer copy doesn't hurt as bad as an
array copy, of say, 100Kibibytes...
Right.
Knowing this helps to explain a lot btw:
char[] foo;
void func(char[] arg) {
}
func(foo);
In that scenario, foo's data is not copied, just a pointer to it
is. Very fast operation.
arg[0] = 'a';
Since it is a pointer, writing to the arg will also write to foo.
BUT:
arg = "a new thing";
This will NOT be seen outside. It wrote a new pointer to the
local variable arg's pointer, so now arg and foo point to
different data.
Similarly:
arg ~= 'a';
will not be seen outside. The pointer might change which is not
seen outside, and the length will change, which is also not seen.
So char[] arg in D is similar to char* arg_ptr, size_t length_ptr
in C - changing them inside the function just modifies local
variables, not the outer variable. Writing *through the pointer
will be seen outside though since they talk to the same data.
Similarly, slicing in D is just a pointer assignment:
char[] a = b[3 .. 4];
That's like in C:
a.ptr = b.ptr + 3;
a.length = 4-3;
Just basic arithmetic and assignment, no data copy going on.
This is all talking about T[] slices. Static arrays, in the form
of T[constant], are different:
ubyte[4] static_data;
void slice_test(ubyte[] slice) {}
void static_test(ubyte[4] copy) {}
slice_test(static_data[]); // passes a pointer to the data
static_test(static_data); // passes a copy.
So T[] is always talking about pointer+length, but T[n] is always
talking about a block of memory which is copied around to other
T[n].
Putting the [] at the end of it, like I did with slice_test,
fetches a pointer instead of copying. It is how you convert a
static memory chunk to a pointer.
There's a few more things but you should understand it now, apply
the low level principles to it and it all should make sense.
More reading:
http://dlang.org/d-array-article.html
http://dlang.org/arrays.html
Compiletime Vs Runtime bencmarks
Hello everyone . I need advice on my first D-project . I have uploaded it at :- https://bitbucket.org/mrjohns/matcher/downloads IDEA : Benchmarking of 3 runtime algorithms and comparing them to their compile-time variants. The only difference between these is that for the compile time-ones, the lookup tables (i.e. Arrays bmBc, bmGs, and suffixes ) must be computed at compile time( I currently rely on CTFE ) . While for the runtime-ones the lookup tables are computed on runtime. NB : The pattern matching algorithms themselves need not be executed at compile-time, only the lookup tables.Having stated this the algorithms which run on known( compile-time computed) tables must be faster than the ones which have to compute them at runtime. My results seem to show something different, only the first pair( BM_Runtime and BM_Compile-time) yields admissible results, the other two pair give higher execution time for the compile-time variants. I think am missing something here. Please help. Current Results for the pattern="GCAGAGAG" are as below :- BM_Runtime = 366 hnsecs position= 513 BM_Compile-time = 294 hnsecs position =513 BMH_Runtime = 174 hnsecs position= 513 BMH_Compile-time= 261 hnsecs position= 513 AG_Run-time = 258 hnsecsposition= 513 AG_Compile-time = 268 hnsecsposition= 513 Running the code : dmd -J. matcher.d inputs.d rtime_pre.d ctime_pre.d && numactl --physcpubind=0 ./matcher I would appreciate your suggestions. Regards,
Re: Compiletime Vs Runtime bencmarks
On Monday, 17 August 2015 at 14:43:35 UTC, D_Learner wrote: Hello everyone . I need advice on my first D-project . I have uploaded it at :- Current Results for the pattern="GCAGAGAG" are as below :- BM_Runtime = 366 hnsecs position= 513 BM_Compile-time = 294 hnsecs position =513 BMH_Runtime = 174 hnsecs position= 513 BMH_Compile-time= 261 hnsecs position= 513 AG_Run-time = 258 hnsecsposition= 513 AG_Compile-time = 268 hnsecsposition= 513 Running the code : dmd -J. matcher.d inputs.d rtime_pre.d ctime_pre.d && numactl --physcpubind=0 ./matcher Hi, What happens if you run each algorithm many (say 10) times. The current times seem to short to be reliable (variation in runtimes would be too great). Regards, Edwin
A couple questions about a simple project
Hi everyone, I'm new to D (I'm learning it by reading the great online book by Ali Çehreli - thank you very much for it, sir!), and, more than that, programming is my hobby, so please bear with me if I'm asking stupid questions. I've made a toy project which is a small command-line XML files validator: https://github.com/Oire/dxv/ and I have a couple questions about it: 1. I'm using std.getopt but don't know how to make it display a help message if no options are present at all: D:\repos\git\dxv\dxv.exe (nothing happens but I would like it to show the help as with --help switch) 2. As you can see, I check whether the file to validate can be read. I tried both `try...catch` and `enforce` (current version: `string s = enforce(cast(string)std.file.read(f), "Unable to read file");` ), but this very exception for some reason can be caught only in `main()`. What am I missing? Thanks! -- With best regards from Ukraine, Andre Skype: Francophile Twitter: @m_elensule; Facebook: menelion My blog: http://menelion.oire.org/
Re: A couple questions about a simple project
On Monday, 17 August 2015 at 15:05:56 UTC, Andre Polykanine wrote:
Hi everyone,
I'm new to D (I'm learning it by reading the great online book
by Ali
Çehreli - thank you very much for it, sir!), and, more
than that,
programming is my hobby, so please bear with me if I'm asking
stupid
questions.
I've made a toy project which is a small command-line
XML files
validator:
https://github.com/Oire/dxv/
and I have a couple questions about it:
1. I'm using std.getopt but don't know how to make it display
a help
message if no options are present at all:
D:\repos\git\dxv\dxv.exe
(nothing happens but I would like it to show the help
as with
--help switch)
Check if args has changed length after calling getopt, if not
then it didn't find any options.
2. As you can see, I check whether the file to validate can be
read. I
tried both `try...catch` and `enforce` (current version:
`string s = enforce(cast(string)std.file.read(f), "Unable
to read
file");`
), but this very exception for some reason can be caught
only in
`main()`.
What am I missing?
Thanks!
string s;
try
{
s = cast(string)std.file.read(f);
}
catch (FileException e)
{
// do whatever you want.
}
Re: Compiletime Vs Runtime bencmarks
On Monday, 17 August 2015 at 14:52:18 UTC, Edwin van Leeuwen wrote: On Monday, 17 August 2015 at 14:43:35 UTC, D_Learner wrote: Hello everyone . I need advice on my first D-project . I have uploaded it at :- Current Results for the pattern="GCAGAGAG" are as below :- BM_Runtime = 366 hnsecs position= 513 BM_Compile-time = 294 hnsecs position =513 BMH_Runtime = 174 hnsecs position= 513 BMH_Compile-time= 261 hnsecs position= 513 AG_Run-time = 258 hnsecsposition= 513 AG_Compile-time = 268 hnsecsposition= 513 Running the code : dmd -J. matcher.d inputs.d rtime_pre.d ctime_pre.d && numactl --physcpubind=0 ./matcher Hi, What happens if you run each algorithm many (say 10) times. The current times seem to short to be reliable (variation in runtimes would be too great). Regards, Edwin Thyanks, I havent tried that. So it seems you suggest I must fucus on average times. Will try it , the above results are from a single run (no looping), but after executing the program several times I realised that the 1st two seem ok(relatively stable results for same pattern), but the other pair give higher performance for the run-time versions.
Re: A couple questions about a simple project
On Monday, 17 August 2015 at 15:05:56 UTC, Andre Polykanine wrote: Hi everyone, I'm new to D (I'm learning it by reading the great online book by Ali Çehreli - thank you very much for it, sir!), and, more than that, programming is my hobby, so please bear with me if I'm asking stupid questions. I've made a toy project which is a small command-line XML files validator: https://github.com/Oire/dxv/ and I have a couple questions about it: 1. I'm using std.getopt but don't know how to make it display a help message if no options are present at all: D:\repos\git\dxv\dxv.exe (nothing happens but I would like it to show the help as with --help switch) 2. As you can see, I check whether the file to validate can be read. I tried both `try...catch` and `enforce` (current version: `string s = enforce(cast(string)std.file.read(f), "Unable to read file");` ), but this very exception for some reason can be caught only in `main()`. What am I missing? Thanks! 1. getopt modifies args array leaving not processed arguments in it, i.e. name of the program and positional arguments (those without leading - or --). If there're no command line arguments given, args array will contain the only one element - the name of executable. Therefore you can check for args.length == 1 after processing by getopt. 2. catch can handle only exception of type specified in its argument and derived. std.file.read throws FileException on fail, while you catch only CheckException. To cover all cases you can catch any exception by using Exception type (it's the base class for all exception classes), or write two catch-statements in a row for both FileException and CheckException. You don't need enforce here, unless you want to check if std.file.read returns null slice.
Re: How to provide this arg or functor for algorithm?
On Monday, 17 August 2015 at 12:38:05 UTC, anonymous wrote:
auto func()(uint[] arr, uint delegate(uint) pure @nogc d) @nogc
{
return arr.map!(d);
}
void main() @nogc
{
uint[3] arr = [1,2,3];
uint context = 2;
auto c = Caller(context);
auto d = &c.method;
auto r = func(arr[], d);
import std.algorithm: equal;
import std.range: only;
assert(equal(r, only(2, 4, 6)));
}
I've just checked with my runtime GC hook. Here the call to
func() allocates 12 bytes via gc_malloc, and it's the same for a
4-elements array, so it's not for the array itself, it's for a
closure, I think.
Re: How to provide this arg or functor for algorithm?
On Monday, 17 August 2015 at 16:18:50 UTC, thedeemon wrote: I've just checked with my runtime GC hook. Here the call to func() allocates 12 bytes via gc_malloc, and it's the same for a 4-elements array, so it's not for the array itself, it's for a closure, I think. Also, compiling with -vgc says nothing, compiler (2.068) seems to miss this allocation.
Re: Weird error message.
On Sunday, 16 August 2015 at 21:32:10 UTC, Warwick wrote: Dont know what to make of this, I pretty much get it every other time I call rdmd. It'll alternate between running fine and then giving me this error... Any ideas? rdmd creates an executable and runs it immediately. If you have an antivirus, it may not complete its job in this rather short timeframe. Just run it again, AFAIK, rdmd caches the executable from the last compilation. On Monday, 17 August 2015 at 00:00:11 UTC, Jonathan M Davis wrote: Personally, I wish that Windows didn't have file locks... :( My guess, it's the executable file, which is opened by another process, if it's not completely written, running it would give even more funny results :)
Re: Weird error message.
On Monday, 17 August 2015 at 03:14:24 UTC, BBasile wrote: It's locked unless it's specified during the call to `CreateFile()` that the file can be shared for reading/writing (FILE_SHARE_READ / FILE_SHARE_WRITE). And the executable file being run must not be shared for writing, because it's mapped.
Re: A couple questions about a simple project
Hello John,
Yes, but this doesn't work, either.
Now I have this (that was my first variant, btw):
string s;
try {
s = cast(string)std.file.read(f);
try {
check(s);
if (this.verbose) {
output(format("%s:
validation passed!", f));
}
} catch(CheckException e) {
// This is output when a file is invalid, that works
output(format("Failed to
validate %s: %s", f, e.toString()));
}
} catch(Exception exc) {
// And that isn't output, I see just the stacktrace as if the
exception was not caught at all
output(format("Error reading %s: %s",
f, exc.msg));
}
}
To catch the exception, I need to wrap the validate() call in
`try...catch` in `main()`. Why so?
Thanks!
--
With best regards from Ukraine,
Andre
Skype: Francophile
Twitter: @m_elensule; Facebook: menelion
My blog: http://menelion.oire.org/
Original message
From: John Colvin via Digitalmars-d-learn
To: digitalmars-d-learn@puremagic.com
Date created: , 6:17:38 PM
Subject: A couple questions about a simple project
On Monday, 17 August 2015 at 15:05:56 UTC, Andre Polykanine wrote:
> Hi everyone,
> I'm new to D (I'm learning it by reading the great online book
> by Ali
> Çehreli - thank you very much for it, sir!), and, more
> than that,
> programming is my hobby, so please bear with me if I'm asking
> stupid
> questions.
> I've made a toy project which is a small command-line
> XML files
> validator:
> https://github.com/Oire/dxv/
> and I have a couple questions about it:
> 1. I'm using std.getopt but don't know how to make it display
> a help
> message if no options are present at all:
> D:\repos\git\dxv\dxv.exe
> (nothing happens but I would like it to show the help
> as with
> --help switch)
Check if args has changed length after calling getopt, if not
then it didn't find any options.
> 2. As you can see, I check whether the file to validate can be
> read. I
> tried both `try...catch` and `enforce` (current version:
> `string s = enforce(cast(string)std.file.read(f), "Unable
> to read
> file");`
> ), but this very exception for some reason can be caught
> only in
> `main()`.
> What am I missing?
> Thanks!
string s;
try
{
s = cast(string)std.file.read(f);
}
catch (FileException e)
{
// do whatever you want.
}
Re: A couple questions about a simple project
On 08/17/2015 10:08 AM, Andre Polykanine via Digitalmars-d-learn wrote:
> string s;
> try {
> s =
cast(string)std.file.read(f);
> try {
> check(s);
> if (this.verbose) {
>
output(format("%s: validation passed!", f));
> }
> } catch(CheckException e) {
> // This is output when a file is invalid, that works
>
output(format("Failed to validate %s: %s", f, e.toString()));
> }
> } catch(Exception exc) {
> // And that isn't output, I see just the stacktrace as if the
> exception was not caught at all
> output(format("Error reading
%s: %s", f, exc.msg));
> }
> }
Regardless of whether it is the best solution here, you can have
multiple catch blocks for a single try:
try {
// ...
} catch(CheckException e) {
// ...
} catch(Exception exc) {
// ...
}
> To catch the exception, I need to wrap the validate() call in
> `try...catch` in `main()`. Why so?
The reason is you don't try to make use of the provided file name until
validate() starts executing. If it's important that the program notify
the user right away, then you can call std.file.exists() to make sure
that the file is there. Still, it does not try to open so it can't know
whether the file will be readable later.
The funny thing is, even though the upfront check sees a file as being
present, it may disappear when it is being used or it may become unreadable.
A better solution may be to open the files first and then pass File
objects to validate().
> Thanks!
And thank you very much for the kind words! :)
Ali
Re: Compiletime Vs Runtime bencmarks
On Monday, 17 August 2015 at 14:52:18 UTC, Edwin van Leeuwen wrote: On Monday, 17 August 2015 at 14:43:35 UTC, D_Learner wrote: Hello everyone . I need advice on my first D-project . I have uploaded it at :- Current Results for the pattern="GCAGAGAG" are as below :- BM_Runtime = 366 hnsecs position= 513 BM_Compile-time = 294 hnsecs position =513 BMH_Runtime = 174 hnsecs position= 513 BMH_Compile-time= 261 hnsecs position= 513 AG_Run-time = 258 hnsecsposition= 513 AG_Compile-time = 268 hnsecsposition= 513 Running the code : dmd -J. matcher.d inputs.d rtime_pre.d ctime_pre.d && numactl --physcpubind=0 ./matcher Hi, What happens if you run each algorithm many (say 10) times. The current times seem to short to be reliable (variation in runtimes would be too great). Regards, Edwin The surprisingly, the D-profiler gives plausible results:- Algorithm1 2921 int rtime_pre.bm_rmatch (runtime ) 2122 int ctime_pre.bm_cmatch (compiletime ) 1317int rtime_pre.bmh_rmatch (runtime ) 1099int ctime_pre.bmh_cmatch (compiletime ) 3959 int rtime_pre.ag_rmatch (runtime ) 2688 pure int ctime_pre.ag_cmatch (compiletime ) This suggests that my timer design has some flaw ;)
Re: How to provide this arg or functor for algorithm?
On Monday, 17 August 2015 at 16:21:16 UTC, thedeemon wrote: On Monday, 17 August 2015 at 16:18:50 UTC, thedeemon wrote: I've just checked with my runtime GC hook. Here the call to func() allocates 12 bytes via gc_malloc, and it's the same for a 4-elements array, so it's not for the array itself, it's for a closure, I think. Also, compiling with -vgc says nothing, compiler (2.068) seems to miss this allocation. Thanks for confirming. It seems to be a known issue that the compiler doesn't recognize the @nogc violation by the closure: https://issues.dlang.org/show_bug.cgi?id=14771 That's not a regression, though. 2.067 rejecting the code has something to do with this assert: https://github.com/D-Programming-Language/phobos/blob/v2.067.1/std/algorithm/iteration.d#L453 (code is the same for 2.068). I don't know if that assert should trigger a @nogc violation or not. But anyway, the real issue is 14771, as far as I can tell.
Getting a TypeTuple of a Template's Arguments
For functions, we have std.traits.ParameterTypeTuple. Is there any equivalent functionality for templates?
Re: Compiletime Vs Runtime bencmarks
On Monday, 17 August 2015 at 17:48:22 UTC, D_Learner wrote: On Monday, 17 August 2015 at 14:52:18 UTC, Edwin van Leeuwen wrote: [...] The surprisingly, the D-profiler gives plausible results:- Algorithm1 2921 int rtime_pre.bm_rmatch (runtime ) 2122 int ctime_pre.bm_cmatch (compiletime ) 1317int rtime_pre.bmh_rmatch (runtime ) 1099int ctime_pre.bmh_cmatch (compiletime ) 3959 int rtime_pre.ag_rmatch (runtime ) 2688 pure int ctime_pre.ag_cmatch (compiletime ) This suggests that my timer design has some flaw ;) std.datetime.StopWatch is the easiest way to do timing manually, or just use std.datetime.benchmark
Re: Getting a TypeTuple of a Template's Arguments
Aside: With 2.068, std.typetuple and TypeTuple are renamed as std.meta
and AliasSeq, respectively.
On 08/17/2015 02:23 PM, Meta wrote:> For functions, we have
std.traits.ParameterTypeTuple. Is there any
> equivalent functionality for templates?
There is TemplateArgsOf for instances of templates but I don't know
anything more meta :) than that:
import std.traits;
void foo(int i, alias f, T)()
{}
void main()
{
int bar(int) { return 0; }
alias f = foo!(42, bar, int);
pragma(msg, TemplateArgsOf!(f));
}
Prints
tuple(42, bar, (int))
Ali
unusual bare metal target: Amazon Dash
I don't know whether D can run on one, but from a quick look perhaps feasible. Running D on something like this (perhaps it's underpowered, but looked to have similar spec to what people had been doing with related ARM cortex processors) would certainly make the point very vivid that it can be a bare metal programming language. Only 1Mb of flash RAM for the program - is that enough? https://learn.adafruit.com/dash-hacking-bare-metal-stm32-programming/programming https://learn.adafruit.com/dash-hacking-bare-metal-stm32-programming/overview The Amazon Dash button is a tiny device that orders products from Amazon.com at the press of a button. It's designed to be put wherever you store consumeables like paper towels, trash bags, etc. so that you can easily order more when they run out. The Dash is great at what it's designed to do, but did you know inside the Dash is a powerful ARM Cortex-M3 processor and WiFi module that are very similar to wireless development boards like the Particle Photon? You'll even find there are easily accessible test pads on the Dash which allow you to reprogram its CPU and turn it into your own $5 internet button! This guide will explore how to take apart the Dash and reprogram its CPU to run your own code. ... The CPU is a STM32F205RG6 processor which is an ARM Cortex-M3 that can run up to 120mhz and has 128 kilobytes of RAM and 1 megabyte of flash memory for program storage. The WiFi module is a BCM943362 module which in combination with the CPU make it a platform for Broadcom's WICED SDK. There's a 16 megabit SPI flash ROM which is typically used in conjunction with the WICED SDK for storing application data. An ADMP441 microphone is connected to the CPU and used by the Dash iOS application to configure the device using the speaker on a phone/tablet. There's a single RGB LED and a button.
Re: unusual bare metal target: Amazon Dash
On 18/08/2015 1:32 p.m., Laeeth Isharc wrote: I don't know whether D can run on one, but from a quick look perhaps feasible. Running D on something like this (perhaps it's underpowered, but looked to have similar spec to what people had been doing with related ARM cortex processors) would certainly make the point very vivid that it can be a bare metal programming language. Only 1Mb of flash RAM for the program - is that enough? https://learn.adafruit.com/dash-hacking-bare-metal-stm32-programming/programming https://learn.adafruit.com/dash-hacking-bare-metal-stm32-programming/overview The Amazon Dash button is a tiny device that orders products from Amazon.com at the press of a button. It's designed to be put wherever you store consumeables like paper towels, trash bags, etc. so that you can easily order more when they run out. The Dash is great at what it's designed to do, but did you know inside the Dash is a powerful ARM Cortex-M3 processor and WiFi module that are very similar to wireless development boards like the Particle Photon? You'll even find there are easily accessible test pads on the Dash which allow you to reprogram its CPU and turn it into your own $5 internet button! This guide will explore how to take apart the Dash and reprogram its CPU to run your own code. ... The CPU is a STM32F205RG6 processor which is an ARM Cortex-M3 that can run up to 120mhz and has 128 kilobytes of RAM and 1 megabyte of flash memory for program storage. The WiFi module is a BCM943362 module which in combination with the CPU make it a platform for Broadcom's WICED SDK. There's a 16 megabit SPI flash ROM which is typically used in conjunction with the WICED SDK for storing application data. An ADMP441 microphone is connected to the CPU and used by the Dash iOS application to configure the device using the speaker on a phone/tablet. There's a single RGB LED and a button. By what you are saying, I believe it should be doable. Although I'm a little worried for the WiFi support. Do you need to include the code to drive it beyond wrap up some communication to it? 1mb flash should be enough to run D code on it. If you strip out a good percentage of druntime and definitely no Phobos. Although you may be able to mark and use some of that 16mb flash rom as executable code storage. If that's so, you'll be in a good place to have more then 1mb. It would require some clever runtime linking tricks however. I'm probably not the best person to go more in depth about it or the specific chips. So I won't. Most of my knowledge comes from reading what others says and talking with Jens Bauer.
Re: Real OOP with D
On Monday, 17 August 2015 at 06:08:35 UTC, Ali Çehreli wrote:
On 08/16/2015 10:57 PM, Ozan wrote:
[...]
From the way you use it below, a better name for that class
would be FamilyMember but I get the point.
Yes, you're right.
[...]
> father.greeting;
> son.greeting;
What you mean is that the call above causes a compilation error:
Error: no property 'greeting' for type 'deneme.Family'
> }
>
[...]
My experience with OOP is limited to C++ and D. I think what
you are describing is how dynamically typed languages work. It
is impossible in compiled languages like C++ and D. When a type
is used in an expression, the compiler ensures that the call is
bound to a function.
> In D, it starts with the class definition.
Actually, 'interface' is a better fit in most cases:
interface FamilyMember
{
// ...
}
class Dad : FamilyMember
{
// ...
}
[...]
Ali
Interfaces are very helpful to avoid large inheritance trees in
OOP. On the other hand, there are not designed as workarounds
for OOP implementation problems.
The kind of OOP in D is a classical way to handle it. Dynamic
languages tries to close the gap between theoretical and
practical OOP for the price of speed.
I think that Adam's jsvar idea is a great way to bring more
flexibility into D. The same in OOP would be also great.
Regards, Ozan
Re: Real OOP with D
On Monday, 17 August 2015 at 06:10:38 UTC, Rikki Cattermole wrote:
On 17/08/2015 5:57 p.m., Ozan wrote:
Hi
[...]
import std.stdio;
abstract class Family { void greeting(); }
class Dad : Family { void greeting() { writeln("I'm dad"); } }
class Boy : Family { void greeting() { writeln("I'm daddy's
boy"); } }
void main() {
Family dad = new Dad;
Family boy = new Boy;
dad.greeting;
boy.greeting;
}
I'm confused how this isn't real OOP?
Replace 'real' with 'theoretical' OOP. Every instance of a class
(object) is like an independent black box. Every public message
(method / function) of the class definition could be called when
ever you want. Variables are like pointers to objects. With
inheritance and overriding you're losing in class type
implementations of OOP a lot of 'theoretical' flexibility. I was
asking for a possibility to avoid this.
Regards Ozan
Re: Real OOP with D
On Monday, 17 August 2015 at 06:59:51 UTC, BBasile wrote: On Monday, 17 August 2015 at 05:57:52 UTC, Ozan wrote: Hi [...] Is there any way to get real OOP with D? Regards, Ozan Can you name an OOP oriented language that allows this ? Your example is eroneous OOP. The 2 other answers you 've got (the first using an interface and the second using an abstract class) are valid OOP. One of the fundamental concept OOP is that a function defined in a class exists also in its subclasses. So how do you expect `greeting()` to exist in Family if it's only defined in its sub-classes ? You can verify that with the 'Liskov substitution principle' (https://en.wikipedia.org/wiki/Liskov_substitution_principle). Actually your sample violates this principle. Languages like Groovy or JavaScript (with the help of frameworks ;-) And I believe many more the newer ones. But that's not the point. And... This was not a criticism against D (... "bad D, has no understanding of OOP. Boahh" ;-) It was only a question about handling of a typical OOP problem in a class-typed implementation of OOP like D has. Thanks to every existing or new creative programming language, today we have so many other ways to solve our programming problems. Regards Ozan
