Re: A tutorial on D templates
On 13/01/12 10:48 PM, DNewbie wrote: I can't understand it. Why would someone need template programming. What problem does template solve? Well read on and see :-) Peter: Suppose you want to write a function to get the minimum of two integers. It's easy: Oh.. I see. Thank you everybody. And that's the first, more visible part of templates, a bit like generics in Java. Template are incomplete pieces of code with left-empty 'slots' which you can fill at compile-time to decide what code will be compiled. You can generate entire functions / class hierarchies or nicely crafted-for-your-need code / pre-computed-by-the-compiler code with templates. Philippe
Re: A tutorial on D templates
On Sat, Jan 14, 2012 at 01:08, Ali Çehreli acehr...@yahoo.com wrote: Here is another resource that tries to answer that question: http://ddili.org/ders/d.en/templates.html Parts of the source code may be left to the compiler to be filled in until that part is actually used in the program. Hi Ali, I discovered you had a chapter on templates just a few days ago. I'll go and read it. I think I'll add a ressources/further reading part in my doc and put a link to your chapter. Philippe
Re: A tutorial on D templates
On 01/14/2012 12:11 AM, Philippe Sigaud wrote: On Sat, Jan 14, 2012 at 01:08, Ali Çehreliacehr...@yahoo.com wrote: http://ddili.org/ders/d.en/templates.html Hi Ali, I discovered you had a chapter on templates just a few days ago. That chapter is intentionally incomplete. I think function, struct, and class templates and their uses with type template parameters are the most common. (That's a C++ programmer talking. ;)) I've left the rest of templates to a later chapter. I'll go and read it. Thank you. Please ignore the Inglish ;) mistakes for now. It is constantly being corrected by my editor (Ergin Güney) and I. I think I'll add a ressources/further reading part in my doc and put a link to your chapter. Thank you. I will do the same. It will be easier if it gets a permanent home, in addition to its github page ( https://github.com/PhilippeSigaud/D-templates-tutorial ). Philippe Ali
Re: A tutorial on D templates
On Sat, Jan 14, 2012 at 15:56, Ali Çehreli acehr...@yahoo.com wrote: On 01/14/2012 12:11 AM, Philippe Sigaud wrote: On Sat, Jan 14, 2012 at 01:08, Ali Çehreliacehr...@yahoo.com wrote: http://ddili.org/ders/d.en/templates.html Hi Ali, I discovered you had a chapter on templates just a few days ago. That chapter is intentionally incomplete. I think function, struct, and class templates and their uses with type template parameters are the most common. (That's a C++ programmer talking. ;)) I've left the rest of templates to a later chapter. I agree. Your goal is not exactly the same as mine: you intend to give a view on the entire language, for beginners, whereas I intend my doc to be a deep plunge into templates, as complete as possible. I'll go and read it. Thank you. Please ignore the Inglish ;) mistakes for now. It is constantly being corrected by my editor (Ergin Güney) and I. What I see is quite readable :-) I think I'll add a ressources/further reading part in my doc and put a link to your chapter. Thank you. I will do the same. That's cool, because the D community is small enough and still dispersed enough that we should link one another to bring it all together. It will be easier if it gets a permanent home, in addition to its github page ( https://github.com/PhilippeSigaud/D-templates-tutorial ). I have no permanent home for my D projects, nor do I intend to do. You can link to the Github project, that's what people do. Or directly to the pdf, if you wish.
Re: A tutorial on D templates
On Sat, Jan 14, 2012, at 09:07 AM, Philippe Sigaud wrote: On 13/01/12 10:48 PM, DNewbie wrote: I can't understand it. Why would someone need template programming. What problem does template solve? Well read on and see :-) Peter: Suppose you want to write a function to get the minimum of two integers. It's easy: Oh.. I see. Thank you everybody. And that's the first, more visible part of templates, a bit like generics in Java. Template are incomplete pieces of code with left-empty 'slots' which you can fill at compile-time to decide what code will be compiled. You can generate entire functions / class hierarchies or nicely crafted-for-your-need code / pre-computed-by-the-compiler code with templates. Philippe OK... I won't play with templates for now, but please keep up the good work.
Re: import std.c.windows.windows;
On Wed, Jan 11, 2012, at 01:16 PM, Mike Parker wrote: On 1/10/2012 10:57 PM, DNewbie wrote: On Tue, Jan 10, 2012, at 10:37 PM, Mike Parker wrote: Those samples use a binding to the Win32 API[1] that does not ship with DMD. So in your case, std.c.windows.windows is probably what you want for now. [1]http://dsource.org/projects/bindings/wiki/WindowsApi Ok.. I still don't understand why such a 'binding' is needed. Is std.c.windows.windows not enough for everyone? Unfortunately, no. It is not a complete binding of the Win32 API. It has a lot of stuff, but if you need more you need to look elsewhere. Andrej hit on some of the deficiencies in his post. Understood. I think I'll go with the binding. Thnk you.
Constant function/delegate literal
Hi,
Is there a reason why I cannot compile the following code:
module test;
struct Test {
int delegate(int) f;
}
Test s = Test((int x) { return x + 1; });
void main(string[] args) {
return;
}
dmd 2.057 says:
test.d(7): Error: non-constant expression cast(int delegate(int))delegate pure
nothrow @safe int(int x)
{
return x + 1;
}
?
This is simple example; what I want to do is to create a global variable
containing a structure with some ad-hoc defined functions. The compiler
complains that it cannot evaluate at compile time. I think this could
be solved by defining a function returning needed structure, but I think this
is cumbersome and inconvenient.
Best regards,
Vladimir Matveev.
Re: A tutorial on D templates
Good work Philippe, looks good!
Re: Absolute beginner
I've never noticed std.conv.parse takes a radix argument, silly me. And will take a look at readf from std.stream, definitely. Thanks! On 14 January 2012 01:20, Justin Whear jus...@economicmodeling.com wrote: On Fri, 13 Jan 2012 23:05:19 +0100, Matej Nanut wrote: While we're at it: what's the best way to parse in a formatted manner? For example, if I want to get 5 hexadecimal digits converted into an uint? And I want to simultaneously advance the string? sscanf seems fiddly and unsafe. Check out readf: http://d-programming-language.org/phobos/ std_stream.html#readf You'll need to wrap the string in a Stream interface (MemoryStream?), but since you're looking for advance-on-read, you want stream semantics anyhow. Justin
Re: Constant function/delegate literal
I guess these are CTFE (compile-time function evaluation) issues,
someone else might know more. A workaround is to use a module
constructor which will run before main():
struct Test {
int delegate(int) f;
}
Test s;
static this() {
s = Test((int x) { return x + 1; });
}
Note that 's' is thread-local, to make it shared across threads but
without implicit synchronization you can use:
__gshared Test s;
shared static this() {
s = Test((int x) { return x + 1; });
}
Note the use of *shared* in the module ctor. Without 'shared' it would
run every time a new thread was spawned.
Re: Fixed matrix rows joining
A rectangular array is really just one array, is it not? From a syntax
point it looks like a multidimensional array but really it's just a
single linear piece of memory, so just cast it:
void main()
{
int[2][4] table;
table[0][] = 0;
table[1][] = 1;
table[2][] = 2;
table[3][] = 3;
auto x = cast(int[])table;
assert(x == [0, 0, 1, 1, 2, 2, 3, 3]);
}
Re: Fixed matrix rows joining
I guess join() could be specialized for static arrays and then just do a dup and a cast? Would that work ok?
Re: std.algorithm.startsWith with maximal matching
On Fri, Jan 13, 2012 at 09:30:35PM -0800, Jonathan M Davis wrote: On Friday, January 13, 2012 18:47:19 H. S. Teoh wrote: [...] But what I really want to accomplish is to parse a string containing multiple words; at each point I have a list of permitted words that need to be matched against the string; substring matches don't count. I already have a way of skipping over spaces; so for medial words, I can simulate this by appending a space to the end of the word list passed to startsWith(). However, this doesn't work when the word being matched is at the very end of the string, or if it is followed by punctuation. Is there another library function that can do this, or do I just have to roll my own? Use std.array.split. It will split a string into an array of strings using whitespace as the delimiter. [...] What about punctuation? T -- Don't modify spaghetti code unless you can eat the consequences.
Re: std.algorithm.startsWith with maximal matching
On Saturday, January 14, 2012 19:13:02 H. S. Teoh wrote:
On Fri, Jan 13, 2012 at 09:30:35PM -0800, Jonathan M Davis wrote:
On Friday, January 13, 2012 18:47:19 H. S. Teoh wrote:
[...]
But what I really want to accomplish is to parse a string containing
multiple words; at each point I have a list of permitted words that
need to be matched against the string; substring matches don't
count. I already have a way of skipping over spaces; so for medial
words, I can simulate this by appending a space to the end of the
word list passed to startsWith(). However, this doesn't work when
the word being matched is at the very end of the string, or if it is
followed by punctuation.
Is there another library function that can do this, or do I just
have to roll my own?
Use std.array.split. It will split a string into an array of strings
using whitespace as the delimiter.
[...]
What about punctuation?
If you have to worry about punctuation, then == isn't going to work. You'll
need to use some other combination of functions to strip the punctuation from
one or both ends of the word. One possible solution would be something like
foreach(word; splitter!(std.uni.isWhite)(str))
{
auto found = find!(not!(std.uni.isPunctuation))(word);
if(found.startsWith(listOfWords))
{
//...
}
}
- Jonathan M Davis
Re: std.algorithm.startsWith with maximal matching
On Saturday, January 14, 2012 19:45:55 Jonathan M Davis wrote:
If you have to worry about punctuation, then == isn't going to work. You'll
need to use some other combination of functions to strip the punctuation
from one or both ends of the word. One possible solution would be something
like
foreach(word; splitter!(std.uni.isWhite)(str))
{
auto found = find!(not!(std.uni.isPunctuation))(word);
if(found.startsWith(listOfWords))
{
//...
}
}
Actually, if the word has to match exactly, then startsWith isn't going to cut
it. What you need to do is outright strip the punctuation from both ends.
You'd need something more like
word = find!(not!(std.uni.isPunctuation))(word);
word = array(until!(std.uni.isPunctuation)(word));
if(canFind(wordList, word))
{
//...
}
- Jonathan M Davis
