Re: Threading Questions

[Kagamin via Digitalmars-d-learn]

On Friday, 25 September 2015 at 15:19:27 UTC, bitwise wrote:
I know that all global variables are TLS unless explicitly 
marked as 'shared', but someone once told me something about 
'shared' affecting member variables in that accessing them from 
a separate thread would return T.init instead of the actual 
value... or something like that. This seems to be 
wrong(thankfully).


T.init is returned for TLS variable when accessed from a thread 
for which it wasn't initialized.

Re: Mac IDE with Intellisense

[Marco Leise via Digitalmars-d-learn]

Am Sat, 26 Sep 2015 10:38:25 +
schrieb Gary Willoughby :

> Auto-complete in D is tricky because of this feature and no-one 
> has invested any time to figure out a nice way to provide 
> auto-complete for this.

Mono-D does have UFCS auto-complete. The plugin is going to
bit-rot though, since its only developer is done studying.

-- 
Marco

Re: WTF does "Enforcement failed" actually mean?

[Marco Leise via Digitalmars-d-learn]

Am Thu, 01 Oct 2015 08:52:43 +
schrieb John Colvin :

> On Thursday, 1 October 2015 at 07:08:00 UTC, Russel Winder wrote:
> > On Wed, 2015-09-30 at 23:35 -0700, Ali Çehreli via 
> > Digitalmars-d-learn wrote:
> >> On 09/30/2015 10:46 PM, Russel Winder via Digitalmars-d-learn 
> >> wrote:
> >> > [...]
> >> 
> >> It's coming from the following no-message enforce():
> >> 
> >>  enforce(!r.empty);
> >> 
> >> 
> >> https://github.com/D-Programming-Language/phobos/blob/master/std/algo
> >> rithm/iteration.d#L2481
> >> 
> >> You are using the no-seed version of reduce(), which uses the 
> >> first element as seed, which means that the range cannot be 
> >> empty.
> >
> > Well that explanation (*) makes it abundantly clear that the 
> > error reporting from this part of Phobos is distinctly 
> > substandard, let alone below par.
> >
> >
> > (*) Which is clear and informative!
> 
> Bug report? Then it'll get fixed.

The problem is that in out minds addition has an implicit seed
value of 0 and multiplication has 1, so a potentially empty
range doesn't immediately raise a red flag.

The correct thing to use, following this train of thought, is
http://dlang.org/phobos/std_algorithm_iteration.html#.sum
(Additionally it provides better accuracy when summing up
floating-point values.)

-- 
Marco

Re: Which GDC to download?

[Adam D. Ruppe via Digitalmars-d-learn]

On Thursday, 1 October 2015 at 12:04:40 UTC, NX wrote:
1) Why there is a download targeting arm-linux-gnueabi(hf) and 
what exactly it means? Is this a cross-compiler which will 
produce obj files containing ARM instructions or what? If so, 
will linking just work? and how?


Yes, that's a cross compiler. You run it on Windows to produce 
programs for an ARM device running Linux (for example, you do 
your development on Windows but want the program to run on a 
Raspberry Pi)


3) Which one to choose if I just want to write & compile 
windows programs?


The x86_64-w64-mingw32 one. That means Intel processor, Windows 
64 bit. mingw32 is the library used by gcc to make Windows 
programs.


You could also use the 32 bit one below, i686-w64-mingw32, both 
should work on Windows.


4) x86_64-w64-mingw32 is commented as "Unsupported alpha build. 
SEH"? is that means windows-targeting version of the compiler 
is highly unstable/not ready yet? What's "SEH"?


SEH is Windows' "Structured Exception Handling". The open source 
compilers (not just D, basically all of them) historically 
haven't done a great job implementing that but have recently been 
fixing their problems.


You'll probably be fine using it though.

Re: Interval Arithmetic

[Marco Leise via Digitalmars-d-learn]

Am Tue, 29 Sep 2015 21:04:00 +
schrieb Wulfrick :

> Is there an interval arithmetic library in D? I couldn’t find one.
> 
> In case I had to write my own, I understand that the IEEE 
> standard floating point arithmetic provides operations for 
> rounding up or down certain operations like summing, subtracting, 
> etc. (thus overriding the default behavior of rounding to nearest 
> representable).
> 
> How do I access this functionality in D? At first I thought that 
> std.math.nextDown and nextUp is what I needed, but not so. 
> Apparently these functions return the previous or next 
> representable *after* the calculation has been done.
> 
> For example, I would like the value of x+y rounded in the 
> arithmetic towards -\infty, which may or may not be nextDown(x+y).
> 
> Any luck?
> Thanks for reading!

Yes, Phobos provides you with this thing:
http://dlang.org/phobos/std_math.html#.FloatingPointControl
Read the help carefully. End of the scope generally means "}".

You can also use the C standard library from D and use:
http://www.cplusplus.com/reference/cfenv/fesetround/

  import core.stdc.fenv;
  fesetround( FE_DOWNWARD );
  auto z = x + y;

And if all that still isn't enough you can write it in inline
assembler using the `fldcw` mnemonic.

Note that the FP control word is per thread and any external
code you call or even buggy interrupt handlers could change or
reset it to defaults. Known cases include a faulty printer
driver and Delphi's runtime, which enables FP exceptions to
throw exceptions on division by 0. Just saying this so if it
ever happens you have it in the back of your mind. Against
interrupt handlers you probably cannot protect, but when
calling other people's code it would be best not depend on
what the FP control word is set to on return.
`FloatingPointControl` is nice here, because you can
temporarily set the rounding mode directly for a block of FP
instructions where no external libraries are involved.

-- 
Marco

Which GDC to download?

[NX via Digitalmars-d-learn]

Windows X86 64bit (x86_64-w64-mingw32)

Standard builds
Target  DMDFE   Runtime GCC GDC revisionBuild 
Date
arm-linux-gnueabi   2.066.1 yes 5.2.0   dadb5a3784  
2015-08-30
arm-linux-gnueabihf 2.066.1 yes 5.2.0   dadb5a3784  
2015-08-30
x86_64-w64-mingw32  2.066.1 yes 5.2.0   dadb5a3784  
2015-08-30

I'm totally confused about what does these mean:

1) Why there is a download targeting arm-linux-gnueabi(hf) and 
what exactly it means? Is this a cross-compiler which will 
produce obj files containing ARM instructions or what? If so, 
will linking just work? and how?


2) Is what I understand from "cross-compiler" correct? (a 
compiler that can target different architectures than the host 
architecture it's compiled for)


3) Which one to choose if I just want to write & compile windows 
programs?


4) x86_64-w64-mingw32 is commented as "Unsupported alpha build. 
SEH"? is that means windows-targeting version of the compiler is 
highly unstable/not ready yet? What's "SEH"?

Re: Interval Arithmetic

[ponce via Digitalmars-d-learn]

On Thursday, 1 October 2015 at 11:40:28 UTC, Marco Leise wrote:


Note that the FP control word is per thread and any external 
code you call or even buggy interrupt handlers could change or 
reset it to defaults. Known cases include a faulty printer 
driver and Delphi's runtime, which enables FP exceptions to 
throw exceptions on division by 0. Just saying this so if it 
ever happens you have it in the back of your mind. Against 
interrupt handlers you probably cannot protect, but when 
calling other people's code it would be best not depend on what 
the FP control word is set to on return. `FloatingPointControl` 
is nice here, because you can temporarily set the rounding mode 
directly for a block of FP instructions where no external 
libraries are involved.


I have a RAII struct to save/restore the FP control word.
It also handle the SSE control word which unfortunately exist.

https://github.com/p0nce/dplug/blob/master/plugin/dplug/plugin/fpcontrol.d

Re: Which GDC to download?

[Johannes Pfau via Digitalmars-d-learn]

Am Thu, 01 Oct 2015 12:04:38 +
schrieb NX :

> Windows X86 64bit (x86_64-w64-mingw32)
> 
> Standard builds
> TargetDMDFE   Runtime
> GCC   GDC revisionBuild Date arm-linux-gnueabi
> 2.066.1   yes 5.2.0   dadb5a3784
> 2015-08-30 arm-linux-gnueabihf2.066.1 yes
> 5.2.0 dadb5a3784  2015-08-30
> x86_64-w64-mingw322.066.1 yes
> 5.2.0 dadb5a3784  2015-08-30
> 
> I'm totally confused about what does these mean:
> 
> 1) Why there is a download targeting arm-linux-gnueabi(hf) and 
> what exactly it means? Is this a cross-compiler which will 
> produce obj files containing ARM instructions or what? If so, 
> will linking just work? and how?

Linking only works for libraries which are included with the cross
compiler. That usually means only the C/C++/D standard libraries will
be available. You can link to other libraries with a cross-compiler, but
you need to provides these libraries in some way:

http://wiki.dlang.org/GDC/Cross_Compiler
http://wiki.dlang.org/GDC/Cross_Compiler/Existing_Sysroot
http://wiki.dlang.org/GDC/Cross_Compiler/Existing_Sysroot#Using_a_compiler_from_gdcproject.org.2Fdownloads

For more information:
http://build-gdc.readthedocs.org/en/latest/Cross-Compiler%20Basics/

> 
> 2) Is what I understand from "cross-compiler" correct? (a 
> compiler that can target different architectures than the host 
> architecture it's compiled for)
> 
> 3) Which one to choose if I just want to write & compile windows 
> programs?
> 

Adding to Adams answer I guess we (the GDC team) have to somehow
present 'native compilers' more prominently.

> 4) x86_64-w64-mingw32 is commented as "Unsupported alpha build. 
> SEH"? is that means windows-targeting version of the compiler is 
> highly unstable/not ready yet? What's "SEH"?

Unfortunately Windows GDC builds are very unstable right now. I'd
recommend using DMD or LDC for Windows.

Re: Regex start/end position of match?

[Adam D. Ruppe via Digitalmars-d-learn]

On Thursday, 1 October 2015 at 03:29:29 UTC, Gerald wrote:

I'm stuck though on how to get the start/end index of a match?


I couldn't find one either so I did the pre/post/hit things 
broken up.


Take a look at this little program I wrote:

http://arsdnet.net/dcode/replacer/

All the files it needs are there, so you can browse by http or 
download them somewhere and compile+run to give it a try.


Lines 73-78 show the pre/hit/post thing, with me changing the 
colors of the output so they match.


Afterward, I replace one instance and draw it again to show what 
the new line would look like. (The point of my program is to 
interactively request confirmation of every individual change you 
are going to make.)



Something similar will probably work for you too.

Re: How to use std.experimental.logger?

[Panke via Digitalmars-d-learn]

Ah, I tried to format a custom struct that has a non-pure 
toString, because std.conv.to isn't pure either, sigh :(

Re: Which GDC to download?

[NX via Digitalmars-d-learn]

Thanks both to you for answers...

On Thursday, 1 October 2015 at 14:07:02 UTC, Johannes Pfau wrote:
Unfortunately Windows GDC builds are very unstable right now. 
I'd recommend using DMD or LDC for Windows.


Well... To me it's surprising GDC is not usable on windows but I 
doubt LDC is more stable.  Sad...


*Cries in Turkish*

Re: Regex start/end position of match?

[Gerald via Digitalmars-d-learn]

Thanks Adam, that was the hint I needed. For a given RegexMatch 
the pre().length() is essentially equivalent to the start 
position and taking pre().length + hit.length() gives the end 
position so I think this should be OK for my needs.

Re: an example of parallel calculation of metrics

[Jay Norwood via Digitalmars-d-learn]

On Thursday, 1 October 2015 at 07:03:40 UTC, Ali Çehreli wrote:

Looks like a bug. Workaround: Get rid of member names


Thanks.  My particular use case, working with metric expressions, 
is easier to understand if I use the names.  I converted the use 
of Tuple to struct to see if I could get an easier error msg. 
Turns out the use of struct also results in much cleaner writeln 
text.


Still has the compile error, though.

import std.algorithm, std.parallelism, std.range;
import std.stdio;
import std.datetime;
import std.typecons;
import std.meta;

// define some input measurement sample tuples and output metric 
tuples

struct TR {double per_sec; double per_cycle; long raw;}
struct TI {long proc_cyc;  long DATA_RD; long DATA_WR; long 
INST_FETCH; long L1I_MISS; long L1I_HIT; long L1D_HIT; long 
L1D_MISS;}

struct TO { TR L1_MISS; TR L1_HIT; TR DATA_ACC; TR ALL_ACC;}
const double CYC_PER_SEC = 1_600_000_000;

// various metric definitions
// using Tuples with defined names for each member, and use the 
names here in the metrics.
TR met_l1_miss ( ref TI m){ TR rv; with(rv) with(m) { raw = 
L1I_MISS+L1D_MISS; per_cycle = cast(double)raw/proc_cyc; per_sec 
= per_cycle*CYC_PER_SEC;} return rv; }
TR met_l1_hit ( ref TI m){ TR rv; with(rv) with(m) { raw = 
L1I_HIT+L1D_HIT; per_cycle = cast(double)raw/proc_cyc; per_sec = 
per_cycle*CYC_PER_SEC;} return rv; }
TR met_data_acc ( ref TI m){ TR rv; with(rv) with(m) { raw = 
DATA_RD+DATA_WR; per_cycle = cast(double)raw/proc_cyc; per_sec = 
per_cycle*CYC_PER_SEC;} return rv; }
TR met_all_acc( ref TI m){ TR rv; with(rv) with(m) { raw = 
DATA_RD+DATA_WR+INST_FETCH; per_cycle = cast(double)raw/proc_cyc; 
per_sec = per_cycle*CYC_PER_SEC;} return rv; }


// a convenience to use all the metrics above as a list
alias Metrics = 
AliasSeq!(met_l1_miss,met_l1_hit,met_data_acc,met_all_acc);


void main(string[] argv)
{
auto samples = iota(1_00);
auto meas = new TI[samples.length];
auto results = new TO[samples.length];

// Initialize some values for the measured samples
foreach(i, ref m; meas){
		with(m){ proc_cyc = 1_000_000+i*2; DATA_RD = 1000+i; DATA_WR= 
2000+i; INST_FETCH=proc_cyc/2;

L1I_HIT= INST_FETCH-100; L1I_MISS=100;
L1D_HIT= DATA_RD+DATA_WR - 200; L1D_MISS=200;}
}

std.datetime.StopWatch sw;
sw.start();

ref TI getTerm(int i)
{
return meas[i];
}

	// compute the metric results for the above measured sample 
values in parallel

taskPool.amap!(Metrics)(std.algorithm.map!getTerm(samples),results);

TR rv1 = met_l1_miss( meas[0]);
TR rv2 = met_l1_hit( meas[0]);
TR rv3 = met_data_acc( meas[0]);
TR rv4 = met_all_acc( meas[0]);

// how long did this take
long exec_ms = sw.peek().msecs;
writeln("measurements:", meas[0]);
writeln("rv1:", rv1);
writeln("rv2:", rv2);
writeln("rv3:", rv3);
writeln("rv4:", rv4);
writeln("results:", results[1]);
writeln("time:", exec_ms);

}

Re: an example of parallel calculation of metrics

[Jay Norwood via Digitalmars-d-learn]

On Thursday, 1 October 2015 at 18:08:31 UTC, Ali Çehreli wrote:
Makes sense. Please open a bug at least for investigation why 
tuples with named members don't work with amap.


ok, thanks.  I opened the issue.

https://issues.dlang.org/show_bug.cgi?id=15134

help me learn to read documentation

[Robin via Digitalmars-d-learn]

Hi. I like to learn programming by examples but I need help 
learning how to read documentation. I have some idea of how it 
works in some aspects but in others i get completely stuck 
because there are no examples or code snippets.


I am using dgame (dgame-dev.de) and im reading the documentation 
for changing the background text of my font in my program.
I have the basic code for font creation but i need to make 
changes to the colors.


import std.stdio;
import std.system;

import Dgame.System;
import Dgame.Window;
import Dgame.Graphic;
import Dgame.Audio;
import Dgame.Math;

void main()
{
 Font dejavu = Font("resources/dejavu.ttf", 12);
 Text CurrentFps = new Text(dejavu);

 ..window loop
}

The documentation here 
(http://dgame-dev.de/index.php?controller=learn=package=graphic=Text=0.6)...
gives me the Text() class but i dont know how to use "foreground, 
background, and Font mode" or at least turn it into usable syntax.

Re: an example of parallel calculation of metrics

[Jay Norwood via Digitalmars-d-learn]

On Thursday, 1 October 2015 at 18:08:31 UTC, Ali Çehreli wrote:
However, if you prove to yourself that the result tuple and 
your struct have the same memory layout, you can cast the tuple 
slice to struct slice after calling amap:


After re-reading your explanation, I see that the problem is only 
that the results needs to be a Tuple.  It works with named tuple 
members in this example as the result and array of struct as the 
input.  I'll re-check if the multi-member result also works with 
named members.  I'll update the issue report.


import std.meta;
import std.stdio;

// define some input measurement sample tuples and output metric 
tuples


struct TI {long L1I_MISS; long L1D_MISS; }
alias TO = Tuple!(long, "raw");

// various metric definitions
// using Tuples with defined names for each member, and use the 
names here in the metrics.
TO met_l1_miss ( ref TI m){ TO rv;  rv.raw = 
m.L1I_MISS+m.L1D_MISS; return rv; }


// a convenience to use all the metrics above as a list
alias Metrics = AliasSeq!(met_l1_miss);

void main(string[] argv)
{
auto samples = iota(100);
auto meas = new TI[samples.length];
auto results = new TO[samples.length];

// Initialize some values for the measured samples
foreach(i, ref m; meas){
m.L1D_MISS= 100+i; m.L1I_MISS=100-i;
}

ref TI getTerm(int i)
{
return meas[i];
}

	// compute the metric results for the above measured sample 
values in parallel

taskPool.amap!(Metrics)(std.algorithm.map!getTerm(samples),results);

TO rv1 = met_l1_miss( meas[1]);

writeln("measurements:", meas[1]);
writeln("rv1:", rv1);
writeln("results:", results[1]);

}

Re: WTF does "Enforcement failed" actually mean?

[Russel Winder via Digitalmars-d-learn]

On Thu, 2015-10-01 at 08:52 +, John Colvin via Digitalmars-d-learn
wrote:
> […]
> 
> Bug report? Then it'll get fixed.

https://issues.dlang.org/show_bug.cgi?id=15133

Timer running…  ;-)

-- 
Russel.
=
Dr Russel Winder  t: +44 20 7585 2200   voip: sip:russel.win...@ekiga.net
41 Buckmaster Roadm: +44 7770 465 077   xmpp: rus...@winder.org.uk
London SW11 1EN, UK   w: www.russel.org.uk  skype: russel_winder



signature.asc
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Re: an example of parallel calculation of metrics

[Ali Çehreli via Digitalmars-d-learn]

On 10/01/2015 08:56 AM, Jay Norwood wrote:

> Thanks.  My particular use case, working with metric expressions, is
> easier to understand if I use the names.

Makes sense. Please open a bug at least for investigation why tuples 
with named members don't work with amap.


> I converted the use of Tuple
> to struct to see if I could get an easier error msg. Turns out the use
> of struct also results in much cleaner writeln text.
>
> Still has the compile error, though.

We have to live with the fact that amap and friends produce a Tuple 
result if there are multiple functions. A struct won't work.


However, if you prove to yourself that the result tuple and your struct 
have the same memory layout, you can cast the tuple slice to struct 
slice after calling amap:


alias TO_for_amap_result = Tuple!(TR, TR, TR, TR);
struct TO { TR L1_MISS; TR L1_HIT; TR DATA_ACC; TR ALL_ACC;}

// ...

auto results_for_amap = new TO_for_amap_result[samples.length];

// ...


taskPool.amap!(Metrics)(std.algorithm.map!getTerm(samples),results_for_amap);

auto results = cast(TO[])results_for_amap;

// Use 'results' from this point on...

Ali

Re: Interval Arithmetic

[Marco Leise via Digitalmars-d-learn]

Am Thu, 01 Oct 2015 12:03:10 +
schrieb ponce :

> I have a RAII struct to save/restore the FP control word.
> It also handle the SSE control word which unfortunately exist.
> 
> https://github.com/p0nce/dplug/blob/master/plugin/dplug/plugin/fpcontrol.d

Nice to have in Phobos. I assume you have to set the correct
control word depending on whether you perform math on the FPU
or via SSE (as is standard for x86_64)? And I assume further
that DMD always uses FPU math and other compilers provide
flags to switch between FPU and SSE?

-- 
Marco

Re: an example of parallel calculation of metrics

[Jay Norwood via Digitalmars-d-learn]

So, this is a condensed version of the original problem. It looks 
like the problem is that the return value for taskPool.amap can't 
be a tuple of tuples or a tuple of struct.  Either way, it fails 
with the Wrong buffer type error message if I uncomment the 
taskPool line


import std.algorithm, std.parallelism, std.range;
import std.typecons;
import std.meta;
import std.stdio;

// define some input measurement sample tuples and output metric 
tuples


struct TR { long raw; double per_cyc;}
//alias TR = Tuple!(long, "raw", double, "per_cyc");
alias TI = Tuple!(long, "L1I_MISS",long, "L1D_MISS", long, 
"L1D_READ", long, "L1D_WRITE", long, "cycles" );

alias TO = Tuple!(TR, "L1_MISS", TR, "L1D_ACCESS");

// various metric definitions
// using Tuples with defined names for each member, and use the 
names here in the metrics.
TR met_l1_miss ( ref TI m){ TR rv;  rv.raw = 
m.L1I_MISS+m.L1D_MISS;  rv.per_cyc = cast(double)rv.raw/m.cycles; 
return rv; }
TR met_l1_access ( ref TI m){ TR rv;  rv.raw = 
m.L1D_READ+m.L1D_WRITE;  rv.per_cyc = 
cast(double)rv.raw/m.cycles; return rv; }


// a convenience to use all the metrics above as a list
alias Metrics = AliasSeq!(met_l1_miss, met_l1_access);

void main(string[] argv)
{
auto samples = iota(100);
auto meas = new TI[samples.length];
auto results = new TO[samples.length];

// Initialize some values for the measured samples
foreach(i, ref m; meas){
m.L1D_MISS= 100+i; m.L1I_MISS=100-i;
m.L1D_READ= 200+i; m.L1D_WRITE=200-i;
m.cycles= 10+i;
}

ref TI getTerm(int i)
{
return meas[i];
}

	// compute the metric results for the above measured sample 
values in parallel

//taskPool.amap!(Metrics)(std.algorithm.map!getTerm(samples),results);

TR rv1 = met_l1_miss( meas[1]);
TR rv2 = met_l1_access( meas[1]);

writeln("measurements:", meas[1]);
writeln("rv1:", rv1);
writeln("rv2:", rv2);
writeln("results:", results[1]);

}

Re: an example of parallel calculation of metrics

[Jay Norwood via Digitalmars-d-learn]

I re-submitted this as:
https://issues.dlang.org/show_bug.cgi?id=15135

Re: Checking that a template parameter is an enum

[Nordlöw via Digitalmars-d-learn]

On Thursday, 1 October 2015 at 02:06:48 UTC, Fusxfaranto wrote:

/** Returns: true iff all values $(D V) are the same. */
template allSame(V...)  // TODO restrict to values only
{
static if (V.length <= 1)
enum bool allSame = true;
else
enum bool allSame = V[0] == V[1] && allSame!(V[1..$]);
}


std.traits to the rescue!

http://dlang.org/phobos/std_traits.html#isExpressions

Using isExpressions!V as a template constraint looks like the 
behavior you're looking for.


Thanks!

BTW: Is there some way to turn the recursive definition of 
`allSame`


template allSame(V...)
if (isExpressions!(V))
{
static if (V.length <= 1)
enum allSame = true;
else
enum allSame = V[0] == V[1] && allSame!(V[1..$]);
}

into an iterative definition?

Re: Checking that a template parameter is an enum

[Nordlöw via Digitalmars-d-learn]

On Thursday, 1 October 2015 at 02:06:48 UTC, Fusxfaranto wrote:

/** Returns: true iff all values $(D V) are the same. */
template allSame(V...)  // TODO restrict to values only
{
static if (V.length <= 1)
enum bool allSame = true;
else
enum bool allSame = V[0] == V[1] && allSame!(V[1..$]);
}


std.traits to the rescue!

http://dlang.org/phobos/std_traits.html#isExpressions

Using isExpressions!V as a template constraint looks like the 
behavior you're looking for.


Thanks!

BTW: Is there some way to turn the recursive definition of 
`allSame` into an iterative definition?

Re: Checking that a template parameter is an enum

[Ali Çehreli via Digitalmars-d-learn]

On 10/01/2015 03:26 PM, Nordlöw wrote:

On Thursday, 1 October 2015 at 02:06:48 UTC, Fusxfaranto wrote:

/** Returns: true iff all values $(D V) are the same. */
template allSame(V...)  // TODO restrict to values only
{
static if (V.length <= 1)
enum bool allSame = true;
else
enum bool allSame = V[0] == V[1] && allSame!(V[1..$]);
}


std.traits to the rescue!

http://dlang.org/phobos/std_traits.html#isExpressions

Using isExpressions!V as a template constraint looks like the behavior
you're looking for.


Thanks!

BTW: Is there some way to turn the recursive definition of `allSame`

template allSame(V...)
 if (isExpressions!(V))
{
 static if (V.length <= 1)
 enum allSame = true;
 else
 enum allSame = V[0] == V[1] && allSame!(V[1..$]);
}

into an iterative definition?


Very quickly:

import std.traits;

template allSame(V...)
if (isExpressions!(V))
{
bool impl_(V...)() {
static if (V.length > 1) {
foreach (i, _; V[0 .. $ - 1]) {
if (V[i] != V[i + 1]) {
return false;
}
}

return true;

} else {
return true;
}
}

enum allSame = impl_!V();
}

unittest
{
static assert( allSame!());
static assert( allSame!(42));
static assert( allSame!(42, 42, 42));
static assert(!allSame!(42, 43, 42));
}

Ali

Re: an example of parallel calculation of metrics

[Jay Norwood via Digitalmars-d-learn]

This is another attempt with the metric parallel processing. This 
uses the results only to return an int value, which could be used 
later as an error return value.  The metric value locations are 
now allocated as a part of the input measurement values tuple.


The Tuple vs struct definitions seem to have a big difference in 
default output formatting.



import std.algorithm, std.parallelism, std.range;
import std.typecons;
import std.meta;
import std.stdio;

// define some input measurement sample tuples and output metric 
tuples

alias TR = Tuple!(long,"raw",double, "per_cycle");
//struct TR {long raw; double per_cycle;}
alias TO = Tuple!(TR, "l1_miss", TR, "l1_access" );
//struct TO {TR l1_miss; TR l1_access; };
alias TI = Tuple!(long, "L1I_MISS",long, "L1D_MISS", long, 
"L1D_READ", long, "L1D_WRITE", long, "cycles", TO, "res");


// various metric definitions
// using Tuples with defined names for each member, and use the 
names here in the metrics.

long met_l1_miss ( ref TI m){  return m.L1I_MISS + m.L1D_MISS; }
long met_l1_access ( ref TI m){  return  m.L1D_READ + 
m.L1D_WRITE; }


int met_all (ref TI m) {

with (m.res){
 l1_miss.raw = met_l1_miss(m);
 l1_access.raw = met_l1_access(m);
	 l1_miss.per_cycle =  (m.cycles == 0)? double.nan : l1_miss.raw 
/ cast(double)m.cycles;
	 l1_access.per_cycle = (m.cycles == 0)? double.nan : 
l1_access.raw / cast(double)m.cycles;

}
return 0;
}

// a convenience to use all the metrics above as a list
alias Metrics = AliasSeq!(met_all);

void main(string[] argv)
{
auto samples = iota(100);
auto meas = new TI[samples.length];
auto results = new int[samples.length];

// Initialize some values for the measured samples
foreach(i, ref m; meas){
m.L1D_MISS= 100+i; m.L1I_MISS=100-i;
m.L1D_READ= 200+i; m.L1D_WRITE=200-i;
m.cycles= 10+i;
}

ref TI getTerm(int i)
{
return meas[i];
}

	// compute the metric results for the above measured sample 
values in parallel

taskPool.amap!(Metrics)(std.algorithm.map!getTerm(samples),results);


writeln("measurements:", meas[1]);
foreach(ref m; meas){
writeln(m.res);
}

}

Re: Checking that a template parameter is an enum

[Nordlöw via Digitalmars-d-learn]

On Thursday, 1 October 2015 at 22:37:57 UTC, Ali Çehreli wrote:

Very quickly:

import std.traits;

template allSame(V...)
if (isExpressions!(V))
{
bool impl_(V...)() {
static if (V.length > 1) {
foreach (i, _; V[0 .. $ - 1]) {
if (V[i] != V[i + 1]) {
return false;
}
}

return true;

} else {
return true;
}
}

enum allSame = impl_!V();
}


Will this spare memory in DMD? If so there are a few traits that 
should be update accordingly, for instance `allSatisfy` and 
`anySatisfy`.


Thanks!

Re: WTF does "Enforcement failed" actually mean?

[Ali Çehreli via Digitalmars-d-learn]

On 09/30/2015 10:46 PM, Russel Winder via Digitalmars-d-learn wrote:

I have the code:

reduce!"a+b"(x)

where x is a int[] and I get an exception "Enforcement failed" at run
time. This gives me enough information to say ¿que?



It's coming from the following no-message enforce():

enforce(!r.empty);


https://github.com/D-Programming-Language/phobos/blob/master/std/algorithm/iteration.d#L2481

You are using the no-seed version of reduce(), which uses the first 
element as seed, which means that the range cannot be empty.


Ali

Re: an example of parallel calculation of metrics

[Ali Çehreli via Digitalmars-d-learn]

On 09/30/2015 09:15 PM, Jay Norwood wrote:

> alias TO = Tuple!(TR,"L1_MISS", TR, "L1_HIT", TR,"DATA_ACC", 
TR,"ALL_ACC");


Looks like a bug. Workaround: Get rid of member names there:

alias TO = Tuple!(TR, TR, TR, TR);

> 
//taskPool.amap!(Metrics)(std.algorithm.map!getTerm(samples),results);


For some reason, having member names prevents 'results' passing one of 
amap's requirements. The following check in std.parallelism thinks that 
'results' does not have random assignable elements if it is a Tuple with 
member names.


else static if(randAssignable!(Args[$ - 1]) && Args.length > 1)
{
static assert(0, "Wrong buffer type.");
}

Ali

Re: address of overloaded function

[Jacob Carlborg via Digitalmars-d-learn]

On 2015-10-01 00:48, Freddy wrote:

How do you take the address of a specific overloaded function. This
won't compile
---
import std.range;

void main()
{
 ForwardAssignable!int range;
 int delegate() @property get = 
 void delegate(int) @property set = 
}
---


Not sure why that doesn't work. This works:

int foo () { return 0; }
void foo (int) {}

void main()
{
int function () a = 
void function (int) b = 
}

--
/Jacob Carlborg

Re: WTF does "Enforcement failed" actually mean?

[Russel Winder via Digitalmars-d-learn]

On Wed, 2015-09-30 at 23:35 -0700, Ali Çehreli via Digitalmars-d-learn
wrote:
> On 09/30/2015 10:46 PM, Russel Winder via Digitalmars-d-learn wrote:
> > I have the code:
> > 
> > reduce!"a+b"(x)
> > 
> > where x is a int[] and I get an exception "Enforcement failed" at
> > run
> > time. This gives me enough information to say ¿que?
> > 
> 
> It's coming from the following no-message enforce():
> 
>  enforce(!r.empty);
> 
>  
> https://github.com/D-Programming-Language/phobos/blob/master/std/algo
> rithm/iteration.d#L2481
> 
> You are using the no-seed version of reduce(), which uses the first 
> element as seed, which means that the range cannot be empty.

Well that explanation (*) makes it abundantly clear that the error
reporting from this part of Phobos is distinctly substandard, let alone
below par.


(*) Which is clear and informative!
-- 
Russel.
=
Dr Russel Winder  t: +44 20 7585 2200   voip: sip:russel.win...@ekiga.net
41 Buckmaster Roadm: +44 7770 465 077   xmpp: rus...@winder.org.uk
London SW11 1EN, UK   w: www.russel.org.uk  skype: russel_winder



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Description: This is a digitally signed message part

Re: help me learn to read documentation

[Adam D. Ruppe via Digitalmars-d-learn]

On Thursday, 1 October 2015 at 19:15:39 UTC, Robin wrote:
The documentation here 
(http://dgame-dev.de/index.php?controller=learn=package=graphic=Text=0.6)...
gives me the Text() class but i dont know how to use 
"foreground, background, and Font mode" or at least turn it 
into usable syntax.


Those describe simple class members, so you can set them through 
assignment:


 Text CurrentFps = new Text(dejavu);
 // change to white on black
 CurrentFps.foreground = Color4b.White;
 CurrentFps.background = Color4b.Black;
 // change mode
 CurrentFps.mode = Font.Mode.Shaded;


I haven't actually used this library, but since the doc describes 
it with variable syntax (`Color4b foreground;`) that means you 
should be able to just assign to them like ordinary object member 
variables.

Re: Checking that a template parameter is an enum

[Meta via Digitalmars-d-learn]

On Thursday, 1 October 2015 at 22:41:21 UTC, Nordlöw wrote:
Will this spare memory in DMD? If so there are a few traits 
that should be update accordingly, for instance `allSatisfy` 
and `anySatisfy`.


Thanks!


Highly doubtful as CTFE already allocates like there's no 
tomorrow.

Re: help me learn to read documentation

[Robin via Digitalmars-d-learn]

On Friday, 2 October 2015 at 01:20:50 UTC, Adam D. Ruppe wrote:

On Thursday, 1 October 2015 at 19:15:39 UTC, Robin wrote:

[...]


Those describe simple class members, so you can set them 
through assignment:


 Text CurrentFps = new Text(dejavu);
 // change to white on black
 CurrentFps.foreground = Color4b.White;
 CurrentFps.background = Color4b.Black;
 // change mode
 CurrentFps.mode = Font.Mode.Shaded;


I haven't actually used this library, but since the doc 
describes it with variable syntax (`Color4b foreground;`) that 
means you should be able to just assign to them like ordinary 
object member variables.


Wow, thank you so much. I have never seen code like that before 
but the documentation there made me scratch my head.


Thank you.

How to break gdb on D exception ?

[BBasile via Digitalmars-d-learn]

Currently it works fine when throwing with core.exception 
functions 'on', like explained in the wiki, for example:

---
break onFinalizeError
---

But I can't manage to break when a new Exception instance is 
thrown in the code:


---
throw new Exception("ouch");
---

none of the following GB commands work:

---
catch catch
catch throw
catch signal all
catch signal
---

It looks like there are some tricks, like put a break on the vtbl 
of the base throwable class (no quite sure about this to be 
honest...)


Does anyone manage this ?

Re: How to break gdb on D exception ?

[BBasile via Digitalmars-d-learn]

On Friday, 2 October 2015 at 04:24:11 UTC, Adam D. Ruppe wrote:

On Friday, 2 October 2015 at 03:58:45 UTC, BBasile wrote:

none of the following GB commands work:


give

break d_throw

or maybe `break d_throwc` a try


unfortunately it doesn't work, i get

---
(gdb) Function "d_throw"/"d_throwc" not defined.

Re: How to break gdb on D exception ?

[BBasile via Digitalmars-d-learn]

On Friday, 2 October 2015 at 04:46:51 UTC, BBasile wrote:

On Friday, 2 October 2015 at 04:24:11 UTC, Adam D. Ruppe wrote:

On Friday, 2 October 2015 at 03:58:45 UTC, BBasile wrote:

none of the following GB commands work:


give

break d_throw

or maybe `break d_throwc` a try


unfortunately it doesn't work, i get

---
(gdb) Function "d_throw"/"d_throwc" not defined.


it was almost that actually,
'break _d_throwc

Re: How to break gdb on D exception ?

[BBasile via Digitalmars-d-learn]

On Friday, 2 October 2015 at 03:58:45 UTC, BBasile wrote:

Does anyone manage this ?

I meant: Does anyone master this ?

Re: How to break gdb on D exception ?

[Adam D. Ruppe via Digitalmars-d-learn]

On Friday, 2 October 2015 at 03:58:45 UTC, BBasile wrote:

none of the following GB commands work:


give

break d_throw

or maybe `break d_throwc` a try

How to use std.experimental.logger?

[Panke via Digitalmars-d-learn]

I tried it on Windows today using the latest DMD installer, all 
default logger and settings.


I get: safe function [...].logImplf cannot call system function 
'std.format.formattedWrite!(MsgRange, char, 
Result!()).formattedWrite'


How do I make formatted logging work?

Re: How to use std.experimental.logger?

[Adrian Matoga via Digitalmars-d-learn]

On Thursday, 1 October 2015 at 08:21:35 UTC, Panke wrote:
I tried it on Windows today using the latest DMD installer, all 
default logger and settings.


I get: safe function [...].logImplf cannot call system function 
'std.format.formattedWrite!(MsgRange, char, 
Result!()).formattedWrite'


How do I make formatted logging work?


Would be easier to diagnose your problem if you pasted your code 
and uncut complaint from the compiler.


Anyway, the following works, so it may give you a hint:

$ cat log.d
import std.experimental.logger;

void main()
{
logf("just log %s and %d", "this", 1337);
}
$ dmd log.d
$ ./log
2015-10-01T11:23:57.291:log.d:main:5 just log this and 1337

Re: WTF does "Enforcement failed" actually mean?

[John Colvin via Digitalmars-d-learn]

On Thursday, 1 October 2015 at 07:08:00 UTC, Russel Winder wrote:
On Wed, 2015-09-30 at 23:35 -0700, Ali Çehreli via 
Digitalmars-d-learn wrote:
On 09/30/2015 10:46 PM, Russel Winder via Digitalmars-d-learn 
wrote:

> [...]

It's coming from the following no-message enforce():

 enforce(!r.empty);


https://github.com/D-Programming-Language/phobos/blob/master/std/algo
rithm/iteration.d#L2481

You are using the no-seed version of reduce(), which uses the 
first element as seed, which means that the range cannot be 
empty.


Well that explanation (*) makes it abundantly clear that the 
error reporting from this part of Phobos is distinctly 
substandard, let alone below par.



(*) Which is clear and informative!


Bug report? Then it'll get fixed.

Re: Range of variables

[Atila Neves via Digitalmars-d-learn]

On Wednesday, 30 September 2015 at 20:11:56 UTC, Freddy wrote:

Is there a way to make a range of a variables lazily?
---
int var1;
int var2;
void func()
{
int var3;
auto range = /*range of var1,var2,var3*/ ;
}
---


std.range.iota

Atila