Re: dlang.org/spec/function.html#pure-functions example
On Thursday, 12 October 2023 at 21:20:44 UTC, Jonathan M Davis wrote: look like? Types can have static members. Basically what it comes down to is that outside of immutable data, pure functions only have access to their arguments and to what they can access via their arguments (be it by getting pointers from those arguments or calling other pure functions on them). - Jonathan M Davis Can I say in the general sense that when the word static is used it means that something is defined/declared at compile time?
Re: dlang.org/spec/function.html#pure-functions example
On Thursday, 12 October 2023 at 21:20:44 UTC, Jonathan M Davis wrote: Thanks Jonathan
Re: extern (c)
On Wednesday, 11 October 2023 at 12:54:53 UTC, user1234 wrote: `extern(C)` on module level functions affect the mangling and the calling convention. - Mangling is used by the linker to link symbols between objects. - Calling convention affects the compiler backend in how code is generated for a CALL instruction. So C doesn't use name mangling and extern (C) in a D prog would turn off D mangling thereby allowing C and D object files to be linked together? I didn't know C and D had different calling conventions...i.e. different ABI's?
extern (c)
What does the extern (c) attribute(?) do? Does it tell the compiler/linker to build the function like a C compiler would build a C function? If so what does that mean? Does it tell the compiler/linker to let C functions know it exists? If so what does that mean? Is it meant for the compiler or linker or both? Thanks for any assistance.
Re: "macro" expansion to build switch case code
On Sunday, 2 July 2023 at 20:27:47 UTC, Steven Schveighoffer
wrote:
On 7/2/23 1:02 PM, Paul wrote:
[...]
Use a static foreach:
```d
import std.traits; // for FieldNameTuple. there are other ways,
but this is the most straightforward
switchlabel: // this is needed for break inside a static foreach
final switch(s) {
static foreach(mem; FieldNameTuple!myS) {
case mem ~ mem:
__traits(getMember, this, mem) += n;
break switchalbel;
}
}
```
-Steve
Perfect. Thanks Steve!
"macro" expansion to build switch case code
I have a struct similar to the following example. I'd like to
build an adder method without having to code the whole method.
How do I use the D language to do this? Template, mixins,
CTFE..all of them?
```d
struct myS {
int a, b, c, d, e, f, g, h, i;
adder(string s, int n) {
final switch (s) {
case "aa" :
a += n; break;
case "bb" :
b += n; break;
...
```
Thanks for any assistance.
Re: key membership in multi-dimensional assoc. array
On Thursday, 15 June 2023 at 02:21:16 UTC, Steven Schveighoffer
wrote:
Not in as short code. You could write a helper though:
```d
auto deepIn(V, K, Keys...)(V[K] aa, Keys keys) if (Keys.length
> 0)
{
auto v = keys[0] in aa;
static if(keys.length == 1)
return v;
else
return v ? deepIn(*v, keys[1 .. $]) : null;
}
if(auto v = cubelist.deepIn(xKey, yKey, zKey)) { // v now
points at the value
}
```
-Steve
Thanks Steve.
key membership in multi-dimensional assoc. array
I found I can check for key membership in a multi-D aa...
```d
byte zKey = someval;
byte[byte][byte][byte] cubelist;
foreach(byte xK, yzcubelist; cubelist) {
foreach(byte yK, zcubelist; yzcubelist) {
foreach(byte zK, val; zcubelist) {
```
with this expression...
```d
if(zKey in cubelist[xK][yK])
```
Is there a way to check for membership in the x & y dimensions?
```d
if(yKey in cubelist[xK] ??? [zK])
```
*Thanks in advance for any ideas or solutions.*
Re: Union with bits ?
On Wednesday, 14 June 2023 at 22:44:41 UTC, Ali Çehreli wrote: By the way, the string that bitfields() generates can be visualized by simply printing it: const code = bitfields!( ubyte, "A", 1, ubyte, "B", 1, ubyte, "C", 1, ubyte, "padding", 5,); writeln(code); The output is not pretty for the human eye but those are basically the getters and setters that Adam D Ruppe mentioned. Ali Excellent help. Thanks Adam and Ali.
Re: Union with bits ?
On Wednesday, 14 June 2023 at 14:43:58 UTC, Ali Çehreli wrote:
D's string mixin syntax may not be the best, the implementation
may be slower than necessary, and the concept may be strange
(not macros but very similar) but I still find phobos's
bifields to be brilliant.
https://dlang.org/phobos/std_bitmanip.html#bitfields
import std.bitmanip;
struct MyStruct {
union {
ubyte status;
mixin(bitfields!(
ubyte, "A", 1,
ubyte, "B", 1,
ubyte, "C", 1,
ubyte, "padding", 5,));
}
}
void main() {
auto m = MyStruct();
m.B = 1;
assert(m.status == 2);
}
Ali
Thanks Ali! I believe this is what I'm looking for. I searched
our website and library but somehow missed this.
Question: Why do you say "may be slower than necessary"? Do you
mean compile or runtime or both?
Union with bits ?
I would like to have labeled bits in a union with a ubyte.
Something like this:
```d
struct MyStruct {
union {
ubyte status;
bit A, B, C…etc
}
}
```
Is something like this possible?
Thanks
Re: regex matching but not capturing
On Thursday, 6 April 2023 at 16:27:23 UTC, Alex Bryan wrote:
My understanding browsing the documentation is the matchAll
returns a range of Captures (struct documented at
https://dlang.org/phobos/std_regex.html#Captures). In your for
loop I think c[0] will contain the current full match (current
line that matches), c[1] will contain the first captured match
("AA" for first line), c.front[2] will contain "0" for first
line, etc.
Thanks Alex. Read some more and tried some different ways to
access those repetitive ", cc" s on the end. I don't think my
regex is capturing them.
regex matching but not capturing
My regex is matching but doesnt seem to be capturing. You may
recognize this from the AOC challenges.
file contains...
**Valve AA has flow rate=0; tunnels lead to valves DD, II, BB**
**Valve BB has flow rate=13; tunnels lead to valves CC, AA**
**Valve CC has flow rate=2; tunnels lead to valves DD, BB**
**... etc**
```d
auto s = readText(filename);
auto ctr = ctRegex!(`Valve ([A-Z]{2}).*=(\d+).+valves(,*
[A-Z]{2})+`);
foreach(c;matchAll(s, ctr)) {
fo.writeln(c);
}
```
produces...
**["Valve AA has flow rate=0; tunnels lead to valves DD, II, BB",
"AA", "0", ", BB"]**
**["Valve BB has flow rate=13; tunnels lead to valves CC, AA",
"BB", "13", ", AA"]**
**["Valve CC has flow rate=2; tunnels lead to valves DD, BB",
"CC", "2", ", BB"]**
what I'm attempting to achieve and expect is, for instance, on
the 1st line...
[lead to valves DD, II, BB", "AA", "0", **", DD", ", II", ",
BB"]**
Re: foreach (i; taskPool.parallel(0..2_000_000)
On Thursday, 6 April 2023 at 01:44:15 UTC, H. S. Teoh wrote: D ranges are conceptually sequential, but the actual underlying memory access patterns depends on the concrete type at runtime. An array's elements are stored sequentially in memory, and arrays are ranges. But a linked-list can also have a range interface, yet its elements may be stored in non-consecutive memory locations. So the concrete type matters here; the range API only gives you conceptual sequentiality, it does not guarantee physically sequential memory access. Very helpful Teoh. Thanks again.
Re: foreach (i; taskPool.parallel(0..2_000_000)
On Wednesday, 5 April 2023 at 23:06:54 UTC, H. S. Teoh wrote: So your data structures and algorithms should be designed in a way that takes advantage of linear access where possible. T Yes I understand, basically, what's going on in hardware. I just wasn't sure if the access type was linked to the container type. It seems obvious now, since you've both made it clear, that it also depends on how I'm accessing my container. Having said all of this, isn't a D 'range' fundamentally a sequential access container (i.e popFront) ?
Re: foreach (i; taskPool.parallel(0..2_000_000)
On Tuesday, 4 April 2023 at 22:20:52 UTC, H. S. Teoh wrote: Best practices for arrays in hot loops: - Avoid appending if possible; instead, pre-allocate outside the loop. - Where possible, reuse existing arrays instead of discarding old ones and allocating new ones. - Use slices where possible instead of making copies of subarrays (this esp. applies to strings). - Where possible, prefer sequential access over random access (take advantage of the CPU cache hierarchy). Thanks for sharing Teoh! Very helpful. would this be random access? for(size_t i; iusing indices? ...and this be sequential foreach(a;arr) ? or would they have to be completely different kinds of containers? a dlang 'range' vs arr[]?
Re: foreach (i; taskPool.parallel(0..2_000_000)
On Monday, 3 April 2023 at 23:50:48 UTC, Steven Schveighoffer wrote: So what you need is inside `createSpansOfNoBeacons`, take as a reference a `ref Span[MAX_SPANS]`, and have it return a `Span[]` that is a slice of that which was "alocated". See if this helps. Well Steven just making the change you said reduced the execution time from ~6-7 secs to ~3 secs. Then, including the 'parallel' in the foreach statement took it down to ~1 sec. Boy lesson learned in appending-to and zeroing dynamic arrays in a hot loop!
Re: foreach (i; taskPool.parallel(0..2_000_000)
On Monday, 3 April 2023 at 23:13:58 UTC, Steven Schveighoffer
wrote:
Yeah, please post.
```d
module aoc2215b2;
import std.stdio;
import std.file: readText;
import std.conv: to;
import std.math: abs;
import std.traits;
import std.parallelism;
import std.range;
import core.time: MonoTime;
// Timed main()
vvv
void main(string[] args) {
auto progStartTime = MonoTime.currTime;
//-
string filename = args.length > 1 ? args[1] : "aoc2215a.data";
CommPair[] commPair;
ulong x,y;
// read file that has data sets in the form of x,y coordinate
pairs
// for each sensor-beacon pair. Create on array of structs to
hold
// this information.
loadFileDataIntoArrayOfStructs(commPair, filename);
foreach(int lineOfInterest;parallel(iota(0,4_000_001))) {
Span[] span; // A section of line-of-interest coordinates where
no other beacons are present.
const spanReserve = span.reserve(50);
createSpansOfNoBeacons(lineOfInterest,commPair,span);
// if spans overlap, combine them into a single span and mark
// the other spans !inUse.
combineOverlappingSpans(span);
// look for a line that doesn't have 4,000,001 locations
accounted for
if(beaconFreeLocations(span) < 4_000_001) {
// find the location that is not accounted for
foreach(ulong i;0..4_000_000) {
bool found = false;
foreach(sp;span) {
if(i >= sp.xLow && i <= sp.xHigh) {
found = true;
break;
}
}
if(!found) {
x = i; y = lineOfInterest;
break;
}
}
}
}
writeln(x," ",y);
//-
auto progEndTime = MonoTime.currTime;
writeln(progEndTime - progStartTime);
}
// Timed main()
^^^
struct CommPair {
int sx,sy,bx,by;
int manhattanDistance;
}
void loadFileDataIntoArrayOfStructs(ref CommPair[] commPair,
string filename) {
import std.regex;
auto s = readText(filename);
auto ctr = ctRegex!(`x=(-*\d+), y=(-*\d+):.*x=(-*\d+),
y=(-*\d+)`);
CommPair cptemp;
foreach (c; matchAll(s, ctr)) {
cptemp.sx = to!int(c[1]);
cptemp.sy = to!int(c[2]);
cptemp.bx = to!int(c[3]);
cptemp.by = to!int(c[4]);
cptemp.manhattanDistance = abs(cptemp.sx-cptemp.bx) +
abs(cptemp.sy-cptemp.by);
commPair ~= cptemp;
}
}
struct Span {
int xLow, xHigh;
bool inUse = true;
}
void createSpansOfNoBeacons(int lineOfInterest, CommPair[]
commPair,ref Span[] span) {
foreach(size_t i,cp;commPair) {
int distanceToLineOfInterest = abs(cp.sy - lineOfInterest);
if(cp.manhattanDistance >= distanceToLineOfInterest) {
int xLow = cp.sx - (cp.manhattanDistance -
distanceToLineOfInterest);
int xHigh = cp.sx + (cp.manhattanDistance -
distanceToLineOfInterest);
span ~= Span(xLow,xHigh);
}
}
}
void combineOverlappingSpans(ref Span[] span) {
bool combinedSpansThisCycle = true;
while(combinedSpansThisCycle) {
combinedSpansThisCycle = false;
for(size_t i=0; i < span.length-1; i++) {
if(!span[i].inUse) continue;
for(size_t j=i+1; j < span.length; j++) {
if(!span[j].inUse) continue;
// if one span overlaps with the other, combine them into one
span
if(spanIContainedInSpanJ(span[i],span[j]) ||
spanJContainedInSpanI(span[i],span[j])) {
span[i].xLow = span[i].xLow < span[j].xLow ? span[i].xLow
: span[j].xLow;
span[i].xHigh = span[i].xHigh > span[j].xHigh ?
span[i].xHigh : span[j].xHigh;
span[j].inUse = false;
combinedSpansThisCycle = true;
// after combining two spans, perform
bounds checking
// 15 part b limits the search between
0 and 4,000,000
span[i].xLow = span[i].xLow < 0 ? 0 :
span[i].xLow;
span[i].xHigh = span[i].xHigh > 4_000_000 ? 4_000_000 :
span[i].xHigh;
Re: foreach (i; taskPool.parallel(0..2_000_000)
On Monday, 3 April 2023 at 22:24:18 UTC, Steven Schveighoffer wrote: If your `foreach` body takes a global lock (like `writeln(i);`), then it's not going to run any faster (probably slower actually). **Ok I did have some debug writelns I commented out.** And did it help? **No** My program is about 140 lines Steven. Its just one of the Advent of Code challenges. Could I past the whole program here and see what you think? Thanks for your assistance...much appreciated.
Re: foreach (i; taskPool.parallel(0..2_000_000)
On Sunday, 2 April 2023 at 15:32:05 UTC, Steven Schveighoffer wrote: It's important to note that parallel doesn't iterate the range in parallel, it just runs the body in parallel limited by your CPU count. **?!?** If your `foreach` body takes a global lock (like `writeln(i);`), then it's not going to run any faster (probably slower actually). **Ok I did have some debug writelns I commented out.** If you can disclose more about what you are trying to do, it would be helpful. **This seems like it would be a lot of code and explaining but let me think about how to summarize.** Also make sure you have more than one logical CPU. **I have 8.**
Re: foreach (i; taskPool.parallel(0..2_000_000)
On Saturday, 1 April 2023 at 18:30:32 UTC, Steven Schveighoffer wrote: On 4/1/23 2:25 PM, Paul wrote: ```d import std.range; foreach(; iota(0, 2_000_000).parallel) ``` -Steve Is there a way to tell if the parallelism actually divided up the work? Both versions of my program run in the same time ~6 secs.
Re: foreach (i; taskPool.parallel(0..2_000_000)
```d import std.range; foreach(; iota(0, 2_000_000).parallel) ``` -Steve Is there a way to verify that it split up the work in to tasks/threads ...? The example you gave me works...compiles w/o errors but the execution time is the same as the non-parallel version. They both take about 6 secs to execute. totalCPUs tells me I have 8 CPUs available.
Re: foreach (i; taskPool.parallel(0..2_000_000)
Thanks Steve.
foreach (i; taskPool.parallel(0..2_000_000)
Thanks in advance for any assistance. As the subject line suggests can I do something like? : ```d foreach (i; taskPool.parallel(0..2_000_000)) ``` Obviously this exact syntax doesn't work but I think it expresses the gist of my challenge.
New to profiling: dmd -profile; ldc2 --fdmd-trace-functions
Thanks in advance for any assistance. As the subject line states I'm just now trying to learn profiling. I have a very small program with 1/2 dozen functions and would like to see where the cpu is spending the most time. I've tried both of these lines with identical results: **ldc2 --fdmd-trace-functions myprog.d** **dmd -profile myprog.d** The result is that no 'trace' files are generatedas far as I can tell. When I run myprog.exe it generates no errors, runs very quickly, and does not do what it previously was doing. **ldc2 --version** **LDC - the LLVM D compiler (1.30.0-git-5fd86e5):** **based on DMD v2.100.1 and LLVM 14.0.3** **dmd --version** **DMD64 D Compiler v2.100.2-dirty**
Re: Read a text file at once for regex searching
On Monday, 20 March 2023 at 17:47:19 UTC, Adam D Ruppe wrote:
On Monday, 20 March 2023 at 17:42:17 UTC, Paul wrote:
Do we have some such function in our std library?
Try
static import std.file;
string s = std.file.readText("filename.txt");
http://phobos.dpldocs.info/std.file.readText.html
Thanks Adam.
Read a text file at once for regex searching
I've been looking through our Library documentation and having trouble finding what I want. **I'd like to read a text file in all at once** and do some searching and analytics on it instead of reading it bit by bit or line by line. Do we have some such function in our std library? Thanks in advance.
Re: Assign to Array Column
On Wednesday, 1 February 2023 at 03:45:11 UTC, Salih Dincer wrote: On Tuesday, 31 January 2023 at 01:04:41 UTC, Paul wrote: Can I perform a similar assignment to the column? This, myArr[][0] = 5, doesn't work. Of course, this question has a short answer and a long answer. So the issue is more about column-major. I am someone who likes to talk with codes. In fact, everything is side by side in memory. This example (something like array) covers the issue: Thanks Salih. Much appreciated.
Re: Address of a class object
On Thursday, 5 January 2023 at 05:59:26 UTC, Ali Çehreli wrote: On 1/4/23 20:04, Paul wrote: >> (Again, there is no problem here; we are just learning.) >> Ali > > Do I have this much right? > ..with this output? Looks good to me. While we're here, you can force the class objects to be on the stack as well: scope MyClassVar1 = new MyClass(); I replaced 'auto' with 'scope'. Ali I was tinkering with this use of 'scope' and the math for pointer location, object size, and alignment started working out.
Assign to Array Column
Greetings, for an array byte[3][3] myArr, I can code myArr[0] = 5 and have: 5,5,5 0,0,0 0,0,0 Can I perform a similar assignment to the column? This, myArr[][0] = 5, doesn't work. Thanks!
Re: Coding Challenges - Dlang or Generic
On Thursday, 12 January 2023 at 20:28:26 UTC, Christian Köstlin wrote: For this years advent-of-code Steven Schveighoffer (https://github.com /schveiguy/adventofcode/tree/master/2022) has a complete set of dlang solutions. Kind regards, Christian Very helpful. Thanks Christian.
Re: Coding Challenges - Dlang or Generic
On Tuesday, 10 January 2023 at 01:31:28 UTC, Ali Çehreli wrote: On 1/9/23 16:17, Paul wrote: > coding challenges Perhaps the following two? https://rosettacode.org/ https://adventofcode.com/ Ali Excellent. Thanks.
Re: Coding Challenges - Dlang or Generic
On Tuesday, 10 January 2023 at 06:45:40 UTC, Siarhei Siamashka wrote: ... What kind of D class is that? Are you learning D language in a school or university? Or is it some kind of online language course? ... I don't know if there are rules about sharing links and such but its a site called https://www.educative.io/learn. There are two D courses. I just finished the second class. The business model on 'Educative' is by subscription with maybe one week or month free trial. So you can get as many certificates as you can complete during your subscription. So I don't know how much weight the certificates carry but I have two D course certificates.
Re: Coding Challenges - Dlang or Generic
On Tuesday, 10 January 2023 at 01:22:33 UTC, H. S. Teoh wrote: ... Here's a challenge. Given an input year, for example, "2023", write a program that outputs (for the corresponding year): ... Code will be graded on readability, unittest coverage, and reusability (how many functions have wide applicability outside of this challenge). ;-) T I think you must have done a blog post or tutorial or something, Teoh, because I've seen this before. Don't let this go to your head :), but I was blown away by the presentation and solution! BTW where is it posted?
Coding Challenges - Dlang or Generic
Greetings Dlang-ers I was wondering if anyone knew of any coding challenges available where the input and output are specified and its left to the programmer to find a solution? Free would be nice but even paid services would be worth considering. I'm taking a D class right now and it has little challenges in the lessons where much of the work is done for you, but I'm thinking of a site/service that is dedicated to these types of challenges (without doing any work for you). I wonder if a site dedicated to Dlang challenges would 'fly'? It would be quite interesting and instructive to see how different coders solved a particular coding problem. Statistics could be generated for each solution (e.g. compile time, execution time, source code size, executable size, @safe, @nogc, readability of source code, helpfulness of comments, etc.). With D's multi-paradigm power it could be fascinating. I know. Someone's going to say why don't YOU do it:) regards,
Re: Address of a class object
On Thursday, 5 January 2023 at 05:59:26 UTC, Ali Çehreli wrote: While we're here, you can force the class objects to be on the stack as well: scope MyClassVar1 = new MyClass(); I replaced 'auto' with 'scope'. Ali Very interesting. Thanks Ali.
Re: Address of a class object
(Again, there is no problem here; we are just learning.)
Ali
Do I have this much right?
```d
import std.stdio, std.traits;
class MyClass {char c;}
void main() {
auto MyInt = 1;
writeln("The address of MyInt is : ",," (stack)");
auto MyClassVar1 = new MyClass();
writeln("The address of MyClassVar1 is: ",,"
(stack)");
auto MyClassVar2 = new MyClass();
writeln("The address of MyClassVar2 is: ",,"
(stack)");
writeln;
auto MyClassObj1 = cast(void*)MyClassVar1;
writeln("The address of MyClassObj1 is: ",MyClassObj1,"
(heap)");
auto MyClassObj2 = cast(void*)MyClassVar2;
writeln("The address of MyClassObj2 is: ",MyClassObj2,"
(heap)");
}
```
..with this output?
```
The address of MyInt is : 1CA1CFFB1C (stack)
The address of MyClassVar1 is: 1CA1CFFB10 (stack)
The address of MyClassVar2 is: 1CA1CFFB08 (stack)
The address of MyClassObj1 is: 1EB93212000 (heap)
The address of MyClassObj2 is: 1EB93212020 (heap)
```
Re: Address of a class object
matheus, using dmd64 on my laptop to compile and run this:
```d
import std.stdio, std.traits;
class MyClass {char[16] c;}
void main() {
writeln(" Size Alignment Type\n",
"=");
size_t size = __traits(classInstanceSize, MyClass);
size_t alignment = classInstanceAlignment!MyClass;
writefln("%4s%8s %s",size, alignment, MyClass.stringof);
// my test code added
auto MyClassO1 = new MyClass();
auto MyClassO2 = new MyClass();
writeln("\nMyClassObj1 MyClassObj2");
writeln(cast(void*)MyClassO1,"\t",cast(void*)MyClassO2);
}
```
I get this:
```
Size Alignment Type
=
32 8 MyClass
MyClassObj1 MyClassObj2
21EF8E22000 21EF8E22020
```
If I change this line to:
```
class MyClass {char[1] c;}
```
I get this:
```
Size Alignment Type
=
17 8 MyClass
MyClassObj1 MyClassObj2
27727202000 27727202020
```
If my size is 17 bytes and my alignment is 8 bytes, shouldn't my
MyClassObj2 in this example be @ 277272020**18** ?
Re: Address of a class object
Thank you, Teoh, Ali, & Matheus
Re: Address of a class object
Thanks all. Yes it seems my understanding and "D" vocabulary are
still a bit confused.
So I'm taking a D course online and was trying to verify what I
was learning. The course example printed out the size and
alignment of types...something close to this:
```d
import std.stdio;
import std.traits;
class MyClass {char c;}
void main() {
writeln(" Size Alignment Type\n",
"=");
size_t size = __traits(classInstanceSize, MyClass);
size_t alignment = classInstanceAlignment!MyClass;
writefln("%4s%8s %s",size, alignment, MyClass.stringof);
// my test code added
MyClass MyClassO1;
MyClass MyClassO2;
writeln("\n",,"\t",);
}
```
...on my laptop it prints...
```
Size Alignment Type
=
9 4 MyClass
4FFB20 4FFB24
```
If the size of MyClass is 9 bytes why do MyClassO1 & O2 addresses
only differ by 4 bytes?
Because those addresses(4FFB20 4FFB24) are the addresses of the
class **variables**, not the addresses of the **objects**
themselves?
So, I guess my question is actually how do I print out the
addresses of the MyClassO1 & O2 objects themselves?
```
Address of a class object
Hello. Thanks for any assistance.
Can I acquire the address of a class object, not a class variable
(i.e. the instantiations of the class) but the object definition
itself?
```d
class MyClass {char c}
...
MyClass MyClassVar;
writeln(); // this compiles
writeln();// this does not
```
Re: _Symbols _with _leading _underscores
Much appreciated...
_Symbols _with _leading _underscores
I see code like this from time to time. Are the leading
underscores significant, in general, in the D language? Is it
just programmer preference? Is it a coding practice, in general,
that is common...even outside of D? Thanks for any assistance.
From:
http://dpldocs.info/this-week-in-d/Blog.Posted_2022_10_10.html#hello-arduino
```d
import ldc.llvmasm;
// Ports from the delay_basic.h in the thing
void _delay_loop_1(ubyte __count) {
// this template param is required to avoid
// assertion `!Call.getType()->isVoidTy() && "Bad inline asm!"'
failed.
__asm!ubyte (
"1: dec $0\n\tbrne 1b",
"=r,0", (__count)
);
}
void _delay_loop_2(ushort __count) {
__asm!ushort (`
1: sbiw $0,1
brne 1b
`,
`=w,0`,
__count);
}
// port from delay.h in arduino thing
enum F_CPU = 1_000_000UL;
// this was _delay_ms but i did something wrong and changed
double to int and i still don't love it
void _delay(int __ms) {
ushort __ticks;
ulong __tmp = (F_CPU * __ms) / 4000;
if(__tmp < 1)
__ticks = 1;
else if(__tmp > 65_535) {
__ticks = cast(ushort) (__ms * 10.0);
while(__ticks) {
_delay_loop_2(cast(ushort) (((F_CPU) / 4e3) / 10));
__ticks--;
}
return;
} else
__ticks = cast(ushort) __tmp;
_delay_loop_2(__ticks);
}
```
Re: Convert int to dchar
On Wednesday, 5 October 2022 at 17:16:29 UTC, H. S. Teoh wrote: For the former: dchar ch = '0' + intValue; This! Thanks Teoh.
Re: Convert int to dchar
Thanks Steve. I need to covert something like this: int myvar = 5; How would I convert myvar to a dchar?
Convert int to dchar
I'm sure I'm making this more difficult than it needs to be. I'm trying to convert an integer to a dchar. The solution below works but seems like overkill. dstring dstrValue = to!dstring(5); dchar dcharValue = to!dchar(dstrValue); ... this, dchar dcharValue = to!dchar(5); ... writes out '\x005' ..or something close to that.
Re: write struct as raw data to file
Vitaliy,
Thanks for your assistance. I was looking at your serialization
package. Is your example correct?
struct MyStruct {
ubyte mybyte1;
@NoCereal uint nocereal1; //won't be serialised
@Bits!4 ubyte nibble;
@Bits!1 ubyte bit;
@Bits!3 ubyte bits3;
ubyte mybyte2; }
assert(MyStruct(3, 123, 14, 1, 42).cerealise == [ 3, 0xea /*1110
1 010*/, 42]);
mybyte1 = 3 ?
nocereal1 = 123 ?
nibble= 14 ?
bit = 1 ?
??? bits3 = ___ ???
mybyte2 = 42 ?
Re: write struct as raw data to file
Finished product... ~15k samples x 2 sin() waves/composite wave x 16 DTMF tones = 16 DTMF wave files in ~40ms! I love D.
Re: write struct as raw data to file
What's with the 4 bytes of zero? I miss-counted. All is well! Thanks Ali / Steven
Re: write struct as raw data to file
Hmm...well this is what I did and sort of got what I wanted; it
did compile and write data!
auto myStruct = new mystruct[1];
File f = File("myFile.wav", "wb");
f.rawWrite(myStruct); //this is 44 bytes
f.rawWrite(shortWaveArray);
What I got in the file was this:
-my 44 byte myStruct data + (4 bytes of zero)!
-then, my shortWaveArray data
What's with the 4 bytes of zero?
Thanks
write struct as raw data to file
I'm building a binary file. I can write my 'short[] myArray' directly to the file using: File f = File( "myFile.wav", "wb" ); f.rawWrite(myArray); It doesn't write any array formatting stuff (i.e. '[ , , ]'); it just moves the data into myFile like I want. I can't seem to do this with myStruct? myStruct is just a declaration and initialization of a dozen atomic types (e.g uint WAVE_Id = 0x45_56_41_57). When I issue f.rawWrite(myStruct), it writes "myStruct(...,...,etc. ) instead of just writing the data. Is there way to write the myStruct data to the file in a single statement...or two? Thanks for any assistance.
Re: associative array with element type struct ?
Of course! And it's very common. <= lol Thanks Ali. Much appreciated!
associative array with element type struct ?
Can I have an associative array with the element type being a
struct?
..this
26 // simple dual tone key struct
27 struct keytones { ushort rowFreq; ushort colFreq; }
28
29 // keypad associative array
30 keytones[string] keypad;
31 keypad["1"].rowFreq = 697; keypad["1"].colFreq = 1209;
...gets this response from DMD compiler
aaa.d(30): Error: undefined identifier `keypad`
aaa.d(30): Error: declaration `aaa.main.keytones` is already
defined
aaa.d(27):`struct` `keytones` is defined here
thanks for any assistance!
DMD32 D Compiler v2.097.2-dirty ?
I like to write CLEAN code:) Why does my DMD installation say v2.097.2-dirty?
Re: Assigning to class struct member leading to unexpected behavior.
On Thursday, 28 January 2021 at 02:03:40 UTC, Paul Backus wrote: The braced-initializer syntax only works in declarations, not assignments. Oh, I see, I'm guessing that explains the (sadly unfinished) In-place struct initialization DIP of wilzbach. (https://github.com/dlang/DIPs/pull/71) Kind of sad so many DIP's seem to end up stranded :/
Assigning to class struct member leading to unexpected behavior.
I'm experiencing a compile error, but for the life of me, I
cannot figure out what is wrong.
I'll try to keep it short but the code is roughly as follows:
class Window{
Screen screen;
alias screen this;
this() {
Screen s = {bottom_f: {[0, 1]}};
this.screen = s; // Works
this.screen = {bottom_f: {[0, 1]}}; // Leads to the
list of errors below
}
...
}
struct Screen{
Vec!(2, int) bottom_f;
...
}
alias Vec(uint size, Type) = Mat!(size, 1, Type);
struct Mat(uint rows, uint columns = rows, Type = float) {
private enum uint size = rows * columns;
union{
Type[columns][rows] mat;
Type[size] vec;
}
static if (columns == 1) alias vec this;
else alias mat this;
. . .
}
List of errors:
1. "Label "bottom_f" is not used."
2. "expected ; instead of }"
3. "found `}` when expecting `;` following statement"
4. "use `{ }` for an empty statement, not `;`"
5. "found `void` when expecting `;` following statement" (later
at function below constructor)
Why would assigning to a member variable lead to errors when
using an intermediate variable of the same type does not?
I tried tweaking a lot but I just can't figure it out. Am I doing
something wrong?
Re: Template argument deduction not working with template specialization
I just figured out half of my frustration is caused by a
collision between the 'alias this'd template possibillity and the
normal one.
For example:
struct Bar(uint size, V) {
V[size] blup;
alias blup this;
}
void foo(S : T[], T)(S a) {
pragma(msg, "first");
}
void foo(S : Bar!(T, U), uint T, U)(S a) {
pragma(msg, "second");
}
Bar!(2, int) bar;
foo(bar);
Will cause "called with argument types `(Bar!(2u, int))` matches
both:DUB"
(And "undefined identifier `T`DUB", "undefined identifier
`U`DUB", but thats a false positive :/)
While removal of either will make it work fine, as would removal
of the alias.
Templating:
The template picked to instantiate is the one that is most
specialized that fits the types of the TemplateArgumentList.
Alias this:
If an aggregate declaration defines an opCmp or opEquals
method, it will take precedence to that of the aliased this
member.
I was of the impression D only defaulted to the alias when the
original implementation of a (member) function was missing /
disfunctional. Shouldn't aliasing also follow this logic when
using template specializations? (Even though it may not be a
member function)
Re: Template argument deduction not working with template specialization
On Sunday, 17 January 2021 at 16:42:27 UTC, Steven Schveighoffer wrote: I've always hated that aspect of specialization. I don't really understand why it's valid (how can T be T[]?) I totally agree with that, that confuses me as well. This works: void TFoo(T : U[], U)(T a) Oh cool, that's surprising to say the least. Thanks! This indeed works with argument deduction :)
Template argument deduction not working with template specialization
While trying to use template specializations I noticed the
argument deductions do not yield the same version as the ones
yielded when being explicit.
Example:
uint a = 1;
uint[] b = [2];
TFoo(a);
TFoo!(uint[])(b);
void TFoo(T)(T a) {
pragma(msg, "T: " ~ T.stringof);
}
void TFoo(T : T[])(T[] a) {
pragma(msg, "T[]: " ~ T.stringof);
}
I noticed that an automatically deduced TFoo call always yields
the first, while TFoo!(uint[]) yields the array version if
present, and defaults to the first elsewise.
Am I incorrect in expecting the same behavior when (ab)using
argument deduction or does my usage make sense? I tried searching
for this combination (deduction & specialization) but couldn't
find another forum post / documentation example.
Re: Template alias as template specialisation not recognized.
On Saturday, 16 January 2021 at 01:38:38 UTC, Paul Backus wrote: You have encountered issue 1807: https://issues.dlang.org/show_bug.cgi?id=1807 Ah I see, thank you, sad to see several DIP's I'd be interested in are postponed :( Thanks for the workaround hint, I'll probably be using that.
Template alias as template specialisation not recognized.
I'm having issues when trying to use a template alias as a
template specialisation.
When using the following:
alias Vec(uint size, Type) = Mat!(size, 1, Type);
void setUniform(V : Vec!(L, bool), int L)(string name, V value)
{...}
Vec!(4, bool) a;
setUniform("test", a);
I get the following error:
template `shader.Shader.setUniform` cannot deduce function from
argument types `!()(string, Mat!(4u, 1u, bool))`, candidates
are:DUB
shader.d(43, 7): `setUniform(V : Vec!(L, bool), uint L)(string
name, V value)`
Meanwhile, when using the following, I have no issues:
void setUniform(V : Mat!(L, 1, bool), int L)(string name, V
value) {}
Re: opCast / operator overloading with additional template arguments
On Monday, 11 January 2021 at 00:48:49 UTC, Steven Schveighoffer
wrote:
I would think though, that this should work:
T opCast(T : Vec!(vecsize, S), S)()
Oh wouw, this seems to work perfectly! Awesome thanks ^^
Any Idea why
T opCast(T, S)() const if (is(T : Vec!(grootte, S))) {
yields the error
template instance opCast!(Vec!(2, double)) does not match
template declaration opCast(T, S)()
while your suggestion does not? It seems to me it should match
equally well.
Also I had no clue types inferred in constraints were
inaccessibly, I'll try to keep that in mind, though I wonder, is
there is any specific reason for that? Then again since your
example works inferred values shouldnt be necessary in
constraints anyway.
(On that note, is there per chance something like the underscore
'_' as in python? In some cases I don't care for all the template
arguments inside an is expression (with the (a:b, c) version))
Re: opCast / operator overloading with additional template arguments
On Monday, 11 January 2021 at 02:37:24 UTC, Ali Çehreli wrote:
>> T opCast(T)() const if (is(T : Vec!(size, S2), S2)) {
The is expression can be so complicated that I used a different
approach below.
if (isInstanceOfVec!T &&
T.init.content.length == size) {
// ADDED:
alias S2 = typeof(T.init.content[0]);
Is it ok to use .init even though we don't need an instantiated
value?
Re: opCast / operator overloading with additional template arguments
On Monday, 11 January 2021 at 00:25:36 UTC, Ali Çehreli wrote:
You don't show complete code; so, I hope I came up with
something that reflects your case.
Thank you, sadly S (S2 now) is not any specific type, sorry I'll
paste more of my file, I hope that's ok. (Sidenote, I'm not sure
it's the most elegant approach to have a templated union like
this, and I left out some unnecessary stuff like 'opBinary')
version (HoekjeD_Double) {
private alias standard_accuracy = double;
} else {
private alias standard_accuracy = float;
}
struct Vec(int size, S = standard_accuracy) {
union {
S[size] content;
static if (size >= 1) {
struct {
S x;
static if (size >= 2) {
S y;
static if (size >= 3) {
S z;
static if (size >= 4)
S w;
}
}
}
}
}
T opCast(T)() const if (is(T : Vec!(size, S2), S2)) {
T converted;
static foreach (i; 0 .. size)
converted.content[i] = cast(S2) content[i];
return converted;
}
}
opCast / operator overloading with additional template arguments
Is there a way to have additional template arguments in operator
overloads?
The problem I'm having is mostly caused by casting a templated
struct to other templated structs. I had the following code;
T opCast(T)() const if (is(T : Vec!(vecsize, S), S)) {
T converted;
static foreach (i; 0 .. vecsize)
converted.content[i] = cast(S) content[i];
return converted;
}
When I try to use this, I get the error 'undefined identifier S'.
Alternatively using:
T opCast(T, S)() . . .
causes the error 'template instance opCast!(Vec!(2, double)) does
not match template declaration opCast(T, S)()'
I found using 'alias S = typeof(content[0])' works as a kind of
ducttape alternative, however this seems like a codesmell to me,
and I fear it won't scale well either.
Am I missing a simple solution? And why is there no automatic
argument deduction in this scenario when compared to normal
function calls? (if the above opcast is translated to
'foo.opCast!T`)
Conflict when using stderr with import.
I'm trying to use stderr.writefln, while using the 'bindbc-opengl' package, but when I try to I get the message: source\app.d(13,2): Error: function std.stdio.makeGlobal!"core.stdc.stdio.stderr".makeGlobal at C:\D\dmd2\windows\bin\..\..\src\phobos\std\stdio.d(4853,20) conflicts with variable core.stdc.stdio.stderr at C:\D\dmd2\windows\bin\..\..\src\druntime\import\core\stdc\stdio.d(908,18) source\app.d(13,8): Error: template makeGlobal(StdFileHandle _iob)() does not have property writeln C:\D\dmd2\windows\bin\dmd.exe failed with exit code 1. This only happens when I import the 'bindbc.opengl' module I need, and importing less or being more specific also seems to leads to issues. Is there a way to prevent things like this / am I doing something wrong? Or is the issue more on the package's side? (In which case I may be asking at the wrong address)
Re: Tuple enumeration without integers or strings
On Sunday, 3 January 2021 at 06:05:48 UTC, frame wrote: The hash is also generated at compile time. Is there an easy way for me to know when code is assessed / generated at compile time? For example, is indexing a constant compile time array compile time or run time? Or how about functions? The hashOf documentation does not seem to hint to being done at compile time.
Re: Tuple enumeration without integers or strings
On Sunday, 3 January 2021 at 02:17:43 UTC, frame wrote:
Besides the problem with equal values, what's wrong with that:
alias Thing = Tuple!(int, int);
enum Wind {
A = Thing(0, 1),
B = Thing(0, 2),
C = Thing(0, 2)
}
void some_function(Wind w) {
switch (w.hashOf) {
case Wind.B.hashOf:
break;
default:
assert(0);
}
}
void main() {
some_function(Wind.B);
writefln("%d%d", Wind.C.expand);
}
I haven't used hashOf before, though assuming no equal values,
which I generally wouldn't do, I take it this is reliable? I
haven't tried it before, and I dont know how to effectively
compare it to using 'switch(w.to!string)' & 'case
Wind.B.stringof' (regarding speed/reliability).
Re: Tuple enumeration without integers or strings
On Saturday, 2 January 2021 at 21:48:04 UTC, Paul Backus wrote: Yes, but this will be true of any approach you choose. If two enum members have exactly the same value, there is no way to distinguish between them, either at compile time or at runtime. Oh I see, thanks! A bit of a bummer as I guess that means you're pretty much required to use an additional seperate structure like an array or map/associative array, the latter making the use of an enum instead of string names slightly pointless in this scenario, thank you nontheless .
Re: Tuple enumeration without integers or strings
On Saturday, 2 January 2021 at 03:20:29 UTC, Paul Backus wrote: D's switch statement only works on strings and integers. For more complex values, the easiest thing is to just use an if-else chain. If you really want to use a switch statement, you can do it by defining a function that maps each of your enum values to a unique integer; for example: Im afraid that would still result in issues when duplicate enum vlues are at play right? (This issue would maybe warrant a compile time warning imho)
Re: Tuple enumeration without integers or strings
It seems w.to!string works in conjunction with Wind.N.stringof,
though I wonder about the efficiency/wastefulness of this method.
Sadly this also leads to very funny behavior when some of the
enums have the same value, as to!string(Enum) will yield the name
of the first of these enums having the same values.
alias Thing = Tuple!(int, int);
enum Enum {
A = Thing(0, 1),
B = Thing(0, 2),
C = Thing(0, 2)
}
void main(){
Enum.C.to!string.writeln;
}
For example, the code above will print 'B' (I'm slightly curious
how & why std.conv uses the Enum name when converting to string,
instead of using the value, especially since I didn't see this
pitfall coming partly due to this)
So this neither seems a satisfiable solution to me :/
Re: New integer promotion rules
On Thursday, 18 January 2018 at 16:31:02 UTC, ag0aep6g wrote: I'm interpreting that to mean that it will become an error for some time, but later it will be allowed again with the new behavior. And then you can throw away `-transition=intpromote`. Seeing as it's almost 3 years later, I'd like to ask, is there an indication of when this will happen? It seems to still be around.
Re: Print int[string] sorted by Value
On Wednesday, 28 October 2020 at 15:27:04 UTC, H. S. Teoh wrote:
foreach (key; aa.keys.sort!((a,b) => aa[a] < aa[b])) {
writeln(key);
This solution worked perfectly without modifying any of my other
code. I don't fully understand it but can study up on the syntax.
Re: Print int[string] sorted by Value
On Wednesday, 28 October 2020 at 15:40:23 UTC, aberba wrote: Have you tries .values() function? dictionary.values.sort() Thanks aberba. Yes, that was my first attempt! If my terminology is correct that gives me a "range" of sorted VALUES. I think I can't "iterate"(foreach) through an array of VALUE[KEY] using the VALUE. I can only iterate over the KEYS...maybe? If my array is of type int[string] I can do: foreach(word-STRING, range-of-STRINGS) writeln(dictionary[word-STRING]); but not: foreach(value-INT, range-of-VALUES) writeln(dictionary[value-INT]<- wrong type);
Re: Print int[string] sorted by Value
On Wednesday, 28 October 2020 at 15:25:26 UTC, Paul Backus wrote:
auto sorted = dictionary.byPair.array.sort!((a, b) => a.value <
b.value)
It seems this method produces a ?sorted array of tuples?
[..Tuple!(string, "key", uint, "value")("Program", 74),
Tuple!(string, "key", uint, "value")("rd", 74)..]
I guess I would just have to iterate through the tuples.
Re: Print int[string] sorted by Value
Thanks Teoh
Re: Print int[string] sorted by Value
On Wednesday, 28 October 2020 at 15:25:26 UTC, Paul Backus wrote: On Wednesday, 28 October 2020 at 15:15:40 UTC, Paul wrote: per the D sample wc2.d size_t[string] dictionary; <-is printed by... . foreach (word1; dictionary.keys.sort) writef etc I want to print the dictionary sorted by value not key. I can write an algorithm but is there a library method(s) I can use to iterate through the array sorted by decreasing values? Thanks for your time. import std.array, std.algorithm; auto sorted = dictionary.byPair.array.sort!((a, b) => a.value < b.value) Thanks Paul
Print int[string] sorted by Value
per the D sample wc2.d size_t[string] dictionary; <-is printed by... . foreach (word1; dictionary.keys.sort) writef etc I want to print the dictionary sorted by value not key. I can write an algorithm but is there a library method(s) I can use to iterate through the array sorted by decreasing values? Thanks for your time.
Compile and run in Win10-VSCode
Hi Community, I'm Win10: I have VSCode installed. I have DMD installed and can compile examples from a Win CMD console. 1) How do I compile and run from within VSCode? 2) VSCode Extensions: Do I need them? One kept generating errors and a note said it was not under active development so I uninstalled it. The remaining two are by WebFreak. Are they working? Do I need them? Thanks for your time.
Re: Example uses "volatile"; compiler says "undefined identifier volatile"
Thank you. I'll try that.
Example uses "volatile"; compiler says "undefined identifier volatile"
I'm trying to build a Bare Bones 'OS' via example. Example says
to compile with
"gdc -c kernel.main.d -o kernel.main.o -g" I'm having trouble
getting GDC all set up..as I'm a rank amateur. So, I tried
compiling the example below with DMD. DMD spits out exceptions
to the use of 'volatile'. DIP62 on D wiki says status:REJECTED
for volatile.
Whats my work around here? This is what I'm trying to do->
https:// wiki.osdev.org / D_Bare_Bones
Thanks for any help.
module kernel.main;
extern(C) void main(uint magic, uint addr) {
int ypos = 0; //Starting points of the cursor
int xpos = 0;
const uint COLUMNS = 80; //Screensize
const uint LINES = 25;
ubyte* vidmem = cast(ubyte*)0x_8000_000B_8000; //Video
memory address
for (int i = 0; i < COLUMNS * LINES * 2; i++) { //Loops through
the screen and clears it
volatile *(vidmem + i) = 0;
}
volatile *(vidmem + (xpos + ypos * COLUMNS) * 2) = 'D' & 0xFF;
//Prints the letter D
volatile *(vidmem + (xpos + ypos * COLUMNS) * 2 + 1) = 0x07;
//Sets the colour for D to be light grey (0x07)
for (;;) { //Loop forever. You can add your kernel logic here
}
}
Re: Moving location of dub packages?
On Sunday, 21 July 2019 at 09:42:15 UTC, Andre Pany wrote: On Sunday, 21 July 2019 at 09:20:52 UTC, Andre Pany wrote: On Saturday, 20 July 2019 at 12:47:59 UTC, Paul wrote: I'd like to move where dub has stored packages to a shorter path, is there a procedure for this? Thanks in advance! Maybe the custom cache paths could help you here: https://dub.pm/settings.html Kind regards Andre Or you can set the environment variables before calling dub. The actual environment variables depends on your operation system. Please see here: https://github.com/dlang/dub/blob/master/source/dub/dub.d#L272 Kind regards Andre I don't think those options change where dub saves newly downloaded packages but it's good to know the options available. Thanks for the help! Paul
Moving location of dub packages?
I'd like to move where dub has stored packages to a shorter path, is there a procedure for this? Thanks in advance!
Re: Quotes inside wysiwyg strings, or alternative solution?
All string literals may span multiple lines. Ah, I didn't know that. Thanks for the detailed reply!
Quotes inside wysiwyg strings, or alternative solution?
Hi, I have searched, but can't find a solution. In C++ and Rust there is the option of enclosing a string in a sequence of chars (after R/r) to allow quotation marks in multiline string literals. What is the solution in D for wysiwyg strings (or similar) spanning multiple lines containing quotes and apostrophes? Thanks! (also, how can I put formatted code in a post?)
Re: How to concatenate a tuple of strings at compile time?
Thanks for the input. Unfortunately I still can't convince the compiler. __traits allMembers includes functions. Trying to filter those with std.traits.isCallable, it complains about strings that can't be read or fields that can't be accessed at compile time. Affected are both solutions. So any insight in why mixin(fullyQualifiedName!T ~ "." ~ item) produces a compiler error saying that string can't be accessed at compile time would be very appreciated. Same goes for [tuple(..)].filter!(item => !isCallable!(mixin(fullyQualifiedName!T ~ "." ~ item))).join;
How to concatenate a tuple of strings at compile time?
Hi!
How to concatenate a tuple of strings at compile time?
Appending to an enum or an immutable string in a static foreach
doesn't work. (And shadowing the thing doesn't work either) a)
Calling a function recursively doesn't work because I had to turn
the tuple into an array which cannot be read at compile time. b)
a)
enum/immutable string connected;
static foreach(item; __traits(something))
connected ~= item;
b)
string concat(string[] a, string b = "", index i = 0)
{
if (s.length - 1 == index)
{
return b ~ a[$-1];
} else {
return concat(a,b[index],index+1);
}
}
concat([__traits(something)]);
An internet search didn't reward any solution but probably I'm
just missing something very trivial.
Any clues would be very appreciated. Thanks.
On a different note, what I want to achieve is to automatically
generate a function call that hides the fact of a struct being
initialized.
something like this:
struct X
{
int a;
string b;
}
class C
{
X _x;
this(int a, string b)
{
_x = X(a, b);
}
}
Re: Initialise dynamic array in array of structures
On Tuesday, 21 June 2016 at 19:33:31 UTC, cym13 wrote:
... but “trackTemplates[0].coords = [{0, 9}, {1, 1},
{3, 6}];” is an assignment so the compiler can infer as much
and doesn't understand that each of those list of values are
really CoordLists.
I see, but it seems a bit strange given that they are being
assigned to .coords[] which is already defined as of type
CoordList.
trackTemplates[0].coords = [CoordList(0, 9), CoordList(1, 1),
CoordList(3, 6)];” would have worked as expected.
I'd want to avoid this wordy explicit way as the list can extend
to several hundred pairs. Most likely I need a better way to
store the information.
@ketmar:
Why is initialisation via {} bad (in simple terms please :D)? I
noticed while working on this bit of code that I could initialise
simple struct variables with {} but couldn't do the same with an
array of structs. I guess this is for the same or similar reason
to the above.
Thanks both for the help.
Initialise dynamic array in array of structures
Given these structures and declaration:
struct CoordList{
int x, y;
}
struct Part{
int x, y;
CoordList[] coords;
int nextNode, prevNode;
string nextEnter, prevEnter;
}
Part[10] trackTemplates;
Can someone please tell me why I can't initialise Part[0].coords
like this:
trackTemplates[0].coords = [ {0, 9}, {1, 1}, {3, 6} ];
but I can do this:
CoordList[] temp = [ {0, 9}, {1, 1}, {3, 6} ];
trackTemplates[0].coords = temp;
Many thanks!
Re: ref parameter qualifier and static arrays
On Wednesday, 9 September 2015 at 20:35:53 UTC, anonymous wrote: When you pass a slice (without ref), what's actually passed is a pointer and length. The contents are not copied. That means, when you alter an array element, the change will be done the original, even without ref: Thanks both. I see, temporary variable and no ref will do the job and I suppose it's better than just using a global...
ref parameter qualifier and static arrays
Is it possible to call a function like this... void foo(ref int[] anArray) ...with slices of static arrays? I thought I might be able to use [0..$-1] but to no avail - I get an error like this (which is confusing!): (ref int[] anArray) is not callable using argument types (int[]) I've modified the function declaration and used .ptr when calling it but it seems like a retrograde step for a modern language - although I suppose ref is pretty much the same thing. In practice I'm using arrays of structs (which are of various fixed sizes and known at compile time) that are currently global in scope - something that I'd like to avoid. I suppose I could just ask, what is the 'best' way to give access to variously sized static arrays between different modules?
Re: Superfluous code in switch statement
On Friday, 4 September 2015 at 21:20:11 UTC, Timon Gehr wrote:
On 09/04/2015 11:12 PM, anonymous wrote:
On Friday 04 September 2015 23:04, Timon Gehr wrote:
DMD never warns about dead code.
It warns here:
import std.stdio;
void main()
{
return;
writeln("hi"); /* Warning: statement is not reachable */
}
You are right, it does. Then I suppose there is no reason why
it shouldn't warn in the switch case.
I see, thanks.
Superfluous code in switch statement
I discovered the other day (during a cut and paste malfunction!)
that it's possible to have code before the first case in a
switch. Google tells me that it's legal C code and something I
read said it could be used for initialization but was rather
vague.
void main()
{
import std.stdio;
int a=1;
switch(a)
{
a=2;
writeln("hello");
case 1:
break;
case 2:
break;
default:
}
writeln(a);
}
The code before the 'case' has to be legal D code to pass
compilation but it seems to have no effect (which is probably a
good thing!). I was a bit surprised that the compiler (dmd)
didn't generate a warning when using the -w option.
Can someone explain what's going on here please?
Re: tkd - basic compilation problem
On Thursday, 2 July 2015 at 17:41:45 UTC, Gary Willoughby wrote: This is exactly why you use dub, so you don't have to worry about all this! You're right, there's sufficient information there if using dub.
Re: tkd - basic compilation problem
On Wednesday, 1 July 2015 at 09:38:05 UTC, Marc Schütz wrote: Someone more familiar with Debian/Ubuntu than me may be able to help you here, sorry. I was hoping to keep a tight rein on what was required to be installed to simplify deployment but its spiraling out of control again LOL. The -dev packages are only required during development (specifically at link time), the resulting binary only needs the normal packages installed. Thanks Marc, I found the required packages... it threw me because they don't have any version number in the repo ... and the example works just fine now.
Re: tkd - basic compilation problem
On Wednesday, 1 July 2015 at 17:43:11 UTC, Gary Willoughby wrote: On Tuesday, 30 June 2015 at 12:58:21 UTC, Paul wrote: ... I really don't understand posts like this when literally all information needed is in the README file: https://github.com/nomad-software/tkd Just read RTFM. I read that before posting, specifically the parts that say: Tkd requires version 8.6 (or greater) of the Tcl/Tk libraries installed. A small exception is when creating a self-contained installation on Windows. See details below. Tcl/Tk itself requires the x11 libraries installed on Linux only. and On Linux and Mac OSX things are a little easier as both operating systems have Tcl/Tk installed by default. If however they do not have the latest version, the libraries can be updated via their respective package managers. The linked libraries are libtcl and libtk. I can't see how they answer the questions I've asked (which admittedly are more related to the distro that D per se).
Re: tkd - basic compilation problem
On Wednesday, 1 July 2015 at 18:38:27 UTC, Jordi Sayol wrote: For shared linking against libphobos2.so and libtkd.so: $ dmd `pkg-config --cflags --libs tkd` -J/usr/share/libtkd-doc/example/media/ /usr/share/libtkd-doc/example/example.d For static linking against libphobos2.a and libtkd.a: $ dmd `pkg-config --cflags --libs tkd-static` -J/usr/share/libtkd-doc/example/media/ /usr/share/libtkd-doc/example/example.d Thank you Jordi, I've got everything installed ok now but those linking instructions might come in very handy!
Re: tkd - basic compilation problem
On Tuesday, 30 June 2015 at 16:06:41 UTC, Marc Schütz wrote: On Tuesday, 30 June 2015 at 15:25:27 UTC, Alex Parrill wrote: On Tuesday, 30 June 2015 at 14:28:49 UTC, Paul wrote: Using dub I get this during linking: Building tkd-test ~master configuration application, build type debug. Compiling using dmd... Linking... /usr/bin/ld: cannot find -ltcl /usr/bin/ld: cannot find -ltk ...any suggestions please? You need to install the libraries. Ex `sudo apt-get install libtcl8.5 libtk8.5` Or the corresponding -dev packages. Hmmm, I have libtcl8.6 and libtk8.6 installed already. The only dev packages I see are tclcl and tclap - I can't find any libtk -dev package. I was hoping to keep a tight rein on what was required to be installed to simplify deployment but its spiraling out of control again LOL.
Re: tkd - basic compilation problem
On Tuesday, 30 June 2015 at 13:22:43 UTC, Paul wrote: On Tuesday, 30 June 2015 at 13:19:25 UTC, Marc Schütz wrote: If you don't want to use DUB, you need to download the other two packages from code.dlang.org and specifiy -I/path/to/tcltk -I/path/to/x11 -I/path/to/tkd in the DMD invocation. Thank you, I'll try that. Added info: I wanted to avoid using dub so I could manually figure out what would be required to distribute the application.
Re: tkd - basic compilation problem
On Tuesday, 30 June 2015 at 13:19:25 UTC, Marc Schütz wrote: If you don't want to use DUB, you need to download the other two packages from code.dlang.org and specifiy -I/path/to/tcltk -I/path/to/x11 -I/path/to/tkd in the DMD invocation. Thank you, I'll try that.
