Re: Is this D or is it Javascript?
On Fri, Jul 5, 2013 at 5:21 AM, Adam D. Ruppe destructiona...@gmail.comwrote: [snip] d rox. !!! this is AWESOME! Now one can use a mix of static and dynamic typing which is really nice with document based databases. Being able to script subsections of a website is also really interesting. Nice bridge for javascript programmers to learn to use D. Just need a decent wrapper on phobos to fix the naming of some stuff.
Re: NDC Oslo talk: Generic Programming Galore Using D
On Thu, 04 Jul 2013 09:47:36 -0700, Andrei Alexandrescu wrote: Videos for my two NDC 2013 talks are now online. Generic Programming Galore using D at http://vimeo.com/68378925 and the HipHop Virtual Machine at http://vimeo.com/68383350. Andrei Reddit: http://www.reddit.com/r/programming/comments/1hp3bf/ generic_programming_galore_using_d_by_andrei/
Re: Is this D or is it Javascript?
There are many cases where you do not know in advance what type
of data is being received through an interface to some other
system. This happens with some databases, and with messaging
systems, and if you are interfacing to any dynamically or weakly
typed language, such as with js/json.
I will be looking at what you did closely, so thanks for sharing!
I'll also look at the interpreter, many uses for something like
that too.
Originally to solve these interfacing problems, I wrote a
property tree implementation in C++ that used a dynamically typed
variant similar to your var type. With a property tree, you can
dynamically generate any hierarchical structure to multiple and
varying depths, great to have when you have no idea what the
structures will look like in advance.
For the variant type, I added in protection for strong typing,
but it could be by-passed with automatic conversion (if possible)
between types. I used it to create a generalized API for sqlite
databases. Later on it was used for interfacing with messages
recvd/sent via json over tcp.
Later after deciding to switch to D, the first thing I did was to
re-write a similar property tree system in D, and the experience
was much better although with one notable exception: Unlike in
C++, I could not create conversion operators that infer the
receiving type when doing assignments from the variant, for
example:
int i;
char c;
i = var;
c = var;
in C++ the correct getter for returning int or char will be
called
eg
operator int(){...}
operator char(){...}
In D, I have to resort to something a manual system like this:
i = var.get!int;
c = var.get!char;
Not nearly as nice.
I suppose i could to this
c = var.get!(typeof(c));
Safer but very ugly and tedious.
My hope is if multiple alias ever arrives it will solve the
conversion issue. Do you have any insight on how to solve the
conversion problem using current D, and if you think multiple
alias this will solve the problem?
--rt
Re: Is this D or is it Javascript?
On Friday, 5 July 2013 at 22:51:57 UTC, Rob T wrote:
I suppose i could to this
c = var.get!(typeof(c));
Yeah, I did two things: int c = var.get!int; and
int c;
var v;
v.putInto(c);
[do] you think multiple alias this will solve the problem?
Maybe, but that would still be limited to a list of types. What
would be ideal is if alias this or opImplicitCast existed, or
implicit constructors like C++ has for function calls and
could be a template:
T get(T)() { ...}
alias get this;
int a = v; // rewrites to v.get!(int)
That won't work in all cases, there will be some where the type
requested is uncertain or ambiguous, but I'd say just go ahead
and error out there or pass the original var, if possible,
because this should cover most assignments.
But overall, I don't think the get!int is too bad. It is kinda
nice to know where you are transitioning back into static typed
world anyway.
BTW I'll push another commit to jsvar.d and script.d over the
weekend. I got return/break/continue working now (in the cases
I've tried at least, simple ones).
Re: Is this D or is it Javascript?
On 7/5/13 4:04 PM, Adam D. Ruppe wrote: BTW I'll push another commit to jsvar.d and script.d over the weekend. I got return/break/continue working now (in the cases I've tried at least, simple ones). I think you really should put the code in shape and convert your initial post into a blog entry. For a blog post at the level hmm, interesting I think you're already good to go. (An article would need more polishing.) I'd be glad to post it to reddit on Monday morning. Let me know. Andrei
Re: Is this D or is it Javascript?
On Friday, 5 July 2013 at 03:21:31 UTC, Adam D. Ruppe wrote: Is any of this useful for anything? idk, maybe parsing json or maybe the script language could find use. But the real point I'm trying to make here is simply that... d rox. Awesome work, and I think it's a nice code to study more about D too. PS: I just think that var is maybe too generic, I would called it as jsvar or anything like that, but this is just my opinion, anyway I liked your solution. Matheus.
Re: Is this D or is it Javascript?
On Friday, 5 July 2013 at 23:04:28 UTC, Adam D. Ruppe wrote:
Maybe, but that would still be limited to a list of types. What
would be ideal is if alias this or opImplicitCast existed, or
implicit constructors like C++ has for function calls and
could be a template:
T get(T)() { ...}
alias get this;
int a = v; // rewrites to v.get!(int)
Yes that would be much better.
What I always wanted to see, was full signature overloading
rather than only the partial signature overloading we currently
have.
eg
int get();
char get();
int a = get(); // calls int foo()
char b = get(); // calls char foo()
Technically there's no reason why this won't work. The cases
where there's ambiguity are virtually identical to what we
already experience with partial signature overloading. I have no
idea why this has not been seen as useful in most other
languages, it seems like a natural extension of the overloading
concept. I think only Haskel does something like it.
--rt
Re: Is this D or is it Javascript?
On Friday, 5 July 2013 at 08:26:23 UTC, Rory McGuire wrote:
Just need a decent wrapper on phobos to fix the naming of some
stuff.
That's fairly easy too:
import arsd.jsvar;
import arsd.script;
void main() {
var globals = var.emptyObject;
{
import std.algorithm;
var Math = globals.Math = var.emptyObject;
Math.max = std.algorithm.max!(var, var);
// testing it in D
import std.stdio;
// the second () is just because @property is
broken
writeln(Math.max()(12, 24)); // prints 24
}
{
import std.file;
var File = globals.File = var.emptyObject;
File.readText = readText!string;
}
import std.stdio;
writeln(interpret(Math.max(14, 33);, globals)); //
prints 33
writeln(interpret(File.readText(\test29.d\);,
globals)); // prints this file's source code
}
The opAssign function can wrap native functions pretty much
automatically. The one thing, as you can see here, is they do
need to be functions, not templates, so you might have to
instantiate them all with some type. But that's no big deal.
I don't remember if I mentioned this or not too, but the opAssign
and .get!T functions also can go to and from structs. Only the
data members, the methods won't work since the this pointer for
them would point to a var instead of the real type it expects,
but the data members and pulled/filled in by name, coercing types
as needed.
Anyway, if you did all these assignments, then you can make it
all available with dynamic calling from D or from the script
interpreter, without manually wrapping them.
It shouldn't be too hard to do a __traits(allMembers) over a
module too if you wanted to pull it all in at once, perhaps even
automatically instantiating the templates. But it would only work
especially well for free functions, again, due to the delegate
this problem. (Which I have an idea on how to solve - keep a copy
of the real type around, and update its pieces by way of a proxy
function that takes the name and searches for it, so the delegate
this/context pointer is still sane, but it was kinda buggy so I
dropped it. Another option would be to have other type tags
available, not just generic Type.Object, but something like
Type.NativeObject too that is added to the union. But meh, this
is pretty cool as it is imo.)
Re: Is this D or is it Javascript?
On Friday, 5 July 2013 at 23:58:30 UTC, Rob T wrote: What I always wanted to see, was full signature overloading rather than only the partial signature overloading we currently have. Indeed, that would be pretty cool.
Re: Is this D or is it Javascript?
On Friday, 5 July 2013 at 23:51:16 UTC, MattCoder wrote: PS: I just think that var is maybe too generic, I would called it as jsvar or anything like that, but this is just my opinion, anyway I liked your solution. I just wanted the authentic javascript experience :P You could also rename it with a selective import or something too.
Re: Is this D or is it Javascript?
On Friday, 5 July 2013 at 23:35:54 UTC, Andrei Alexandrescu wrote: I think you really should put the code in shape and convert your initial post into a blog entry. You know, I have a lot of things I want to blab about, but the problem is I don't have a blog! I'm slowly working on coding one (the off the shelf ones are universally awful imo) but it isn't high priority so... yeah. I really should either finish it or just give in and use a third party service or something (the closest I've come is this newsgroup!), since at least blog blabbing would be *some* documentation for half my random stuff, but just blargh, words cannot describe my hatred for WordPress and friends.
Re: Is this D or is it Javascript?
On Saturday, 6 July 2013 at 00:27:45 UTC, Adam D. Ruppe wrote: On Friday, 5 July 2013 at 23:35:54 UTC, Andrei Alexandrescu wrote: I think you really should put the code in shape and convert your initial post into a blog entry. You know, I have a lot of things I want to blab about, but the problem is I don't have a blog! I'm slowly working on coding one (the off the shelf ones are universally awful imo) but it isn't high priority so... yeah. I really should either finish it or just give in and use a third party service or something (the closest I've come is this newsgroup!), since at least blog blabbing would be *some* documentation for half my random stuff, but just blargh, words cannot describe my hatred for WordPress and friends. You could put something up on http://www.codeproject.com/
Re: Is this D or is it Javascript?
On 7/5/2013 5:27 PM, Adam D. Ruppe wrote: On Friday, 5 July 2013 at 23:35:54 UTC, Andrei Alexandrescu wrote: I think you really should put the code in shape and convert your initial post into a blog entry. You know, I have a lot of things I want to blab about, but the problem is I don't have a blog! I'm slowly working on coding one (the off the shelf ones are universally awful imo) but it isn't high priority so... yeah. I really should either finish it or just give in and use a third party service or something (the closest I've come is this newsgroup!), since at least blog blabbing would be *some* documentation for half my random stuff, but just blargh, words cannot describe my hatred for WordPress and friends. Just register adamruppe.com, and use Ddoc!
