"Try it now"

[Andrei Alexandrescu]

I'm quite excited about the new look of std (right now realized only by 
http://d-programming-language.org/phobos-prerelease/std_algorithm.html). 
Here's a suggestion on how we could improve it more.


Adam wrote an in-browser evaluator for D programs. These, when presented 
on the homepage with "hello, world" in them are of limited usefulness. 
However, a personalized "try it now" button present for _each_ artifact 
in an std module would be of great usefulness.


When I try some html or javascript I find it very useful to go to one of 
those sites that allow me to try some code right then and there. The key 
aspect is that the code edit field is already filled with code that is 
close to what I'm looking for, which I can then edit and try until it 
does what I want.


Similarly, it would be great if next to e.g. 
http://d-programming-language.org/phobos-prerelease/std_algorithm.html#setUnion 
there would be a "Try it now" button. Clicking on that button would open 
an overlay with an edit window. The edit window initially contains the 
example text:


unittest
{
  int[] a = [ 1, 2, 4, 5, 7, 9 ];
  int[] b = [ 0, 1, 2, 4, 7, 8 ];
  int[] c = [ 10 ];
  assert(setUnion(a, b).length == a.length + b.length);
  assert(equal(setUnion(a, b), [0, 1, 1, 2, 2, 4, 4, 5, 7, 7, 8, 9][]));
  assert(equal(setUnion(a, c, b), [0, 1, 1, 2, 2, 4, 4, 5, 7, 7, 8, 9, 
10][]));

}

Then the user can change, compile, and run that program, to ultimately 
close the overlay and return to the documentation.


What do you think? This would require some work in the compiler (make 
unittests documentable, make their text available to ddoc macros) and 
some work in the front end. I hope this catches the fancy of e.g. 
Walter/Don and Adam.



Andrei

Re: "Try it now"

[Adam D. Ruppe]

Andrei wrote:
> Adam wrote an in-browser evaluator for D programs. These, when
> presented on the homepage with "hello, world" in them are of
> limited usefulness.
> However, a personalized "try it now" button present for _each_
> artifact in an std module would be of great usefulness.

Indeed. I actually wrote a little javascript thing for that
new home page that's reusable across other ddoc or similar
sites. Check it out:

http://arsdnet.net/d-web-site/std_algorithm2.html

Every time it sees a d_code block, the script adds a button.
Hit the button, and you can edit the code and send it off
to my completelyexpendable vm to compile and run it.

(It's also on my not-quite-done newsreader so example code in
newsgroup posts are detected and made editable. That's less perfect
since it's trying to pick code out of unstructured text, but it
works reasonably well.)


Of course, most examples fail to actually compile... but maybe
a few replacement rules for the text - automatically insert main()
if it's not there, import std.all or similar at the top,
replace "..." with some generic data.

I think we could make the examples work with just a few lines of
code.


Unittests are a different story though, since their code isn't
in the HTML today. If dmd did make it available though, this same
script should work on it.

Re: "Try it now"

[Andrei Alexandrescu]

On 4/13/11 3:54 PM, Adam D. Ruppe wrote:

Andrei wrote:

Adam wrote an in-browser evaluator for D programs. These, when
presented on the homepage with "hello, world" in them are of
limited usefulness.
However, a personalized "try it now" button present for _each_
artifact in an std module would be of great usefulness.


Indeed. I actually wrote a little javascript thing for that
new home page that's reusable across other ddoc or similar
sites. Check it out:

http://arsdnet.net/d-web-site/std_algorithm2.html

Every time it sees a d_code block, the script adds a button.
Hit the button, and you can edit the code and send it off
to my completelyexpendable vm to compile and run it.

(It's also on my not-quite-done newsreader so example code in
newsgroup posts are detected and made editable. That's less perfect
since it's trying to pick code out of unstructured text, but it
works reasonably well.)


Of course, most examples fail to actually compile... but maybe
a few replacement rules for the text - automatically insert main()
if it's not there, import std.all or similar at the top,
replace "..." with some generic data.

I think we could make the examples work with just a few lines of
code.


Whoa, what a coincidence we were thinking along the same lines (never 
saw that).


To take this to pro level:

* Button shold be on the same like as "Example:" and spell "Try now". 
Maybe a more attractive shape/icon could help too.


* Once pressed, the subsequent edit should contain a "Cancel" that 
undoes the action.


* The compilation/running results should come in a nice inline 
variable-height stdout after the edit window, not in a new undecorated 
page. I wouldn't mind some "terminal" color scheme for that stdout with 
e.g. green on black letters or whatnot. Anyhow, the entire 
edit/compile/run flow should be very very smooth.


* Syntax highlighting in the editor :o)


Unittests are a different story though, since their code isn't
in the HTML today. If dmd did make it available though, this same
script should work on it.


Agreed. For now it would be terrific if you could take this proof of 
concept full course. I'll be waiting for your diff request!



Thanks,

Andrei

Re: "Try it now"

[bearophile]

Andrei:

> When I try some html or javascript I find it very useful to go to one of 
> those sites that allow me to try some code right then and there. The key 
> aspect is that the code edit field is already filled with code that is 
> close to what I'm looking for, which I can then edit and try until it 
> does what I want.

Time ago Walter said that online ways to try code snippets (like the ideone and 
codepad sites, and the Microsoft site to try Spec#) are no good. I am glad to 
see you don't agree :-) As you remember the Go site has a similar window even 
on the home page (JavaScript required): http://golang.org/


> What do you think?

I think this is a good idea that improves the usefulness of the (now active) 
documentation. In my opinion it's even going to produce more bug reports for 
DMD/Phobos.

Bye,
bearophile

Re: "Try it now"

[Andrei Alexandrescu]

On 4/13/11 4:26 PM, bearophile wrote:

Andrei:


When I try some html or javascript I find it very useful to go to one of
those sites that allow me to try some code right then and there. The key
aspect is that the code edit field is already filled with code that is
close to what I'm looking for, which I can then edit and try until it
does what I want.


Time ago Walter said that online ways to try code snippets (like the
ideone and codepad sites, and the Microsoft site to try Spec#) are no
good. I am glad to see you don't agree :-) As you remember the Go
site has a similar window even on the home page (JavaScript
required): http://golang.org/


I just wrote that examples the likes of golang.org are poor.

Andrei

Re: "Try it now"

[Matthias Pleh]

[..snip..]

Hey, that's so awesome, guys!
Keep up that work :)

°Matthias

Re: "Try it now"

[Andrej Mitrovic]

That is so awesome, great job Adam!

Now I *finally* have an excuse for those reports I made of examples
which don't compile (where the response was "nobody said examples
/have/ to compile, they're just demonstrations..").

Re: "Try it now"

[bearophile]

Adam D. Ruppe:

> * Since most of them don't actually output anything, the program
>   now detects output.length == 0 and says "Program run
>   successfully." upon completion to give some feedback.

This is a problem. Unittest code is not meant to produce an output, while 
online snippets to try are meant to nearly always produce a meaningful output.


> Hence, it's a little slow.

I agree, it's slow, and speeding it up a little will be an important 
improvement. But it's a nice page :-)


> Of course, if someone else
> has done it, I'm not above a little copy/paste action.

It may slow down editing even on modern browsers. I think it's not essential.

Bye,
bearophile

Re: "Try it now"

[Andrej Mitrovic]

It does alarm NoScript, which blocks it. It runs fine if I disable it
though, and probably most people don't use noscript.

Re: "Try it now"

[Adam D. Ruppe]

Andrej Mitrovic wrote:
> It does alarm NoScript, which blocks it.

Well, it *is* a script...

It would be possible to move the logic server side easily enough,
but I think the scripted interface is better anyway - no need to
show the output and edit windows at all times. The script allows
us to only show them when requested.

Re: "Try it now"

[Andrej Mitrovic]

I've always wondered.. how do you detect malicious D code? Or if
there's an infinite loop in the code? Or if the compiler suddenly
crashes? Or if the compilation takes so long that DMD exhausts all
memory? It seems like a dangerous thing to allow user code execution,
but I've no idea what goes behind the scenes..

Re: "Try it now"

[bearophile]

Adam D. Ruppe:

> Well, it *is* a script...
> 
> It would be possible to move the logic server side easily enough,
> but I think the scripted interface is better anyway - no need to
> show the output and edit windows at all times. The script allows
> us to only show them when requested.

Well designed user interfaces degrade gracefully. Here this means hiding the 
output and edit windows if JavaScript is enabled, and showing them if JS is not 
available on the user browser. I'd like the site to work without JS too.

Bye,
bearophile

Re: "Try it now"

[Adam D. Ruppe]

bearophile wrote:
> Well designed user interfaces degrade gracefully.

That's exactly why I took the approach I did... see below.

>  Here this means hiding the output and edit windows if JavaScript
> is enabled, and showing them if JS is not available on the user
> browser.

Showing has a cost. The site is easier to use without edit boxes
surrounding every example - it puts a lot of stuff in the way
of the content you're actually looking for; they get in the way.

While it's a cool little feature to have, it's not essential
to the site's main purpose, namely, presenting the documentation
in an easy to read fashion.

So the upsides of being fully functional (technically easy, btw,
the main thing is just a standard html form, and with the iframe
target, it'd do an inline submit without script too, no changes)
has to weighed against the downside of being cluttered.

With the script, it's possible to have the best of both worlds.
But, without the script, I just don't feel it's worth it. Toys
shouldn't get in the way of the main goal.

Re: "Try it now"

[Andrei Alexandrescu]

On 4/13/11 5:39 PM, Adam D. Ruppe wrote:

Andrei Alexandrescu wrote:

To take this to pro level:
* Button shold be on the same like as "Example:" and spell "Try
now". Maybe a more attractive shape/icon could help too.
* Once pressed, the subsequent edit should contain a "Cancel" that
undoes the action.
* The compilation/running results should come in a nice inline
variable-height stdout after the edit window



Got partially there. Can't spend too much time on this right now,
got some work projects that need to be finished by friday. I'm
pretty sure I can finish them in a day if I have to... but I don't
want to have to.

Anyway take a look. This is where I'll leave it until the weekend:

http://arsdnet.net/d-web-site/std_algorithm2.html


This is very close already! Two things if you get to work on this for 
the weekend:


* The console window should be of variable height (to fit the text) up 
to some number of rows (e.g. 40), and then scroll.


* The console window should be below, not above the edit window.

* The "Compile & Run" button should be "Run" to enhance the feeling of 
instant execution.


* The two buttons should be to the right of "Example:" (with some spacing)

* We need to go through all examples and make sure they are 
compilable... :o)


This is a great contribution, Adam. Thank you!


Andrei

Re: "Try it now"

[Andrei Alexandrescu]

On 4/13/11 6:11 PM, bearophile wrote:

Adam D. Ruppe:


* Since most of them don't actually output anything, the program
   now detects output.length == 0 and says "Program run
   successfully." upon completion to give some feedback.


This is a problem. Unittest code is not meant to produce an output, while 
online snippets to try are meant to nearly always produce a meaningful output.


I disagree. I find examples that use assert() much clearer than examples 
that print something to the console and then explain in a comment what 
you ought to be seeing.



Andrei

Re: "Try it now"

[bearophile]

Adam D. Ruppe:

> With the script, it's possible to have the best of both worlds.
> But, without the script, I just don't feel it's worth it. Toys
> shouldn't get in the way of the main goal.

Here's another idea:
1) detect if the user has active JS;
2) If the JS is active, then hide the in/out windows. If the JS is not active 
then hide everything, both windows and "try it" button, but add at the top of 
the window a link to an alternative page that's usable without JS that shows 
the in/out windows too.

Bye,
bearophile

Re: "Try it now"

[Adam D. Ruppe]

Andrej Mitrovic wrote:
> I've always wondered.. how do you detect malicious D code?

It doesn't. What it does is use the ulimit feature in linux to
limit the resources available to each process so they can't do
anything.

Try it:

int[] a;
a.length = 5_000_000; // "Memory allocation failed"


for(;;) {} // forcibly terminated by the kernel after ~8 seconds

auto f = File("cool_a_file", "wt");
for(int a = 0; a < 10_000; a++)
  f.writefln("%d", a);

// reports success, but the file is actually only 8 kb:

# ls -l cool_a_file
-rw-r--r-- 1 apache apache 8192 2011-04-13 19:22 cool_a_file

# tail -n 2 cool_a_file
1859
18 // you can see it got forcibly cut off

There's file permissions in place that you shouldn't be able to
access anything on there, except reading the system files. It's
a stock Linux install - nothing to see there. Writing is limited
to the scratchspace directory, which isn't public to the web or
anything.


What if you tried to fill the disk by creating files in a loop?
You actually can do that, until you're killed for either running
for too long or hitting the scratchspace's disk quota. I don't
know how to prevent that except for disabling files altogether,
and I think that would diminish the usefulness a little. File
examples are fun too.

(note if you do fill the scratchspace, it's not a big deal. It's
garbage collected in a way - the compile helper catches disk
full exceptions and cleans it out when needed. Still, don't do that.)

Access to the network is firewalled too. You can play on localhost
to a degree, but anything to and from the outside world is filtered.
Shouldn't be possible to run a spambot on it, since nothing on
that machine is allowed to call out, not even root.


Keep in mind that DMD lives under similar constraints. If it
goes wild, it will be killed by the kernel before too long too,
and can't make files bigger than about a megabyte. It's limited
to 256 MB of RAM.


This describes the limits in the operating system. There's
additional limits at the VM level, so even if you got root, you
couldn't do much with it. This is why it's also on a separate
domain name than anything else too - if you put a web exploit
on it, there's nothing much to do with that either. Like it's
name says, it's all completely expendable info.

Finally, I snapshotted the VM in a known good state. If you do
root the box, I can always revert to that too (considering writing
a program to automatically revert each day actually, but haven't
gotten around to it yet).

Of course, worst case scenario is I just pull the plug on it. I
hope it never comes to that, but some people are assholes, so
if I have to, it's an option.


Anyway, as you can see, I tried to cover all my bases with enough
fallback plans that I'm not concerned about malicious code at all.

Re: "Try it now"

[bearophile]

Andrei:

> I disagree. I find examples that use assert() much clearer than examples 
> that print something to the console and then explain in a comment what 
> you ought to be seeing.

I don't understand why you say that. Isn't learning and understanding based on 
feedback? If all the examples do is to show the same "assert passed" message, 
then what's the point in running the examples? Just reading a static page gives 
the same insight. You are able to modify them, of course, and see the modified 
asserts fail, and you may add a writeln statement yourself, but... having to 
modify each example to see some feedback is not a good default. I'd like to 
know if other people agree with you on this.

Bye,
bearophile

Re: "Try it now"

[Jonathan M Davis]

> On 4/13/11 6:11 PM, bearophile wrote:
> > Adam D. Ruppe:
> >> * Since most of them don't actually output anything, the program
> >> 
> >> now detects output.length == 0 and says "Program run
> >> successfully." upon completion to give some feedback.
> > 
> > This is a problem. Unittest code is not meant to produce an output, while
> > online snippets to try are meant to nearly always produce a meaningful
> > output.
> 
> I disagree. I find examples that use assert() much clearer than examples
> that print something to the console and then explain in a comment what
> you ought to be seeing.

I concur. The use of asserts in the examples is generally very clear. It also 
works great as a unit test, so if/when we make it so that ddoc examples are 
taken from unit test blocks, it works out really well. The example is both 
documented and tested. You can't do that with a print statement and a comment.

- Jonathan M Davis

Re: "Try it now"

[Walter Bright]

On 4/13/2011 1:54 PM, Adam D. Ruppe wrote:

Indeed. I actually wrote a little javascript thing for that
new home page that's reusable across other ddoc or similar
sites. Check it out:


I think what you've done is very innovative and cool!

Re: "Try it now"

[bearophile]

Adam D. Ruppe:

> Anyway, as you can see, I tried to cover all my bases with enough
> fallback plans that I'm not concerned about malicious code at all.

The author of codepad has a similar amount of healthy paranoia:
>Can you break it? You're welcome to try. Let me know if you have any success!<
http://codepad.org/about

Bye,
bearophile

Re: "Try it now"

[Adam D. Ruppe]

bearophile wrote:
> This is a problem. Unittest code is not meant to produce an output,
> while online snippets to try are meant to nearly always produce a
> meaningful output.

I don't know - I like the approach Andrei took in the docs, writing
a series of true assertations.

assert(sort([4, 2]) == [2, 4]);

does look pretty neat. I guess the alternative is:

writeln(sort[4, 2]); // prints "[2, 4]"

but it's not as compact with some examples and it doesn't quite
show the same thing - writeln's implementation could change things
there and those details are really beside the point of the example.

On the other hand, having output there might be more interesting
to look at than "yay the asserts all passed!".

I could go either way.


But, regardless, there's nothing much my compile helper and
javascript can do here. The examples in the documentation would
have to be changed.

> I agree, it's slow, and speeding it up a little will be an
> important improvement.

Yeah, I'd like to speed it up too, but I've gotta strike a balance
between being useful without being easily abused or expensive.
Right now, it has a separate VM, but still shares a physical
server with some of my other sites (otherwise I wouldn't be doing
this at all... dedicating a whole server to a free toy is too rich
for my blood).

I can't let it affect those other sites, so full speed isn't really
an option.

Re: "Try it now"

[Adam D. Ruppe]

bearophile wrote:
> If the JS is not active then hide everything, both windows and "try > it"
button, but add at the top of the page an alternative page

That could work. Links to little popups to try now could work too.

For this, we'll probably want to add it to my ddoc post-processor
(same program that adds my version of the cheat sheets and tables of
contents, automatically generated from text below).

It's not in use for dmd yet, nor may it ever be, but if so this
approach will work.

Re: "Try it now"

[Walter Bright]

On 4/13/2011 6:04 PM, Adam D. Ruppe wrote:

I don't know - I like the approach Andrei took in the docs, writing
a series of true assertations.

assert(sort([4, 2]) == [2, 4]);

does look pretty neat. I guess the alternative is:

writeln(sort[4, 2]); // prints "[2, 4]"

but it's not as compact with some examples and it doesn't quite
show the same thing - writeln's implementation could change things
there and those details are really beside the point of the example.

On the other hand, having output there might be more interesting
to look at than "yay the asserts all passed!".

I could go either way.


One advantage of the assert() approach is you won't have to over and over again 
add in the import std.stdio;


Not having any imports makes for a faster compile, too.

Re: "Try it now"

[Simen kjaeraas]

On Thu, 14 Apr 2011 01:11:48 +0200, bearophile   
wrote:



Adam D. Ruppe:


* Since most of them don't actually output anything, the program
  now detects output.length == 0 and says "Program run
  successfully." upon completion to give some feedback.


This is a problem. Unittest code is not meant to produce an output,  
while online snippets to try are meant to nearly always produce a  
meaningful output.


I thought about this - if D's reflection capabilities allowed it to
iterate over local variables, the system could simply add code to
print those, to the end of the unittest. Likely requires some
changes to the compiler, though.


--
Simen

Re: "Try it now"

[Daniel Gibson]

Am 14.04.2011 02:37, schrieb Andrei Alexandrescu:
> 
> * The "Compile & Run" button should be "Run" to enhance the feeling of
> instant execution.

Well D *is* a compiled language. Also this is an explanation for the
user why he doesn't get instant response (but has to wait two seconds or
something).

Cheer,
- Daniel

Re: "Try it now"

[Jacob Carlborg]

On 2011-04-13 22:38, Andrei Alexandrescu wrote:

I'm quite excited about the new look of std (right now realized only by
http://d-programming-language.org/phobos-prerelease/std_algorithm.html).
Here's a suggestion on how we could improve it more.

Adam wrote an in-browser evaluator for D programs. These, when presented
on the homepage with "hello, world" in them are of limited usefulness.
However, a personalized "try it now" button present for _each_ artifact
in an std module would be of great usefulness.

When I try some html or javascript I find it very useful to go to one of
those sites that allow me to try some code right then and there. The key
aspect is that the code edit field is already filled with code that is
close to what I'm looking for, which I can then edit and try until it
does what I want.

Similarly, it would be great if next to e.g.
http://d-programming-language.org/phobos-prerelease/std_algorithm.html#setUnion
there would be a "Try it now" button. Clicking on that button would open
an overlay with an edit window. The edit window initially contains the
example text:

unittest
{
int[] a = [ 1, 2, 4, 5, 7, 9 ];
int[] b = [ 0, 1, 2, 4, 7, 8 ];
int[] c = [ 10 ];
assert(setUnion(a, b).length == a.length + b.length);
assert(equal(setUnion(a, b), [0, 1, 1, 2, 2, 4, 4, 5, 7, 7, 8, 9][]));
assert(equal(setUnion(a, c, b), [0, 1, 1, 2, 2, 4, 4, 5, 7, 7, 8, 9,
10][]));
}

Then the user can change, compile, and run that program, to ultimately
close the overlay and return to the documentation.

What do you think? This would require some work in the compiler (make
unittests documentable, make their text available to ddoc macros) and
some work in the front end. I hope this catches the fancy of e.g.
Walter/Don and Adam.


Andrei


This is looking better and better each time. One thing I still don't 
like is the cheat sheet, I think it looks cluttered. I think it's just 
too much text in most of the rows. The text in the Set operations looks 
good.


I would also prefer more vertical space in some of the examples. I think 
the first example for the "reduce" function looks good but I find the 
example for the "filter" function harder to read because there's no 
empty newlines.


--
/Jacob Carlborg

Re: "Try it now"

[Sequ]

> bearophile wrote:
> > This is a problem. Unittest code is not meant to produce an output,
> > while online snippets to try are meant to nearly always produce a
> > meaningful output.
> ...

> assert(sort([4, 2]) == [2, 4]);
>
> does look pretty neat. I guess the alternative is:
>
> writeln(sort[4, 2]); // prints "[2, 4]"
> ...

> But, regardless, there's nothing much my compile helper and
> javascript can do here. The examples in the documentation would
> have to be changed.

Is it maybe possible for the Javascript to take all statements of the form:
assert(a == b);
and rewrite them (in the Source Code window that pops up) as:
writeln(a);
?
I'm sure something could be written that works for most of the code found
in the documentation (even if it doesn't work for all possible D code).

Re: "Try it now"

[spir]

On 04/13/2011 10:54 PM, Adam D. Ruppe wrote:

Andrei wrote:

Adam wrote an in-browser evaluator for D programs. These, when
presented on the homepage with "hello, world" in them are of
limited usefulness.
However, a personalized "try it now" button present for _each_
artifact in an std module would be of great usefulness.


Indeed. I actually wrote a little javascript thing for that
new home page that's reusable across other ddoc or similar
sites. Check it out:

http://arsdnet.net/d-web-site/std_algorithm2.html

Every time it sees a d_code block, the script adds a button.
Hit the button, and you can edit the code and send it off
to my completelyexpendable vm to compile and run it.

(It's also on my not-quite-done newsreader so example code in
newsgroup posts are detected and made editable. That's less perfect
since it's trying to pick code out of unstructured text, but it
works reasonably well.)


Of course, most examples fail to actually compile... but maybe
a few replacement rules for the text - automatically insert main()
if it's not there, import std.all or similar at the top,
replace "..." with some generic data.

I think we could make the examples work with just a few lines of
code.


Unittests are a different story though, since their code isn't
in the HTML today. If dmd did make it available though, this same
script should work on it.


What would be helpful, I guess, to have most examples work as is, is 
systematically:

* put the code in a unitest block
* add "void main () {}"
* "import std.commonimports;"
where commonimports is a to-be-defined module publicly importing common tools 
from std.* (there was a similar discussion about scripting in D):


public import std.stdio: write, writef, writeln, writefln;
public import std.string   : format, join;
public import std.conv : to;
...

Denis
--
_
vita es estrany
spir.wikidot.com

Re: "Try it now"

[spir]

On 04/14/2011 11:30 AM, Jacob Carlborg wrote:

On 2011-04-13 22:38, Andrei Alexandrescu wrote:

I'm quite excited about the new look of std (right now realized only by
http://d-programming-language.org/phobos-prerelease/std_algorithm.html).
Here's a suggestion on how we could improve it more.

Adam wrote an in-browser evaluator for D programs. These, when presented
on the homepage with "hello, world" in them are of limited usefulness.
However, a personalized "try it now" button present for _each_ artifact
in an std module would be of great usefulness.

When I try some html or javascript I find it very useful to go to one of
those sites that allow me to try some code right then and there. The key
aspect is that the code edit field is already filled with code that is
close to what I'm looking for, which I can then edit and try until it
does what I want.

Similarly, it would be great if next to e.g.
http://d-programming-language.org/phobos-prerelease/std_algorithm.html#setUnion
there would be a "Try it now" button. Clicking on that button would open
an overlay with an edit window. The edit window initially contains the
example text:

unittest
{
int[] a = [ 1, 2, 4, 5, 7, 9 ];
int[] b = [ 0, 1, 2, 4, 7, 8 ];
int[] c = [ 10 ];
assert(setUnion(a, b).length == a.length + b.length);
assert(equal(setUnion(a, b), [0, 1, 1, 2, 2, 4, 4, 5, 7, 7, 8, 9][]));
assert(equal(setUnion(a, c, b), [0, 1, 1, 2, 2, 4, 4, 5, 7, 7, 8, 9,
10][]));
}

Then the user can change, compile, and run that program, to ultimately
close the overlay and return to the documentation.

What do you think? This would require some work in the compiler (make
unittests documentable, make their text available to ddoc macros) and
some work in the front end. I hope this catches the fancy of e.g.
Walter/Don and Adam.


Andrei


This is looking better and better each time. One thing I still don't like is
the cheat sheet, I think it looks cluttered. I think it's just too much text in
most of the rows.


Agreed. May I suggest an easy (and imo sensible) doc guideline, which would 
also allow automatising cheat sheet generation?


1. The top line of each doc block defines the *purpose* of the given piece of 
code
   (meaning for a func either what value it computes, or what action it 
performs).
2. This line is taken as is by a cheat sheet generator.

Examples:

PI
  /** The value of pi.
  ... */

struct Circle
  /** Representation of a circle, as defined by radius & position of center.
  ... */

size_t indexOf (E elem) // method of some collection type
  /** Index of first occurrence of elem in collection --else throws IndexError.
  ... */

void_t erase (E elem)   // ditto
  /** Erase all occurrences of elem in collection.
  ... */

Denis
--
_
vita es estrany
spir.wikidot.com

Re: "Try it now"

[spir]

On 04/14/2011 01:11 AM, bearophile wrote:

* Since most of them don't actually output anything, the program
> now detects output.length == 0 and says "Program run
> successfully." upon completion to give some feedback.

This is a problem. Unittest code is not meant to produce an output, while 
online snippets to try are meant to nearly always produce a meaningful output.


All my unittest blocks produce meaningful output; there exist firstly for that. 
Am I an heretic?


Denis
--
_
vita es estrany
spir.wikidot.com

Re: "Try it now"

[spir]

On 04/14/2011 02:51 AM, Adam D. Ruppe wrote:

Andrej Mitrovic wrote:

I've always wondered.. how do you detect malicious D code?


It doesn't. What it does is use the ulimit feature in linux to
limit the resources available to each process so they can't do
anything.

Try it:

int[] a;
a.length = 5_000_000; // "Memory allocation failed"


for(;;) {} // forcibly terminated by the kernel after ~8 seconds

auto f = File("cool_a_file", "wt");
for(int a = 0; a<  10_000; a++)
   f.writefln("%d", a);

// reports success, but the file is actually only 8 kb:

# ls -l cool_a_file
-rw-r--r-- 1 apache apache 8192 2011-04-13 19:22 cool_a_file

# tail -n 2 cool_a_file
1859
18 // you can see it got forcibly cut off

There's file permissions in place that you shouldn't be able to
access anything on there, except reading the system files. It's
a stock Linux install - nothing to see there. Writing is limited
to the scratchspace directory, which isn't public to the web or
anything.


What if you tried to fill the disk by creating files in a loop?
You actually can do that, until you're killed for either running
for too long or hitting the scratchspace's disk quota. I don't
know how to prevent that except for disabling files altogether,
and I think that would diminish the usefulness a little. File
examples are fun too.

(note if you do fill the scratchspace, it's not a big deal. It's
garbage collected in a way - the compile helper catches disk
full exceptions and cleans it out when needed. Still, don't do that.)

Access to the network is firewalled too. You can play on localhost
to a degree, but anything to and from the outside world is filtered.
Shouldn't be possible to run a spambot on it, since nothing on
that machine is allowed to call out, not even root.


Keep in mind that DMD lives under similar constraints. If it
goes wild, it will be killed by the kernel before too long too,
and can't make files bigger than about a megabyte. It's limited
to 256 MB of RAM.


This describes the limits in the operating system. There's
additional limits at the VM level, so even if you got root, you
couldn't do much with it. This is why it's also on a separate
domain name than anything else too - if you put a web exploit
on it, there's nothing much to do with that either. Like it's
name says, it's all completely expendable info.

Finally, I snapshotted the VM in a known good state. If you do
root the box, I can always revert to that too (considering writing
a program to automatically revert each day actually, but haven't
gotten around to it yet).

Of course, worst case scenario is I just pull the plug on it. I
hope it never comes to that, but some people are assholes, so
if I have to, it's an option.


Anyway, as you can see, I tried to cover all my bases with enough
fallback plans that I'm not concerned about malicious code at all.


We'd need a sandbox.

Denis
--
_
vita es estrany
spir.wikidot.com

Re: "Try it now"

[spir]

On 04/14/2011 02:56 AM, bearophile wrote:

Andrei:


>  I disagree. I find examples that use assert() much clearer than examples
>  that print something to the console and then explain in a comment what
>  you ought to be seeing.

I don't understand why you say that. Isn't learning and understanding based on 
feedback?


Precisely ;-)
That's why sane unittest blocks may/should output! One needs proper data to 
study / diagnose / debig what code *actually* does.


Denis
--
_
vita es estrany
spir.wikidot.com

Re: "Try it now"

[spir]

On 04/14/2011 02:56 AM, bearophile wrote:

Andrei:


I disagree. I find examples that use assert() much clearer than examples
that print something to the console and then explain in a comment what
you ought to be seeing.


I don't understand why you say that. Isn't learning and understanding based on feedback? 
If all the examples do is to show the same "assert passed" message, then what's 
the point in running the examples? Just reading a static page gives the same insight. You 
are able to modify them, of course, and see the modified asserts fail, and you may add a 
writeln statement yourself, but... having to modify each example to see some feedback is 
not a good default. I'd like to know if other people agree with you on this.


I more or less agree with both of you. My problem with using asserts in code 
samples is:

* It's not a feature all languages have, thus readers may not know it (well).
* Asserts in sample is clever "highjacking" of a language feature for a clever 
side-effect.


The point of assert in true code is to catch a potential bug. The point of 
assert in sample code is to bring information to the reader, like if saying 
"this predicate holds here":

   assert(3/2 == 1);
Maybe an alias of assert for such use would help? (but I cannot find one) Or a 
simple comment would do the job better:

   // 3/2 == 1

I long for a different assert that would take one expression and a result, and 
writse out when 'assertMode' is 'verbose':

   assert(3/2, &);
   // outputs "3/2 : 1"
Then, we get both silent and verbose asserts in one go; the former for 
regression testing, the latter mode for diagnose or examples.


I currently do it that way:
auto n = 3/2;
writefln("3/2: %s, n); // commented out for regression test
assert(n == 1);

Denis
--
_
vita es estrany
spir.wikidot.com

Re: "Try it now"

[spir]

On 04/14/2011 03:04 AM, Adam D. Ruppe wrote:

bearophile wrote:

>  This is a problem. Unittest code is not meant to produce an output,
>  while online snippets to try are meant to nearly always produce a
>  meaningful output.

I don't know - I like the approach Andrei took in the docs, writing
a series of true assertations.

assert(sort([4, 2]) == [2, 4]);

does look pretty neat. I guess the alternative is:

writeln(sort[4, 2]); // prints "[2, 4]"


What about

   // sort([4, 2]) == [2, 4])

? Looks to me both simpler & clearer.

Denis
--
_
vita es estrany
spir.wikidot.com

Re: "Try it now"

[spir]

On 04/14/2011 06:32 AM, Walter Bright wrote:

On 4/13/2011 6:04 PM, Adam D. Ruppe wrote:

I don't know - I like the approach Andrei took in the docs, writing
a series of true assertations.

assert(sort([4, 2]) == [2, 4]);

does look pretty neat. I guess the alternative is:

writeln(sort[4, 2]); // prints "[2, 4]"

but it's not as compact with some examples and it doesn't quite
show the same thing - writeln's implementation could change things
there and those details are really beside the point of the example.

On the other hand, having output there might be more interesting
to look at than "yay the asserts all passed!".

I could go either way.


One advantage of the assert() approach is you won't have to over and over again
add in the import std.stdio;

Not having any imports makes for a faster compile, too.


... and helps in having safe sandboxes. This holds for simple comments as well:

assert(3/2 == 1);
vs
// 3/2 == 1

Denis
--
_
vita es estrany
spir.wikidot.com

Re: "Try it now"

[David Nadlinger]

On 4/14/11 2:26 PM, spir wrote:

Not having any imports makes for a faster compile, too.


... and helps in having safe sandboxes.


In which way exactly do I need an import to write »extern(C) int 
system(in char *); system(…);«?


David

Re: "Try it now"

[spir]

On 04/14/2011 02:40 PM, David Nadlinger wrote:

On 4/14/11 2:26 PM, spir wrote:

Not having any imports makes for a faster compile, too.


... and helps in having safe sandboxes.


In which way exactly do I need an import to write »extern(C) int system(in char
*); system(…);«?


Did I write "it provides safe sandboxes"?

Denis
--
_
vita es estrany
spir.wikidot.com

Re: "Try it now"

[David Nadlinger]

On 4/14/11 3:44 PM, spir wrote:

On 04/14/2011 02:40 PM, David Nadlinger wrote:

On 4/14/11 2:26 PM, spir wrote:

Not having any imports makes for a faster compile, too.


... and helps in having safe sandboxes.


In which way exactly do I need an import to write »extern(C) int
system(in char
*); system(…);«?


Did I write "it provides safe sandboxes"?

Denis


No, but you wrote that it »helps in having safe sandboxes«, and I'm 
curious how you think it would.


David

Re: "Try it now"

[Steven Schveighoffer]

On Wed, 13 Apr 2011 21:04:25 -0400, Adam D. Ruppe  
 wrote:



On the other hand, having output there might be more interesting
to look at than "yay the asserts all passed!".


I think this is a good point.  Someone playing with a language might type  
in the example, and do:


/home/steves> dmd example.d
/home/steves> ./example
/home/steves> (ok... I guess that worked, but I'm not sure what happened)

In other words, there is a benefit to the interaction with the learner.   
In other words, you get to "see it working", rather than only see when it  
fails.  You also get a confirmation that the compiler is actually building  
something.  For the above code, all one really knows is that the compiler  
made an executable.  There's no confirmation that the code being run is  
actually what you typed in.


Sometimes, I worry that my unit tests or asserts aren't running.  Every  
once in a while, I have to change one to fail to make sure that code is  
compiling (this is especially true when I'm doing version statements or  
templates).  It would be nice if there was a -assertprint mode which  
showed asserts actually running (only for the module compiled with that  
switch, of course).


-Steve

Re: "Try it now"

[David Nadlinger]

On 4/14/11 4:03 PM, Steven Schveighoffer wrote:

Sometimes, I worry that my unit tests or asserts aren't running. Every
once in a while, I have to change one to fail to make sure that code is
compiling (this is especially true when I'm doing version statements or
templates). It would be nice if there was a -assertprint mode which
showed asserts actually running (only for the module compiled with that
switch, of course).


You are not the only one, I can't resist to do this quite often when I 
work with template-heavy code, or compiler bugs come into play.


At least for the unit tests, this could probably be integrated with a 
test harness (and named tests), which would have a verbose mode which 
logs each completed unittest block.


David

Re: "Try it now"

[Andrei Alexandrescu]

On 4/14/11 6:52 AM, spir wrote:

On 04/14/2011 01:11 AM, bearophile wrote:

* Since most of them don't actually output anything, the program
> now detects output.length == 0 and says "Program run
> successfully." upon completion to give some feedback.

This is a problem. Unittest code is not meant to produce an output,
while online snippets to try are meant to nearly always produce a
meaningful output.


All my unittest blocks produce meaningful output; there exist firstly
for that. Am I an heretic?


No, you're just doing it wrong. Heretic might be sometimes good.

http://www.linfo.org/rule_of_silence.html

Andrei

Re: "Try it now"

[Andrei Alexandrescu]

On 4/14/11 6:49 AM, spir wrote:

On 04/14/2011 11:30 AM, Jacob Carlborg wrote:

On 2011-04-13 22:38, Andrei Alexandrescu wrote:

I'm quite excited about the new look of std (right now realized only by
http://d-programming-language.org/phobos-prerelease/std_algorithm.html).
Here's a suggestion on how we could improve it more.

Adam wrote an in-browser evaluator for D programs. These, when presented
on the homepage with "hello, world" in them are of limited usefulness.
However, a personalized "try it now" button present for _each_ artifact
in an std module would be of great usefulness.

When I try some html or javascript I find it very useful to go to one of
those sites that allow me to try some code right then and there. The key
aspect is that the code edit field is already filled with code that is
close to what I'm looking for, which I can then edit and try until it
does what I want.

Similarly, it would be great if next to e.g.
http://d-programming-language.org/phobos-prerelease/std_algorithm.html#setUnion

there would be a "Try it now" button. Clicking on that button would open
an overlay with an edit window. The edit window initially contains the
example text:

unittest
{
int[] a = [ 1, 2, 4, 5, 7, 9 ];
int[] b = [ 0, 1, 2, 4, 7, 8 ];
int[] c = [ 10 ];
assert(setUnion(a, b).length == a.length + b.length);
assert(equal(setUnion(a, b), [0, 1, 1, 2, 2, 4, 4, 5, 7, 7, 8, 9][]));
assert(equal(setUnion(a, c, b), [0, 1, 1, 2, 2, 4, 4, 5, 7, 7, 8, 9,
10][]));
}

Then the user can change, compile, and run that program, to ultimately
close the overlay and return to the documentation.

What do you think? This would require some work in the compiler (make
unittests documentable, make their text available to ddoc macros) and
some work in the front end. I hope this catches the fancy of e.g.
Walter/Don and Adam.


Andrei


This is looking better and better each time. One thing I still don't
like is
the cheat sheet, I think it looks cluttered. I think it's just too
much text in
most of the rows.


Agreed. May I suggest an easy (and imo sensible) doc guideline, which
would also allow automatising cheat sheet generation?

1. The top line of each doc block defines the *purpose* of the given
piece of code
(meaning for a func either what value it computes, or what action it
performs).
2. This line is taken as is by a cheat sheet generator.

Examples:

PI
/** The value of pi.
... */

struct Circle
/** Representation of a circle, as defined by radius & position of center.
... */

size_t indexOf (E elem) // method of some collection type
/** Index of first occurrence of elem in collection --else throws
IndexError.
... */

void_t erase (E elem) // ditto
/** Erase all occurrences of elem in collection.
... */

Denis


I prefer the cheat sheet contain code snippets. They are very terse and 
eloquent.


Andrei

Re: "Try it now"

[Andrei Alexandrescu]

On 4/14/11 7:25 AM, spir wrote:

On 04/14/2011 03:04 AM, Adam D. Ruppe wrote:

bearophile wrote:

> This is a problem. Unittest code is not meant to produce an output,
> while online snippets to try are meant to nearly always produce a
> meaningful output.

I don't know - I like the approach Andrei took in the docs, writing
a series of true assertations.

assert(sort([4, 2]) == [2, 4]);

does look pretty neat. I guess the alternative is:

writeln(sort[4, 2]); // prints "[2, 4]"


What about

// sort([4, 2]) == [2, 4])

? Looks to me both simpler & clearer.

Denis


I don't like that one bit. What is it trying to achieve or improve?

Andrei

Re: "Try it now"

[spir]

On 04/14/2011 04:21 PM, Andrei Alexandrescu wrote:

On 4/14/11 6:49 AM, spir wrote:

On 04/14/2011 11:30 AM, Jacob Carlborg wrote:

On 2011-04-13 22:38, Andrei Alexandrescu wrote:

I'm quite excited about the new look of std (right now realized only by
http://d-programming-language.org/phobos-prerelease/std_algorithm.html).
Here's a suggestion on how we could improve it more.

Adam wrote an in-browser evaluator for D programs. These, when presented
on the homepage with "hello, world" in them are of limited usefulness.
However, a personalized "try it now" button present for _each_ artifact
in an std module would be of great usefulness.

When I try some html or javascript I find it very useful to go to one of
those sites that allow me to try some code right then and there. The key
aspect is that the code edit field is already filled with code that is
close to what I'm looking for, which I can then edit and try until it
does what I want.

Similarly, it would be great if next to e.g.
http://d-programming-language.org/phobos-prerelease/std_algorithm.html#setUnion


there would be a "Try it now" button. Clicking on that button would open
an overlay with an edit window. The edit window initially contains the
example text:

unittest
{
int[] a = [ 1, 2, 4, 5, 7, 9 ];
int[] b = [ 0, 1, 2, 4, 7, 8 ];
int[] c = [ 10 ];
assert(setUnion(a, b).length == a.length + b.length);
assert(equal(setUnion(a, b), [0, 1, 1, 2, 2, 4, 4, 5, 7, 7, 8, 9][]));
assert(equal(setUnion(a, c, b), [0, 1, 1, 2, 2, 4, 4, 5, 7, 7, 8, 9,
10][]));
}

Then the user can change, compile, and run that program, to ultimately
close the overlay and return to the documentation.

What do you think? This would require some work in the compiler (make
unittests documentable, make their text available to ddoc macros) and
some work in the front end. I hope this catches the fancy of e.g.
Walter/Don and Adam.


Andrei


This is looking better and better each time. One thing I still don't
like is
the cheat sheet, I think it looks cluttered. I think it's just too
much text in
most of the rows.


Agreed. May I suggest an easy (and imo sensible) doc guideline, which
would also allow automatising cheat sheet generation?

1. The top line of each doc block defines the *purpose* of the given
piece of code
(meaning for a func either what value it computes, or what action it
performs).
2. This line is taken as is by a cheat sheet generator.

Examples:

PI
/** The value of pi.
... */

struct Circle
/** Representation of a circle, as defined by radius & position of center.
... */

size_t indexOf (E elem) // method of some collection type
/** Index of first occurrence of elem in collection --else throws
IndexError.
... */

void_t erase (E elem) // ditto
/** Erase all occurrences of elem in collection.
... */

Denis


I prefer the cheat sheet contain code snippets. They are very terse and 
eloquent.

Andrei


Right. Sounds sensible.

Denis
--
_
vita es estrany
spir.wikidot.com

Re: "Try it now"

[spir]

On 04/14/2011 03:50 PM, David Nadlinger wrote:

On 4/14/11 3:44 PM, spir wrote:

On 04/14/2011 02:40 PM, David Nadlinger wrote:

On 4/14/11 2:26 PM, spir wrote:

Not having any imports makes for a faster compile, too.


... and helps in having safe sandboxes.


In which way exactly do I need an import to write »extern(C) int
system(in char
*); system(…);«?


Did I write "it provides safe sandboxes"?

Denis


No, but you wrote that it »helps in having safe sandboxes«, and I'm curious how
you think it would.


I mean imports usually bring in many more tools for naughty code. And I guess 
in some languages, naughty actions can only be performed via such imported 
modules (system control, direct memory access,...), thus forbidding import is 
an easy way of creating a sandbox. At the very minimum, forbidding import or 
limiting it to a predefined set of modules is a necessary first step, I guess.


Denis
--
_
vita es estrany
spir.wikidot.com

Re: "Try it now"

[Andrej Mitrovic]

If you remove asserts then we're forced to run the examples every time
we want to remind ourselves of what the code does. With assert it's
obvious what the code does.

And besides, why discourage newbies from learning about assert?
Looking at examples with write's could make them think it's a standard
way of debugging code. "Just print all the values, and then check them
one by one to see that they're valid". Let them learn about asserts
and unittests.

Another thing is that I believe most newcomers to D are C/C++
programmers. If we show them how easy it is to check code for
validity, they might start thinking that using asserts and unittests
isn't such a bad thing after all. If you ask an average C++ programmer
whether they use asserts and unittests they'll probably say "No,
because it's too difficult to set up and run them, and I'm too lazy".
Heck, every other day someone comes up with a brand new unittest C++
_library_, and people are completely uninterested.

IMO we shouldn't be hiding D's top features just because they might
look foreign at first.

Re: "Try it now"

[spir]

On 04/14/2011 04:22 PM, Andrei Alexandrescu wrote:

On 4/14/11 6:52 AM, spir wrote:

On 04/14/2011 01:11 AM, bearophile wrote:

* Since most of them don't actually output anything, the program
> now detects output.length == 0 and says "Program run
> successfully." upon completion to give some feedback.

This is a problem. Unittest code is not meant to produce an output,
while online snippets to try are meant to nearly always produce a
meaningful output.


All my unittest blocks produce meaningful output; there exist firstly
for that. Am I an heretic?


No, you're just doing it wrong. Heretic might be sometimes good.

http://www.linfo.org/rule_of_silence.html


Right, I know that and totally disagree. This rule is IMO the exact opposite of 
human-friendliness (numerous authors on usability and friends share this 
opinion, indeed).
Also, this is not what I'm talking about: I'm not here expecting just "all 
fine, brother", but various data helping me and understand how things actually 
worked; to be short, data useful to the coder during development or debug. See 
also reply to Steven's post.


Denis
--
_
vita es estrany
spir.wikidot.com

Re: "Try it now"

[Daniel Gibson]

Am 14.04.2011 16:56, schrieb spir:
> On 04/14/2011 03:50 PM, David Nadlinger wrote:
>> On 4/14/11 3:44 PM, spir wrote:
>>> On 04/14/2011 02:40 PM, David Nadlinger wrote:
 On 4/14/11 2:26 PM, spir wrote:
>> Not having any imports makes for a faster compile, too.
>
> ... and helps in having safe sandboxes.

 In which way exactly do I need an import to write »extern(C) int
 system(in char
 *); system(…);«?
>>>
>>> Did I write "it provides safe sandboxes"?
>>>
>>> Denis
>>
>> No, but you wrote that it »helps in having safe sandboxes«, and I'm
>> curious how
>> you think it would.
> 
> I mean imports usually bring in many more tools for naughty code. And I
> guess in some languages, naughty actions can only be performed via such
> imported modules (system control, direct memory access,...), thus
> forbidding import is an easy way of creating a sandbox. At the very
> minimum, forbidding import or limiting it to a predefined set of modules
> is a necessary first step, I guess.
> 
> Denis

As long as any C function can be called just by defining it, this is
just snake oil. For other languages this may work, but it'd make more
sense to just use a modified standard-lib that asserts when forbidden
functions are used.

For D (and probably any other system programming language) it makes more
sense to restrict on OS level, for example with SELinux, and assume that
the user code is pure evil.

Cheers,
- Daniel

Re: "Try it now"

[spir]

On 04/14/2011 04:24 PM, Andrei Alexandrescu wrote:

On 4/14/11 7:25 AM, spir wrote:

On 04/14/2011 03:04 AM, Adam D. Ruppe wrote:

bearophile wrote:

> This is a problem. Unittest code is not meant to produce an output,
> while online snippets to try are meant to nearly always produce a
> meaningful output.

I don't know - I like the approach Andrei took in the docs, writing
a series of true assertations.

assert(sort([4, 2]) == [2, 4]);

does look pretty neat. I guess the alternative is:

writeln(sort[4, 2]); // prints "[2, 4]"


What about

// sort([4, 2]) == [2, 4])

? Looks to me both simpler & clearer.

Denis


I don't like that one bit. What is it trying to achieve or improve?


assert(sort([4, 2]) == [2, 4]);

What is it trying to achieve or improve?
plus: is this bebug code / error catching; or information to the reader?

Denis
--
_
vita es estrany
spir.wikidot.com

Re: "Try it now"

[Andrei Alexandrescu]

On 4/14/11 9:03 AM, Steven Schveighoffer wrote:

Sometimes, I worry that my unit tests or asserts aren't running. Every
once in a while, I have to change one to fail to make sure that code is
compiling (this is especially true when I'm doing version statements or
templates). It would be nice if there was a -assertprint mode which
showed asserts actually running (only for the module compiled with that
switch, of course).


Could this be achieved within the language?

Andrei

Re: "Try it now"

[Steven Schveighoffer]

On Thu, 14 Apr 2011 12:48:26 -0400, Andrei Alexandrescu  
 wrote:



On 4/14/11 9:03 AM, Steven Schveighoffer wrote:

Sometimes, I worry that my unit tests or asserts aren't running. Every
once in a while, I have to change one to fail to make sure that code is
compiling (this is especially true when I'm doing version statements or
templates). It would be nice if there was a -assertprint mode which
showed asserts actually running (only for the module compiled with that
switch, of course).


Could this be achieved within the language?


I think you need to do it at the compiler level to make it useful.  For  
example, an assert like:


assert(container.length == 5);

To print this out properly, I'd want to see that the assert passed, but  
also what the test was.  I think there is already some work being  
commissioned (if not already in progress) on dissecting the expression  
into string form in the compiler.


I don't know how you would do this in a DRY fashion without compiler  
help.  You can't use a mixin string because mixins are compiled in the  
context where you mix them in.


I outlined a possible solution in a response to Daniel that I believe:

1. allows one to 'see' an example working that just uses asserts
2. allows one to run specific unit tests to make sure they are working  
(via names)

3. does not require any changes to any asserts in existance.

I think this would be an awesome feature.  One of the cool things about  
the new way phobos runs unit tests (one module at a time) is that if a  
particular test fails, I can just build/run it over and over again until  
it passes.  This is huge since to run the full phobos unit tests can take  
a while.


To just be able to select on the command line how to run unit tests (I  
think overtaking the command line args for unittest-enabled code is  
reasonable) would be a great tool for debugging code via unittests and  
assert printouts.


It also gives us a smooth transition into using ddoc examples as unit  
tests.


-Steve

Re: "Try it now"

[Andrei Alexandrescu]

On 4/14/11 10:34 AM, spir wrote:

On 04/14/2011 04:22 PM, Andrei Alexandrescu wrote:

On 4/14/11 6:52 AM, spir wrote:

On 04/14/2011 01:11 AM, bearophile wrote:

* Since most of them don't actually output anything, the program
> now detects output.length == 0 and says "Program run
> successfully." upon completion to give some feedback.

This is a problem. Unittest code is not meant to produce an output,
while online snippets to try are meant to nearly always produce a
meaningful output.


All my unittest blocks produce meaningful output; there exist firstly
for that. Am I an heretic?


No, you're just doing it wrong. Heretic might be sometimes good.

http://www.linfo.org/rule_of_silence.html


Right, I know that and totally disagree.


This is a good cue to revisit your opinion.


This rule is IMO the exact
opposite of human-friendliness (numerous authors on usability and
friends share this opinion, indeed).


This may be a misunderstanding of a valid human friendliness concern 
with a simple mistake. In addition, you reject an authoritative text 
with an appeal to an undefined authority.


Applying "let me output something and eye it" at the level of each unit 
test does not scale because it makes it extremely difficult to identify 
issues once one test of many produces unexpected output. There are 
programs (such as "expect") that automate that task. The ultimate goal 
is to make errors noisy and easy to identify.



Also, this is not what I'm talking about: I'm not here expecting just
"all fine, brother", but various data helping me and understand how
things actually worked; to be short, data useful to the coder during
development or debug. See also reply to Steven's post.


I understand, and I repeat: that approach works great for exploration, 
but won't scale for systematic unit testing.



Andrei

Re: "Try it now"

[Jonathan M Davis]

> On 04/14/2011 04:22 PM, Andrei Alexandrescu wrote:
> > On 4/14/11 6:52 AM, spir wrote:
> >> On 04/14/2011 01:11 AM, bearophile wrote:
>  * Since most of them don't actually output anything, the program
>  
>  > now detects output.length == 0 and says "Program run
>  > successfully." upon completion to give some feedback.
> >>> 
> >>> This is a problem. Unittest code is not meant to produce an output,
> >>> while online snippets to try are meant to nearly always produce a
> >>> meaningful output.
> >> 
> >> All my unittest blocks produce meaningful output; there exist firstly
> >> for that. Am I an heretic?
> > 
> > No, you're just doing it wrong. Heretic might be sometimes good.
> > 
> > http://www.linfo.org/rule_of_silence.html
> 
> Right, I know that and totally disagree. This rule is IMO the exact
> opposite of human-friendliness (numerous authors on usability and friends
> share this opinion, indeed).
> Also, this is not what I'm talking about: I'm not here expecting just "all
> fine, brother", but various data helping me and understand how things
> actually worked; to be short, data useful to the coder during development
> or debug. See also reply to Steven's post.

And I have no clue what you'd want to print. Normally, if the assertion 
passes, everything's fine. Seeing output from it would just be noise. Now, 
being able to verify that a particular unit test block is running when you're 
dealing with version blocks could be useful periodically, but all you really 
need to verify is that the test is run, not what it's doing. If you need to 
debug it, you debug it. And if you need to debug it, usually the assertions 
would be failing anyway. Having debug output printing all of the time would 
just get in the way and make it harder to find what you need when you're 
actually debugging, since you'd have too much debug output if everything's 
printing debug output. So, I really don't understand what you'd be looking to 
print.

I can understand someone wanting the list of tests printed so that they could 
see where in the tests the program is, but generally, all you need to know is 
whether the tests failed, and seeing the failed assertions gives you that. So, 
ultimately, I don't really understand the push for stuff being printed during 
unit tests unless you're explicitly debugging a unit test.

- Jonathan M Davis

Re: "Try it now"

[Andrei Alexandrescu]

On 4/14/11 12:00 PM, Steven Schveighoffer wrote:

On Thu, 14 Apr 2011 12:48:26 -0400, Andrei Alexandrescu
 wrote:


On 4/14/11 9:03 AM, Steven Schveighoffer wrote:

Sometimes, I worry that my unit tests or asserts aren't running. Every
once in a while, I have to change one to fail to make sure that code is
compiling (this is especially true when I'm doing version statements or
templates). It would be nice if there was a -assertprint mode which
showed asserts actually running (only for the module compiled with that
switch, of course).


Could this be achieved within the language?


I think you need to do it at the compiler level to make it useful. For
example, an assert like:

assert(container.length == 5);

To print this out properly, I'd want to see that the assert passed, but
also what the test was.


What's needed here is a "text of expression" feature similar to C's "#". 
That would help enforce and other artifacts too. I'm thinking along the 
lines of:


void myassert(string expr = __traits(text, condition))(bool condition) {
  ...
}

with, of course, a simpler syntax.


I think this would be an awesome feature. One of the cool things about
the new way phobos runs unit tests (one module at a time) is that if a
particular test fails, I can just build/run it over and over again until
it passes. This is huge since to run the full phobos unit tests can take
a while.


That's exactly how Phobos unittest work on Linux, and that was the 
motivation behind making it work that way.



Andrei

Re: "Try it now"

[Steven Schveighoffer]

On Thu, 14 Apr 2011 13:16:33 -0400, Andrei Alexandrescu  
 wrote:



On 4/14/11 12:00 PM, Steven Schveighoffer wrote:

On Thu, 14 Apr 2011 12:48:26 -0400, Andrei Alexandrescu
 wrote:


On 4/14/11 9:03 AM, Steven Schveighoffer wrote:

Sometimes, I worry that my unit tests or asserts aren't running. Every
once in a while, I have to change one to fail to make sure that code  
is
compiling (this is especially true when I'm doing version statements  
or

templates). It would be nice if there was a -assertprint mode which
showed asserts actually running (only for the module compiled with  
that

switch, of course).


Could this be achieved within the language?


I think you need to do it at the compiler level to make it useful. For
example, an assert like:

assert(container.length == 5);

To print this out properly, I'd want to see that the assert passed, but
also what the test was.


What's needed here is a "text of expression" feature similar to C's "#".  
That would help enforce and other artifacts too. I'm thinking along the  
lines of:


void myassert(string expr = __traits(text, condition))(bool condition) {
   ...
}

with, of course, a simpler syntax.


It still isn't exactly right.  Assert has some special properties that  
cannot be duplicated exactly with library code.  Such as true lazy  
evaluation and elimination during release mode.


But yes, it would be nice to be able to get a string of the parameters of  
a function (macro?).  It would certainly make this more feasible.


However, all this is ignoring one simple thing -- the hundreds of  
thousands of lines of code (mostly from std.datetime ;) ) that already  
have asserts.  Hooking assert directly automatically gives us a tool for  
printf debugging without changing any code.


I would point out that even for this solution, we are still modifying the  
compiler.  Any particular reason why adding a new trait is more desirable  
than modifying assert?  I certainly feel that the auto-inclusion of all  
the existing asserts would far outweigh the extensibility of adding a  
trait (which could probably also be added at the same time).





I think this would be an awesome feature. One of the cool things about
the new way phobos runs unit tests (one module at a time) is that if a
particular test fails, I can just build/run it over and over again until
it passes. This is huge since to run the full phobos unit tests can take
a while.


That's exactly how Phobos unittest work on Linux, and that was the  
motivation behind making it work that way.


Yeah, I know, that's why I brought it up :)

-Steve

Re: "Try it now"

[Jonathan M Davis]

> On Thu, 14 Apr 2011 13:16:33 -0400, Andrei Alexandrescu
> 
>  wrote:
> > On 4/14/11 12:00 PM, Steven Schveighoffer wrote:
> >> On Thu, 14 Apr 2011 12:48:26 -0400, Andrei Alexandrescu
> >> 
> >>  wrote:
> >>> On 4/14/11 9:03 AM, Steven Schveighoffer wrote:
>  Sometimes, I worry that my unit tests or asserts aren't running. Every
>  once in a while, I have to change one to fail to make sure that code
>  is
>  compiling (this is especially true when I'm doing version statements
>  or
>  templates). It would be nice if there was a -assertprint mode which
>  showed asserts actually running (only for the module compiled with
>  that
>  switch, of course).
> >>> 
> >>> Could this be achieved within the language?
> >> 
> >> I think you need to do it at the compiler level to make it useful. For
> >> example, an assert like:
> >> 
> >> assert(container.length == 5);
> >> 
> >> To print this out properly, I'd want to see that the assert passed, but
> >> also what the test was.
> > 
> > What's needed here is a "text of expression" feature similar to C's "#".
> > That would help enforce and other artifacts too. I'm thinking along the
> > lines of:
> > 
> > void myassert(string expr = __traits(text, condition))(bool condition) {
> > 
> > ...
> > 
> > }
> > 
> > with, of course, a simpler syntax.
> 
> It still isn't exactly right. Assert has some special properties that
> cannot be duplicated exactly with library code. Such as true lazy
> evaluation and elimination during release mode.
> 
> But yes, it would be nice to be able to get a string of the parameters of
> a function (macro?). It would certainly make this more feasible.
> 
> However, all this is ignoring one simple thing -- the hundreds of
> thousands of lines of code (mostly from std.datetime ;) ) that already
> have asserts. Hooking assert directly automatically gives us a tool for
> printf debugging without changing any code.

Actually, std.datetime doesn't use assert much. It mostly uses a version of 
assertPred which it has as a private function. Also, I've been rewriting the 
unit tests, and that will result in far fewer actual lines with assert or 
_assertPred thanks to more looping and whatnot. It does increase the need for 
printing out the actual results from an assertion though (which _assertPred 
does on failure). And what you're asking for here is at least related to the 
requested improvements to assert which resulted in assertPred being scrapped.

- Jonathan M Davis

Re: "Try it now"

[Steven Schveighoffer]

On Thu, 14 Apr 2011 13:38:11 -0400, Jonathan M Davis   
wrote:


Actually, std.datetime doesn't use assert much. It mostly uses a version  
of
assertPred which it has as a private function. Also, I've been rewriting  
the

unit tests, and that will result in far fewer actual lines with assert or
_assertPred thanks to more looping and whatnot. It does increase the  
need for
printing out the actual results from an assertion though (which  
_assertPred
does on failure). And what you're asking for here is at least related to  
the
requested improvements to assert which resulted in assertPred being  
scrapped.


I forgot that assert isn't actually used much in std.datetime!

-Steve

Re: "Try it now"

[Andrei Alexandrescu]

On 4/14/11 12:26 PM, Steven Schveighoffer wrote:

Any particular reason why adding a new trait is more
desirable than modifying assert?


Absolutely!

Andrei

Re: "Try it now"

[Steven Schveighoffer]

On Thu, 14 Apr 2011 13:54:00 -0400, Andrei Alexandrescu  
 wrote:



On 4/14/11 12:26 PM, Steven Schveighoffer wrote:

Any particular reason why adding a new trait is more
desirable than modifying assert?


Absolutely!


Maybe I worded my question wrong.  What I meant was what *is* the  
particular reason.


And keep in mind, when I say modifying assert, I mean changing the way  
assert compiles, not changing it's usage.


-Steve

Re: "Try it now"

[Andrei Alexandrescu]

On 4/14/11 1:26 PM, Steven Schveighoffer wrote:

On Thu, 14 Apr 2011 13:54:00 -0400, Andrei Alexandrescu
 wrote:


On 4/14/11 12:26 PM, Steven Schveighoffer wrote:

Any particular reason why adding a new trait is more
desirable than modifying assert?


Absolutely!


Maybe I worded my question wrong. What I meant was what *is* the
particular reason.


Already mentioned it - enforce() is a prime example. Any similar 
facility could make good use the feature.



And keep in mind, when I say modifying assert, I mean changing the way
assert compiles, not changing it's usage.


I understand.


Andrei

Re: "Try it now"

[spir]

On 04/14/2011 07:09 PM, Andrei Alexandrescu wrote:

Applying "let me output something and eye it" at the level of each unit test
does not scale because it makes it extremely difficult to identify issues once
one test of many produces unexpected output. There are programs (such as
"expect") that automate that task. The ultimate goal is to make errors noisy
and easy to identify.


I do agree. But this point gets very different once:
(1) One can selectively chose which tests to run, thus having only output from 
one(s) relevant to the issue at hand (eg via named unittests),

(2) one can switch from silent to verbose modes.

In the case of unittests used for regression testing (*), the silent mode would 
initially just say "there is an error here". Then switching to verbose mode, on 
relevant tests only, would provide helpful data to solve the issue.
But for me unittests are far to be useful only for regression tests. They are 
everyday development tools I constantly use: as sample code, to study what code 
actually does, te debud or improve a piece of code; even if I don't practice 
TDD at all (rarely use tests as kinf of spec).


I have talked about that already, but the message seems difficult to pass for a 
reason I do not grok.


Denis

(*) I mean, to check all still works fine after a change on an initially 
running codebase.

--
_
vita es estrany
spir.wikidot.com

Re: "Try it now"

[Steven Schveighoffer]

On Thu, 14 Apr 2011 14:57:44 -0400, Andrei Alexandrescu  
 wrote:



On 4/14/11 1:26 PM, Steven Schveighoffer wrote:

On Thu, 14 Apr 2011 13:54:00 -0400, Andrei Alexandrescu
 wrote:


On 4/14/11 12:26 PM, Steven Schveighoffer wrote:

Any particular reason why adding a new trait is more
desirable than modifying assert?


Absolutely!


Maybe I worded my question wrong. What I meant was what *is* the
particular reason.


Already mentioned it - enforce() is a prime example. Any similar  
facility could make good use the feature.


Sure.  However, not modifying assert means all asserts in my code should  
now be rewritten to myassert, or whatever function is implemented.  The  
huge benefit of modifying assert is that we don't have to change any  
existing code.


I'm not saying adding a trait is not desirable, I just think it doesn't  
get us to the right place on its own.


If I ever get around to hacking the compiler, I certainly will try this to  
see how well it works.


-Steve

Re: "Try it now"

[Gerrit Wichert]

Am 13.04.2011 22:38, schrieb Andrei Alexandrescu:
I'm quite excited about the new look of std (right now realized only 
by 
http://d-programming-language.org/phobos-prerelease/std_algorithm.html). 


I just had a look and stumbled over the short description of group:

 
group([5, 2, 2, 3, 3]) returns a range containing the tuples 
tuple(5, 1), tuple(5, 1), tuple(2, 2), and tuple(3, 2).


there seems to be one 'touple(5, 1)' too much.

Re: "Try it now"

[David Nadlinger]

On 4/14/11 9:38 PM, Gerrit Wichert wrote:

Am 13.04.2011 22:38, schrieb Andrei Alexandrescu:

I'm quite excited about the new look of std (right now realized only
by
http://d-programming-language.org/phobos-prerelease/std_algorithm.html).


I just had a look and stumbled over the short description of group:


group([5, 2, 2, 3, 3]) returns a range containing the tuples tuple(5,
1), tuple(5, 1), tuple(2, 2), and tuple(3, 2).

there seems to be one 'touple(5, 1)' too much.


This is already fixed in Git, but Andrei apparently didn't get around to 
update the build on the website – thanks anyway.


David

Re: "Try it now"

[spir]

On 04/14/2011 09:10 PM, Steven Schveighoffer wrote:

On Thu, 14 Apr 2011 14:57:44 -0400, Andrei Alexandrescu
 wrote:


On 4/14/11 1:26 PM, Steven Schveighoffer wrote:

On Thu, 14 Apr 2011 13:54:00 -0400, Andrei Alexandrescu
 wrote:


On 4/14/11 12:26 PM, Steven Schveighoffer wrote:

Any particular reason why adding a new trait is more
desirable than modifying assert?


Absolutely!


Maybe I worded my question wrong. What I meant was what *is* the
particular reason.


Already mentioned it - enforce() is a prime example. Any similar facility
could make good use the feature.


Sure. However, not modifying assert means all asserts in my code should now be
rewritten to myassert, or whatever function is implemented. The huge benefit of
modifying assert is that we don't have to change any existing code.

I'm not saying adding a trait is not desirable, I just think it doesn't get us
to the right place on its own.

If I ever get around to hacking the compiler, I certainly will try this to see
how well it works.


A solution may be to carefully craft the new trait-using func's interface so 
that upgrading can be automatised (rewriting tool for assert calls only); 
possibly with constraints to make the tool's life easier, like "assertions 
stands alone on their line".


Denis
--
_
vita es estrany
spir.wikidot.com

Re: "Try it now"

[Andrei Alexandrescu]

On 4/14/11 3:00 PM, David Nadlinger wrote:

On 4/14/11 9:38 PM, Gerrit Wichert wrote:

Am 13.04.2011 22:38, schrieb Andrei Alexandrescu:

I'm quite excited about the new look of std (right now realized only
by
http://d-programming-language.org/phobos-prerelease/std_algorithm.html).


I just had a look and stumbled over the short description of group:



group([5, 2, 2, 3, 3]) returns a range containing the tuples tuple(5,
1), tuple(5, 1), tuple(2, 2), and tuple(3, 2).

there seems to be one 'touple(5, 1)' too much.


This is already fixed in Git, but Andrei apparently didn't get around to
update the build on the website – thanks anyway.

David


BTW there is a proposal to change group to yield a range of ranges 
instead of a range of tuples.


Do you folks estimate this could cause significant harm to existing code?


Thanks,

Andrei

Re: "Try it now"

[bearophile]

Andrei:

> BTW there is a proposal to change group to yield a range of ranges 
> instead of a range of tuples.
> 
> Do you folks estimate this could cause significant harm to existing code?

This proposal makes group closer to the semantics of the Python 
itertools.groupby. This change doesn't harm my code significantly.

But in my Python code most times I use groupby I have to convert the inner 
generator (the inner range) in something eager. So for me the current behaviour 
of group is OK. What are the reasons to change it?

Bye,
bearophile

Re: "Try it now"

[Andrei Alexandrescu]

On 4/14/11 3:31 PM, bearophile wrote:

Andrei:


BTW there is a proposal to change group to yield a range of ranges
instead of a range of tuples.

Do you folks estimate this could cause significant harm to existing code?


This proposal makes group closer to the semantics of the Python 
itertools.groupby. This change doesn't harm my code significantly.

But in my Python code most times I use groupby I have to convert the inner 
generator (the inner range) in something eager. So for me the current behaviour 
of group is OK. What are the reasons to change it?

Bye,
bearophile


The reasons for changing is that often you have groups in which elements 
are not identical, but instead in the same equivalence class. So you 
want not only their number - you want to take a look at the actual 
items. (Consider e.g. grouping some strings by their length.)


Andrei

Re: "Try it now"

[Jacob Carlborg]

On 2011-04-14 16:03, Steven Schveighoffer wrote:

On Wed, 13 Apr 2011 21:04:25 -0400, Adam D. Ruppe
 wrote:


On the other hand, having output there might be more interesting
to look at than "yay the asserts all passed!".


I think this is a good point. Someone playing with a language might type
in the example, and do:

/home/steves> dmd example.d
/home/steves> ./example
/home/steves> (ok... I guess that worked, but I'm not sure what happened)

In other words, there is a benefit to the interaction with the learner.
In other words, you get to "see it working", rather than only see when
it fails. You also get a confirmation that the compiler is actually
building something. For the above code, all one really knows is that the
compiler made an executable. There's no confirmation that the code being
run is actually what you typed in.

Sometimes, I worry that my unit tests or asserts aren't running. Every
once in a while, I have to change one to fail to make sure that code is
compiling (this is especially true when I'm doing version statements or
templates). It would be nice if there was a -assertprint mode which
showed asserts actually running (only for the module compiled with that
switch, of course).

-Steve


I agree. For one of my projects I created a simple unit test "framework" 
that:


* Displays the number of tests
* Doesn't stop the whole run when a single assert fails
* Prints out the failing asserts, if any
* It's possible to add descriptions to the tests

The testing framework in use: 
http://www.dsource.org/projects/orange/browser/tests/Serializer.d#L249


The actual framework: 
http://www.dsource.org/projects/orange/browser/orange/test/UnitTester.d


--
/Jacob Carlborg

Re: "Try it now"

[Jacob Carlborg]

On 2011-04-14 18:48, Andrei Alexandrescu wrote:

On 4/14/11 9:03 AM, Steven Schveighoffer wrote:

Sometimes, I worry that my unit tests or asserts aren't running. Every
once in a while, I have to change one to fail to make sure that code is
compiling (this is especially true when I'm doing version statements or
templates). It would be nice if there was a -assertprint mode which
showed asserts actually running (only for the module compiled with that
switch, of course).


Could this be achieved within the language?

Andrei


Don't know exactly how he wants it to behave but I have have a look one 
of my earlier posts:


http://www.digitalmars.com/pnews/read.php?server=news.digitalmars.com&group=digitalmars.D&artnum=134796

--
/Jacob Carlborg

Re: "Try it now"

[Roman Ivanov]

== Quote from Jacob Carlborg (d...@me.com)'s article
> On 2011-04-14 18:48, Andrei Alexandrescu wrote:
> > On 4/14/11 9:03 AM, Steven Schveighoffer wrote:
> >> Sometimes, I worry that my unit tests or asserts aren't running. Every
> >> once in a while, I have to change one to fail to make sure that code is
> >> compiling (this is especially true when I'm doing version statements or
> >> templates). It would be nice if there was a -assertprint mode which
> >> showed asserts actually running (only for the module compiled with that
> >> switch, of course).
> >
> > Could this be achieved within the language?
> >
> > Andrei
> Don't know exactly how he wants it to behave but I have have a look one
> of my earlier posts:
>
http://www.digitalmars.com/pnews/read.php?server=news.digitalmars.com&group=digitalmars.D&artnum=134796

I'm somewhat shifting the topic, but it seems strange that unit tests are run 
when
you run an executable. Wouldn't it make sense to run them immediately after
compilation? I mean, what would be the use case where you would want to re-run a
unit test on the code that's already compiled and tested? This could also solve
the problem with messages on success, since you can output a success message 
after
compilation.

Sorry if I'm missing some obvious issue with this suggestion.

Re: "Try it now"

[Jonathan M Davis]

> == Quote from Jacob Carlborg (d...@me.com)'s article
> 
> > On 2011-04-14 18:48, Andrei Alexandrescu wrote:
> > > On 4/14/11 9:03 AM, Steven Schveighoffer wrote:
> > >> Sometimes, I worry that my unit tests or asserts aren't running. Every
> > >> once in a while, I have to change one to fail to make sure that code
> > >> is compiling (this is especially true when I'm doing version
> > >> statements or templates). It would be nice if there was a
> > >> -assertprint mode which showed asserts actually running (only for the
> > >> module compiled with that switch, of course).
> > > 
> > > Could this be achieved within the language?
> > > 
> > > Andrei
> > 
> > Don't know exactly how he wants it to behave but I have have a look one
> 
> > of my earlier posts:
> http://www.digitalmars.com/pnews/read.php?server=news.digitalmars.com&group
> =digitalmars.D&artnum=134796
> 
> I'm somewhat shifting the topic, but it seems strange that unit tests are
> run when you run an executable. Wouldn't it make sense to run them
> immediately after compilation? I mean, what would be the use case where
> you would want to re-run a unit test on the code that's already compiled
> and tested? This could also solve the problem with messages on success,
> since you can output a success message after compilation.
> 
> Sorry if I'm missing some obvious issue with this suggestion.

You essentially need an executable to run the unit tests. It doesn't 
technically have to be an altered version of the normal executable, but you 
need an executable. It was probably just simplest to alter the normal 
executable so that it included the unit tests. Code coverage works the same 
way. Also, it could be desirable to build the unit tests without actually 
running them, at least some of the time, so separating the unit test build 
from actually running the unit tests can be beneficial.

Regardless, the way it works works quite well overall. What is typically done, 
I believe is create a module with an empty main specifically for running the 
unit tests. So, building with -unittest isn't usually done with the normal 
executable, and you don't typically run your normal executable with the unit 
tests included in it.

And as for the lack of messages on success, the whole idea is that there be no 
messages on success. You don't normally care about the unit tests unless they 
fail, so messages on success are just useless cruft in most cases, and it's 
_much_ easier to verify that the unit tests past programmatically if the 
output on success is nothing. Besides, if you really want to output success 
for each unit test, all you have to do is add writeln calls to the end of all 
your tests (annoying perhaps, but not hard). It would certainly be possible to 
add a flag to dmd that made it so that each test printed out on success for 
those who wanted it, but the value is questionable, and Walter and the other 
compiler devs have much more critical issues to work on.

- Jonathan M Davis

Re: "Try it now"

[Jérôme M. Berger]

Roman Ivanov wrote:
> == Quote from Jacob Carlborg (d...@me.com)'s article
>> On 2011-04-14 18:48, Andrei Alexandrescu wrote:
>>> On 4/14/11 9:03 AM, Steven Schveighoffer wrote:
 Sometimes, I worry that my unit tests or asserts aren't running. Every
 once in a while, I have to change one to fail to make sure that code is
 compiling (this is especially true when I'm doing version statements or
 templates). It would be nice if there was a -assertprint mode which
 showed asserts actually running (only for the module compiled with that
 switch, of course).
>>> Could this be achieved within the language?
>>>
>>> Andrei
>> Don't know exactly how he wants it to behave but I have have a look one
>> of my earlier posts:
>>
> http://www.digitalmars.com/pnews/read.php?server=news.digitalmars.com&group=digitalmars.D&artnum=134796
> 
> I'm somewhat shifting the topic, but it seems strange that unit tests are run 
> when
> you run an executable. Wouldn't it make sense to run them immediately after
> compilation? I mean, what would be the use case where you would want to 
> re-run a
> unit test on the code that's already compiled and tested? This could also 
> solve
> the problem with messages on success, since you can output a success message 
> after
> compilation.
> 
> Sorry if I'm missing some obvious issue with this suggestion.

Off the top of my head, I see two reasons why running the tests
separately is a good thing:
 - It allows to run the test in a debugger;
 - Cross-compilation.

Jerome
-- 
mailto:jeber...@free.fr
http://jeberger.free.fr
Jabber: jeber...@jabber.fr

Re: "Try it now"

[Adam D. Ruppe]

On Wed, Apr 13, 2011 at 07:37:08PM -0500, Andrei Alexandrescu wrote:
> This is very close already! Two things if you get to work on this for 
> the weekend:

Try it now:

http://arsdnet.net/d-web-site/std_algorithm2.html


Getting the console window to resize was a bit of a trick.. actually, the most
painful part of the whole thing, by far! I think it's a hack too, to get around
cross domain restrictions but it works for me.

Re: "Try it now"

[Adam D. Ruppe]

new version of javascript up:
http://arsdnet.net/d-web-site/std_algorithm2.html

Re: "Try it now"

[bearophile]

Adam D. Ruppe:

> new version of javascript up:
> http://arsdnet.net/d-web-site/std_algorithm2.html

I suggest to add a spinning circle for the compilation wait (see Ideone site 
too).

Some comments on the code examples:
- The second example for reduce(), the example of group() and minCount(), the 
third example of remove() need tuple
- The example of uninitializedFill, initializeAll and schwartzSort contain 
dummy ... code
- The filter() example gives Error: incompatible types caused by:
auto small = filter!("a < 3")(arr);
assert(small == [ 1, 2 ]);
- Splitter() example gives another Error: incompatible types
- the first and second examples of find() gives a import conflict error
- The third find() example doesn't find tuple and gives a missing overload error
- The example of endsWith() gives algorithm.d(3127): Error: no property 'empty' 
for type 'char'
- findAdjacent() lacks an auto p = ...
- balancedParens() gives an assert error
- The example of equal() gives a approxEqual error and more
- levenshteinDistance() gives Error: static assert  "Bad binary function 
q{toupper(a) == toupper(b)}. You need to use a valid D expression using symbols 
a of type dchar and b of type dchar."
- levenshteinDistanceAndPath() gives a algorithm.d(3975): Error: undefined 
identifier Range, did you mean alias Range1?
- The window formatting of bringToFront() seems wrong
- The second and third bringToFront() examples lack SList
- The 4th and 5th examples of remove() give an assert error
- The topN() example doesn't find "less"
- completeSort() gives some problems, maybe it can't find assumeSorted()
- makeIndex() example gives a template error
- topNCopy() example gives an error, maybe it's wrong
- setIntersection() example asserts statically
- largestPartialIntersection() and largestPartialIntersectionWeighted() can't 
find Tuple

Thank you for reminding me how hugely useful is the Python doctests module :-)

Bye,
bearophile

Re: "Try it now"

[Andrei Alexandrescu]

On 04/17/2011 01:22 PM, Adam D. Ruppe wrote:

new version of javascript up:
http://arsdnet.net/d-web-site/std_algorithm2.html


One more thing: make sure you solve potential cross-site scripting that 
may occur, and prepare for seeing a fair amount of extra traffic. In the 
long run we'll prepare d-programming-language.org to handle the examples 
itself.


Thanks,

Andrei

Re: "Try it now"

[Andrei Alexandrescu]

On 04/17/2011 01:22 PM, Adam D. Ruppe wrote:

new version of javascript up:
http://arsdnet.net/d-web-site/std_algorithm2.html


Great. I think this looks adequate now and ready for integration into 
d-programming-language.org.


Adam, could you please put together a pull request on github?

I'd also appreciate if you sent my way a simple script that scrapes the 
HTML for all sample code so we can work on making them work.



Thanks,

Andrei

Re: "Try it now"

[Andrei Alexandrescu]

On 04/17/2011 02:00 PM, bearophile wrote:

Adam D. Ruppe:


new version of javascript up:
http://arsdnet.net/d-web-site/std_algorithm2.html


I suggest to add a spinning circle for the compilation wait (see Ideone site 
too).


Probably we're good to go without that, but it'll help once the traffic 
increases :o).



Some comments on the code examples:

[snip]

Since you already made a pass, I suggest you write a few pull requests 
on github that make examples work.



Thanks,

Andrei

Re: "Try it now"

[Adam D. Ruppe]

Andrei Alexandrescu wrote:
> Adam, could you please put together a pull request on github?

I've gotta figure out how that works...

> I'd also appreciate if you sent my way a simple script that scrapes
> the HTML for all sample code so we can work on making them work.

Heh, what a coincidence. I just wrote a quick one now:

http://arsdnet.net/d-web-site/extractexamples.d

It's cgi so you can see the output here, but it's trivial to
change, very short program. Fetch my dom library here
http://arsdnet.net/d-web-site/arsd/dom.d

Example output:
http://arsdnet.net/d-web-site/extractexamples


It puts in some generic imports, an empty main, and wraps
everything in unittest {}.

Re: "Try it now"

[Adam D. Ruppe]

Andrei Alexandrescu wrote:
> One more thing: make sure you solve potential cross-site scripting
> that may occur

I don't think any are possible - I always escape input and output,
and if something does get through, it's on a different domain so
the browser's cross domain restriction will keep it from getting
too bad. (Indeed, these restrictions made the auto-resize a real
pain in the ass!)

> and prepare for seeing a fair amount of extra traffic.

Naturally.

Re: "Try it now"

[Andrei Alexandrescu]

On 04/17/2011 02:29 PM, Adam D. Ruppe wrote:

Andrei Alexandrescu wrote:

Adam, could you please put together a pull request on github?


I've gotta figure out how that works...


I'd also appreciate if you sent my way a simple script that scrapes
the HTML for all sample code so we can work on making them work.


Heh, what a coincidence. I just wrote a quick one now:

http://arsdnet.net/d-web-site/extractexamples.d

It's cgi so you can see the output here, but it's trivial to
change, very short program. Fetch my dom library here
http://arsdnet.net/d-web-site/arsd/dom.d

Example output:
http://arsdnet.net/d-web-site/extractexamples


It puts in some generic imports, an empty main, and wraps
everything in unittest {}.


Looking good. Hmmm, I think we should just compile code as it is, no 
hidden artifacts. Then that adds some syntactic noise. Not sure what the 
best balance is.


Andrei

Re: "Try it now"

[Adam D. Ruppe]

bearophile wrote:
> I suggest to add a spinning circle for the compilation wait (see
> Ideone site too).

Am I actually the only person in the world who *hates* those things?

I might add it later though.

Re: "Try it now"

[Andrei Alexandrescu]

On 04/17/2011 02:35 PM, Adam D. Ruppe wrote:

bearophile wrote:

I suggest to add a spinning circle for the compilation wait (see
Ideone site too).


Am I actually the only person in the world who *hates* those things?

I might add it later though.


I think adding the text to the "Running...\n" as soon as you get the 
request should help.



Andrei

Re: "Try it now"

[KennyTM~]

On Apr 18, 11 02:22, Adam D. Ruppe wrote:

new version of javascript up:
http://arsdnet.net/d-web-site/std_algorithm2.html


There are some minor styling bugs. I've only tested it on Chrome 10.

For Example: code blocks:
1. Press "Try Now", then "Cancel" - the code block becomes bold.
2. Click "Try Now" again - the "Cancel" is now in the other line

For non-Example: code blocks:
1. The "Try Now" button appear below the code.
2. Click "Try Now" and "Cancel" moves the button above the code.



Also, I suggest the try-now examples should allow using a different 
piece of code than the one shown.


For instance, the introductory code (the sort one) of the std.algorithm 
module clearly shows what the module does, but it absolutely useless for 
Try-Now. The result is "Program ran successfully.", so what? The user 
should be able to see how the array is sorted, how to provide a custom 
predicate, etc., and thus writeln's need to be placed after the 3 sorts. 
This can't be automated by Javascript.


I like the w3schools approach (except the new window part), where the 
main page shows a concise example to let people understand how the 
feature is used, and the "Try it yourself" link provides a complete 
program with human-readable output.

Re: "Try it now"

[Andrei Alexandrescu]

On 04/17/2011 02:29 PM, Adam D. Ruppe wrote:

Andrei Alexandrescu wrote:

Adam, could you please put together a pull request on github?


I've gotta figure out how that works...


Oh, and I think learning git/github is a huge net gain outside of any 
particular project. I warmly recommend it.


Andrei

Re: "Try it now"

[Adam D. Ruppe]

KennyTM~ wrote:
> There are some minor styling bugs. I've only tested it on Chrome 10.

Oh, I see it too. Fixed.

Re: "Try it now"

[Adam D. Ruppe]

Andrei Alexandrescu wrote:
> Oh, and I think learning git/github is a huge net gain outside of
> any particular project. I warmly recommend it.

Yeah, I've used git before on the command line, but never the
website.

I'll admit though that for my typical project, my idea of source
control is commenting and/or remembering how many times to hit undo
in the editor...

But when I dive into this, most the change is trivial - the script
and server side program do almost all the work. But I'd like to
at the least fix some invalid html in std.ddoc too. Both browser
scripts and my D dom module are able to figure it out anyway, but
it'd be nice if the HTML was more well formed and maybe using
better semantic tags/classnames.

Re: "Try it now"

[Walter Bright]

On 4/17/2011 11:22 AM, Adam D. Ruppe wrote:

new version of javascript up:
http://arsdnet.net/d-web-site/std_algorithm2.html


Adam, this is really awesome work!

Some trivial nits:

1. The output window is offset 3 or 4 pixels to the left of the source window.

2. The source window has a 1 pixel box around it. The output window has a two 
pixel border on the left and top sides only. This makes it look out of place.


3. The lime-green-on-white text in the output window is a little hard to read 
comfortably. Perhaps a darker green?


I'm running IE9 in case these issues are browser specific.

Re: "Try it now"

[Walter Bright]

On 4/17/2011 12:36 PM, Andrei Alexandrescu wrote:

I think adding the text to the "Running...\n" as soon as you get the request
should help.


Or:

"Please wait while the D-9000 computer boots..."

Re: "Try it now"

[Andrew Wiley]

On Sun, Apr 17, 2011 at 3:01 PM, Walter Bright
 wrote:
> On 4/17/2011 12:36 PM, Andrei Alexandrescu wrote:
>>
>> I think adding the text to the "Running...\n" as soon as you get the
>> request
>> should help.
>
> Or:
>
> "Please wait while the D-9000 computer boots..."
>

Or
"Must DESTROY John Connor!"

The console background is green on black over here on the Chrome 12
dev build, so there's definitely something browser specific going on.
And let me join the list of people saying this is friggin awesome. Thanks, Adam!

Re: "Try it now"

[Bruno Medeiros]

On 13/04/2011 23:39, Adam D. Ruppe wrote:

* Syntax highlighting in the editor :o)

I'm afraid I'll have to say no here... that's a pretty enormous
effort to get working well, and I hate javascript too much to
spend that kind of time with it. Of course, if someone else
has done it, I'm not above a little copy/paste action.


Hum, this seems like the kinds of things where the new Eclipse Orion 
project might be interesting and useful to integrate with:

http://www.eclipse.org/orion/

--
Bruno Medeiros - Software Engineer