std.algorithm range violation

2014-05-28 Thread maarten van damme via Digitalmars-d-learn
an anyone explain me what I'm doing wrong here :

[code]
dstring[][dstring] providor_symbol_map;
...

writeln(providor_symbol_map.keys.sort!((x,y)=providor_symbol_map[x].length=providor_symbol_map[y].length));
[/code]

output:
core.exception.RangeError@std.algorithm(9429): Range violation


Re: std.algorithm range violation

2014-05-28 Thread Wanderer via Digitalmars-d-learn

On Wednesday, 28 May 2014 at 10:10:41 UTC, maarten van damme via
Digitalmars-d-learn wrote:

an anyone explain me what I'm doing wrong here :

[code]
dstring[][dstring] providor_symbol_map;
...

writeln(providor_symbol_map.keys.sort!((x,y)=providor_symbol_map[x].length=providor_symbol_map[y].length));
[/code]

output:
core.exception.RangeError@std.algorithm(9429): Range violation


dstring[][dstring] declaration looks a bit obscure to me...
what do you intent with it, array of maps or map of arrays?

Also, it looks unnatural that inside sorting lambda, you refer
outside from it (back to providor_symbol_map variable). Ideally,
you should only use variables x and y. Does D support sorting by
map entries instead of by keys only or by values only?


Re: std.algorithm range violation

2014-05-28 Thread maarten van damme via Digitalmars-d-learn
I'm trying to analyze the usage of certain words in a large number of spam
emails, and I want for every interesting word a list of 'providors', that
mentioned that word. with associative arrays I hoped to get it by using
array[interestingworde].

And I have to refer outside from sort(x,y) as associative arrays have no
order, I'll always have to sort a key-array according to values obtained
through the associative array.
It's supposed to be a delegate anyway, otherwise the least it could do is
throw a compilation error.


2014-05-28 12:53 GMT+02:00 Wanderer via Digitalmars-d-learn 
digitalmars-d-learn@puremagic.com:

 On Wednesday, 28 May 2014 at 10:10:41 UTC, maarten van damme via

 Digitalmars-d-learn wrote:

 an anyone explain me what I'm doing wrong here :

 [code]
 dstring[][dstring] providor_symbol_map;
 ...

 writeln(providor_symbol_map.keys.sort!((x,y)=providor_
 symbol_map[x].length=providor_symbol_map[y].length));
 [/code]

 output:
 core.exception.RangeError@std.algorithm(9429): Range violation


 dstring[][dstring] declaration looks a bit obscure to me...
 what do you intent with it, array of maps or map of arrays?

 Also, it looks unnatural that inside sorting lambda, you refer
 outside from it (back to providor_symbol_map variable). Ideally,
 you should only use variables x and y. Does D support sorting by
 map entries instead of by keys only or by values only?



Re: std.algorithm range violation

2014-05-28 Thread bearophile via Digitalmars-d-learn

maarten van damme:


writeln(providor_symbol_map.keys.sort!((x,y)=providor_symbol_map[x].length=providor_symbol_map[y].length));
[/code]


Try:

((x, y) = providor_symbol_map[x].length  
providor_symbol_map[y].length)


Bye,
bearophile


Re: std.algorithm range violation

2014-05-28 Thread Wanderer via Digitalmars-d-learn

Sorry about typo, I meant

providor_symbol_map.sort!((x,y)={x.value.lengthy.value.length})

above.


Re: std.algorithm range violation

2014-05-28 Thread Wanderer via Digitalmars-d-learn
Aha, so you want to maintain spam word - set of senders 
relationship, so it's actually map of sets and your declaration 
is correct. You only need to sort map's entries (key and value 
pairs together).


If D supports that, it should be something like 
providor_symbol_map.sort!((x,y)={x.value.length=y.value.length}), 
but I'm not sure it would work...


But I'm just learning D (and very much like it so far!), 
hopefully someone more skilled will reply as well. :-)


Re: std.algorithm range violation

2014-05-28 Thread bearophile via Digitalmars-d-learn

Wanderer:


providor_symbol_map.sort!((x,y)={x.value.length=y.value.length}),


This lambda doesn't return a boolean. Also, add spaces around 
operators and after commas.


Bye,
bearophile


Re: std.algorithm range violation

2014-05-28 Thread maarten van damme via Digitalmars-d-learn
wow.
senpai, teach me what I did wrong...


2014-05-28 13:21 GMT+02:00 bearophile via Digitalmars-d-learn 
digitalmars-d-learn@puremagic.com:

 maarten van damme:


  writeln(providor_symbol_map.keys.sort!((x,y)=providor_
 symbol_map[x].length=providor_symbol_map[y].length));
 [/code]


 Try:

 ((x, y) = providor_symbol_map[x].length  providor_symbol_map[y].length)

 Bye,
 bearophile



Cost of .dup vs. instantiation

2014-05-28 Thread Chris via Digitalmars-d-learn
I use Appender to fill an array. The Appender is a class variable 
and is not instantiated with each function call to save 
instantiation. However, the return value or the function must be 
dup'ed, like so:


Appender!(MyType[]) append;
public auto doSomething() {
  scope (exit) { // clear append }
  // ... do something
  append ~= item;
  return (append.data).dup
}

My question is whether I save anything with Appender as a class 
variable here. I have to .dup the return value (+ clear the 
Appender). If I had a new Appender with each function call, it 
might be just as good.


public auto doSomething() {
  Appender!(MyType[]) append;
  // 
  return append.data.
}

Right or wrong?



Re: Cost of .dup vs. instantiation

2014-05-28 Thread monarch_dodra via Digitalmars-d-learn

On Wednesday, 28 May 2014 at 14:36:25 UTC, Chris wrote:
I use Appender to fill an array. The Appender is a class 
variable and is not instantiated with each function call to 
save instantiation. However, the return value or the function 
must be dup'ed, like so:


Appender!(MyType[]) append;
public auto doSomething() {
  scope (exit) { // clear append }
  // ... do something
  append ~= item;
  return (append.data).dup
}

My question is whether I save anything with Appender as a class 
variable here. I have to .dup the return value (+ clear the 
Appender). If I had a new Appender with each function call, it 
might be just as good.


public auto doSomething() {
  Appender!(MyType[]) append;
  // 
  return append.data.
}

Right or wrong?


You might save a little because you avoid the cost of growing 
your appender repeatedly: Once the appender has come to 
maturity, it will very likely stop growing.


At that point, you only pay for *1* allocation per call to 
doSomething. Further advantages include:

 - dup has APPENDABLE info (whereas appender.data does not).
 - less wasted memory: dup uses no more memory than it has to, 
whereas Appender may over-allocate, depending on how you fill it.


The downside to your approach is that you keep a handle on a 
buffer that can grow, but never shrink. If a at a certain point, 
you have to process some particularly large input, then you'll 
consume excessive amounts of memory.


Re: std.algorithm range violation

2014-05-28 Thread monarch_dodra via Digitalmars-d-learn

On Wednesday, 28 May 2014 at 11:40:05 UTC, Wanderer wrote:

Sorry about typo, I meant

providor_symbol_map.sort!((x,y)={x.value.lengthy.value.length})

above.


providor_symbol_map is an Associative Array, so you can't sort 
that. *Usually*, you want to do what the OP did, which is to get 
the keys, and sort them, but leave the AA unchanged. EG:


Val[Key] myAA;
Key[] mySortedKeys = myAA.keys.sort!((x, y)= compare(myAA[x], 
myAA[y]))()


//Print values in incremented order:
foreach(key; mySortedKeys)
writefln(%s: %s, key, myAA[key]);


Re: Programming a Game in D? :D

2014-05-28 Thread David via Digitalmars-d-learn

On Tuesday, 27 May 2014 at 10:13:13 UTC, Szymon Gatner wrote:

On Tuesday, 27 May 2014 at 10:03:36 UTC, David wrote:

On Saturday, 24 May 2014 at 08:54:53 UTC, ponce wrote:


Hi David,

Learning programming, learning D and learning 3D are 3 
significant endeavours.
You might want to begin with http://www.basic4gl.net/ which 
will get you going with 3D, quite a topic in itself.

Then learn D regardless :)


So, I'v used Blender for a half year or sth. and I think I can 
make a little area :)
As far as I know, I do now need a graphic and physics engines, 
1 of the graphic APIs and for sure my programming stuff and 
here I'm stuck :D


And I still can't install Mono-D :( if I try I just get a 
whole bunch of errors that any packages couldn't be found, 
don't know if I'm doing sth. wrong

(I probably do :P)


I would STRONGLY advise to go with a ready engine like Unity.

You still have to learn a lot before you  will have just 
building blocks to create a game like loading and rendering 3D 
models, a gameplay framework etc etc.


Start with Unity, lean how to make a game there. Learn how to 
programm gameplay there and after that, when you see what is 
needed before even being able to make a game, only then try to 
make things from scratch. Use C# in Unity too as it is similar 
to D so you will have easier transition when necessary.


Ok, now I just wonder wich Engine. (I know everybody hates the
discussion about the best engine.) CryEngine, UDK, Unity or a
less known Engine?


Re: Cost of .dup vs. instantiation

2014-05-28 Thread TheFlyingFiddle via Digitalmars-d-learn

On Wednesday, 28 May 2014 at 14:36:25 UTC, Chris wrote:
I use Appender to fill an array. The Appender is a class 
variable and is not instantiated with each function call to 
save instantiation. However, the return value or the function 
must be dup'ed, like so:


Appender!(MyType[]) append;
public auto doSomething() {
  scope (exit) { // clear append }
  // ... do something
  append ~= item;
  return (append.data).dup
}

My question is whether I save anything with Appender as a class 
variable here. I have to .dup the return value (+ clear the 
Appender). If I had a new Appender with each function call, it 
might be just as good.


public auto doSomething() {
  Appender!(MyType[]) append;
  // 
  return append.data.
}

Right or wrong?


When it comes to optimizations it's hard to say. Benchmarking is 
better than relying advice/opinions on the internet in any case.


That being said i doubt that the instantiation cost of the 
Appender is relevant. (Btw the appender is not a class variable! 
It is a struct with reference semantics). Reusing an appender is 
more for those cases where you want to reuse the underlying 
memory of the appender itself.




Re: std.algorithm range violation

2014-05-28 Thread monarch_dodra via Digitalmars-d-learn

On Wednesday, 28 May 2014 at 17:39:15 UTC, monarch_dodra wrote:

On Wednesday, 28 May 2014 at 11:40:05 UTC, Wanderer wrote:

Sorry about typo, I meant

providor_symbol_map.sort!((x,y)={x.value.lengthy.value.length})

above.


providor_symbol_map is an Associative Array, so you can't sort 
that. *Usually*, you want to do what the OP did, which is to 
get the keys, and sort them, but leave the AA unchanged. EG:


Val[Key] myAA;
Key[] mySortedKeys = myAA.keys.sort!((x, y)= compare(myAA[x], 
myAA[y]))()


//Print values in incremented order:
foreach(key; mySortedKeys)
writefln(%s: %s, key, myAA[key]);


I case this was not clear compare is an function you should 
replace with your own. It should simply define strict ordering of 
x and y.  is one such function.


Re: Programming a Game in D? :D

2014-05-28 Thread Ryan Voots via Digitalmars-d-learn

On Wednesday, 28 May 2014 at 17:46:23 UTC, David wrote:


Ok, now I just wonder wich Engine. (I know everybody hates the
discussion about the best engine.) CryEngine, UDK, Unity or a
less known Engine?


The best engine is the one you can get work done with.  Unity 
seems to have a pretty good community around it lately and has a 
free version to play with.  Having all of that documentation and 
community to fall back on is likely to be a benefit if you aren't 
hugely experienced yet.


@safe @nogc memory allocation

2014-05-28 Thread Nordlöw

I would like my radix sort function radixSortImpl() at

https://github.com/nordlow/justd/blob/master/intsort.d

to not use the GC. However, when I tag with @nogc I get the error:

intsort.d(195,47): Error: @nogc function 
'isort.radixSortImpl!(byte[], a, false).radixSortImpl' cannot 
call non-@nogc function 'std.array.uninitializedArray!(byte[], 
immutable(ulong)).uninitializedArray'


Is there an alternative to

std.array: uninitializedArray
Elem[] y = uninitializedArray!(Elem[])(n);

that neither use the GC and nor preinitialize the data?

Could the recent DMD pull optimization to scope here

https://github.com/D-Programming-Language/dmd/commit/abc7033bf9cf7f7224a47e45096efc48a21b5ab8

be used?

/Per


Re: @safe @nogc memory allocation

2014-05-28 Thread monarch_dodra via Digitalmars-d-learn

On Wednesday, 28 May 2014 at 19:43:53 UTC, Nordlöw wrote:

I would like my radix sort function radixSortImpl() at

https://github.com/nordlow/justd/blob/master/intsort.d

to not use the GC. However, when I tag with @nogc I get the 
error:


intsort.d(195,47): Error: @nogc function 
'isort.radixSortImpl!(byte[], a, false).radixSortImpl' cannot 
call non-@nogc function 'std.array.uninitializedArray!(byte[], 
immutable(ulong)).uninitializedArray'


Is there an alternative to

std.array: uninitializedArray
Elem[] y = uninitializedArray!(Elem[])(n);

that neither use the GC and nor preinitialize the data?


malloc? There's no wrapper around it though, like there is for 
uninitializedArray.


Keep in mind though that currently, you have to choose either of 
pure (GC) or nogc (malloc) if you need dynamic allocation :/



Could the recent DMD pull optimization to scope here

https://github.com/D-Programming-Language/dmd/commit/abc7033bf9cf7f7224a47e45096efc48a21b5ab8

be used?

/Per


I don't think scope can be used to create a dynamic array on the 
stack. I think it requires the object's type be statically known. 
I could be wrong though.


If you know n has a max size, you could you create a fixed size 
array, or attempt a alloca array?


Re: @safe @nogc memory allocation

2014-05-28 Thread safety0ff via Digitalmars-d-learn
I think malloc isn't @safe and alloca doesn't work if your 
function can throw.


Re: @safe @nogc memory allocation

2014-05-28 Thread monarch_dodra via Digitalmars-d-learn

On Wednesday, 28 May 2014 at 20:00:17 UTC, safety0ff wrote:
I think malloc isn't @safe and alloca doesn't work if your 
function can throw.


Yeah, uninitializedArray is also *only* trusted if the type in 
question has no indirections.


I've heard of several bugs with alloca, but I don't know the 
exact list.


Looping over all enum values

2014-05-28 Thread Mark Isaacson via Digitalmars-d-learn

Is there a mechanism that allows you to loop over all of an
enum's values? I've wanted to do so a couple times now for
CTFE/mixin templates.

I was able to loop over the underlying type when my enum was
integer-based, but I can't do that if the values are strings
(also that solution is quite hacky).

Perhaps there's a pattern involving __traits?


Re: Looping over all enum values

2014-05-28 Thread Adam D. Ruppe via Digitalmars-d-learn

On Wednesday, 28 May 2014 at 20:19:45 UTC, Mark Isaacson wrote:

Is there a mechanism that allows you to loop over all of an
enum's values? I've wanted to do so a couple times now for
CTFE/mixin templates.


__traits(allMembers) on the enum can do it or this can help too 
http://dlang.org/phobos/std_traits.html#EnumMembers


Re: Looping over all enum values

2014-05-28 Thread Mark Isaacson via Digitalmars-d-learn

On Wednesday, 28 May 2014 at 20:20:37 UTC, Adam D. Ruppe wrote:

On Wednesday, 28 May 2014 at 20:19:45 UTC, Mark Isaacson wrote:

Is there a mechanism that allows you to loop over all of an
enum's values? I've wanted to do so a couple times now for
CTFE/mixin templates.


__traits(allMembers) on the enum can do it or this can help too 
http://dlang.org/phobos/std_traits.html#EnumMembers


Brilliant! Thanks Adam! I actually checked your book before any
other sources for this :)


Re: @safe @nogc memory allocation

2014-05-28 Thread Nordlöw
malloc? There's no wrapper around it though, like there is for 
uninitializedArray.


Is the fact that

malloc() can't be pure when new is

a limitiation in the type system?

Do we need a yet another code tag for this?

/Per


Re: @safe @nogc memory allocation

2014-05-28 Thread Dicebot via Digitalmars-d-learn

On Wednesday, 28 May 2014 at 20:51:08 UTC, Nordlöw wrote:
malloc? There's no wrapper around it though, like there is for 
uninitializedArray.


Is the fact that

malloc() can't be pure when new is

a limitiation in the type system?

Do we need a yet another code tag for this?

/Per


It is also because `malloc` can return null when out of memory 
and `new` will throw an Error. Wrapper around `malloc` that 
throws `OutOfMemoryError` on null can be considered of same 
purity class as `new`.


Re: @safe @nogc memory allocation

2014-05-28 Thread bearophile via Digitalmars-d-learn

Dicebot:

It is also because `malloc` can return null when out of memory 
and `new` will throw an Error. Wrapper around `malloc` that 
throws `OutOfMemoryError` on null can be considered of same 
purity class as `new`.


One wrapper should have a template argument to specify the type 
of the items, to avoid the need of a cast. And instead of 
throwing an error it could also return a Nullable (the sizeof of 
such Nullable is the same as a pointer).


Nullable!(Titem*, null) talloc(Titem)(in size_t nItems);

Bye,
bearophile


Re: @safe @nogc memory allocation

2014-05-28 Thread Dicebot via Digitalmars-d-learn

On Wednesday, 28 May 2014 at 21:09:26 UTC, bearophile wrote:

Dicebot:

It is also because `malloc` can return null when out of memory 
and `new` will throw an Error. Wrapper around `malloc` that 
throws `OutOfMemoryError` on null can be considered of same 
purity class as `new`.


One wrapper should have a template argument to specify the type 
of the items, to avoid the need of a cast. And instead of 
throwing an error it could also return a Nullable (the sizeof 
of such Nullable is the same as a pointer).


Nullable!(Titem*, null) talloc(Titem)(in size_t nItems);

Bye,
bearophile


I don't think wrapper with Nullable can be pure as it will 
possibly return two different object values (and not just 
different pointers) when called with same argument list. Throwing 
an Error is crucial here.


Re: @safe @nogc memory allocation

2014-05-28 Thread Nordlöw
It is also because `malloc` can return null when out of memory 
and `new` will throw an Error. Wrapper around `malloc` that 
throws `OutOfMemoryError` on null can be considered of same 
purity class as `new`.


Does this mean that I should write and use such a wrapper for 
malloc?


/Per


Re: Programming a Game in D? :D

2014-05-28 Thread Francesco Cattoglio via Digitalmars-d-learn

On Wednesday, 28 May 2014 at 17:46:23 UTC, David wrote:

Ok, now I just wonder wich Engine. (I know everybody hates the
discussion about the best engine.) CryEngine, UDK, Unity or a
less known Engine?


I'll be honest, perhaps I risk being misunderstood, but the 
questions you are asking denote a lack of even basic knowledge 
about the subject, so I really think you should do some good 
amount of research before even trying to write something on your 
own.


Have you tried at least some free tools that allow you to script 
stuff and have simple stuff displayed on screen? I'm talking 
about stuff like Construct 2, GameMaker, RPGMaker, zGameEditor... 
even map editors like the ones from Blizzard (WarCraft 3 : TFT or 
StarCraft 2)?


Re: Programming a Game in D? :D

2014-05-28 Thread David via Digitalmars-d-learn
On Wednesday, 28 May 2014 at 21:38:07 UTC, Francesco Cattoglio 
wrote:


I'll be honest, perhaps I risk being misunderstood, but the 
questions you are asking denote a lack of even basic knowledge 
about the subject, so I really think you should do some good 
amount of research before even trying to write something on 
your own.




Well, I really don't have a lot of knowledge but I don't know 
where to start.
The Problem is just that there is sooo much stuff in the internet 
and it's kinda hard to get some knowledge.


Have you tried at least some free tools that allow you to 
script stuff and have simple stuff displayed on screen? I'm 
talking about stuff like Construct 2, GameMaker, RPGMaker, 
zGameEditor... even map editors like the ones from Blizzard 
(WarCraft 3 : TFT or StarCraft 2)?


So, i made a very little game with delphi Genesis3D and an Editor 
i don't remember about 2 years ago, but i don't know if i really 
knew what i was doing there :P


Re: @safe @nogc memory allocation

2014-05-28 Thread Dicebot via Digitalmars-d-learn

On Wednesday, 28 May 2014 at 21:31:41 UTC, Nordlöw wrote:
It is also because `malloc` can return null when out of memory 
and `new` will throw an Error. Wrapper around `malloc` that 
throws `OutOfMemoryError` on null can be considered of same 
purity class as `new`.


Does this mean that I should write and use such a wrapper for 
malloc?


/Per


I don't know. I believe within current language semantics even 
considering `new` pure is broken, there was a very recent thread 
discussing it in digitalmars.D group.


If you can be sure that your code won't break basic sanity 
requirements (never comparing allocated immutable pointer 
identity, only pointed values) it should work fine. But I have 
never done it in my code and not aware of possible pitfalls.


Re: @safe @nogc memory allocation

2014-05-28 Thread safety0ff via Digitalmars-d-learn

On Wednesday, 28 May 2014 at 23:57:40 UTC, Dicebot wrote:


I believe within current language semantics even considering 
`new` pure is broken, there was a very recent thread discussing 
it in digitalmars.D group.


If you can be sure that your code won't break basic sanity 
requirements (never comparing allocated immutable pointer 
identity, only pointed values) it should work fine. But I have 
never done it in my code and not aware of possible pitfalls.


You also have to make sure your calls to malloc wont be 
considered strongly pure and memoized.

e.g.:
int* a = cast(int*)malloc(4); // 4 should be considered immutable
int* b = cast(int*)malloc(4);

// a == b if memoized
// a != b otherwise (unless out of memory)

Perhaps the wrapper function should take a pointer reference as a 
parameter (note: not immutable,) this also means that it can use 
type inference.