Re: [Wrapl-discussion] How to invoke such method :"@"?

[Raja M. <raj...@gm...>]

On 30 May 2010 10:37, Roman Mishin <rom...@gm...> wrote:

>
>>> VAR text <- mylist@String.T;
>>
>
> Indeed. I have already used @ to convert an integer to a string in MOD
> Bottles. I think I didn't get the very thing that the type itself is used as
> an argument.
>
> You can also use
>>
>> mylist@(String.T, " ")
>>
>
> I come up with such line:
> Out:write(verse[2,0]@(String.T, "") + verse[1]);
> I tried it on a Linux machine with the latest Wrapl version and it works.
>
> but I'm not very happy with this syntax and am still open to suggestions
>> about changing it.
>>
>
> Perhaps being not so intuitive at first sight, it seems OK to me. Knowing
> that this syntax comes from a general rule of how to call a method, it seems
> acceptable.
>
> The first thought on how to change it is to use something similar to:
> mylist @ String.T VIA " "; analogous to :"[]=", and possibly using some
> special character :"@~" (mylist @ String.T ~ " ";). This is from my
> perspective, however.
>

Hmm, my idea for using the syntax I chose was that it should be possible to
call @ with any number of parameters.  I hadn't thought of using a method
similar to :"[]=", but will consider it.


>
>

> By the way, you're the first person to seriously try using Wrapl, so the
>> online documentation may be a bit lacking in places. I'll try to improve it
>>  based on your comments.
>>
>> Also, the Windows port of Wrapl is a bit out of date, I don't think any of
>> the versions of @ with 3 or more arguments are implemented in it. Since your
>> last comment, I have mostly fixed the Windows port and will put the new
>> version on the website within the next week.
>>
>
> Thank you. Most of the time I work on Windows. Recently, though, I set up a
> Linux machine to experiment with. If you are interested, here is a little
> bit of my experience with Wrapl installation on Linux:
>
> --
> I set up a fresh Debian-compatible distro - Linux Mint - on VirtualBox.
> Then I installed both wrapl-1.7.1041.deb and wredit-1.7.1041.deb. Some
> dependencies were installed by package manager. The whole installation went
> without an issue. In the shell I got this:
>
> roman$ wrapl
> Error: /usr/lib/libtermcap.so: undefined symbol: setupterm
> Error: symbol setupterm not exported from libtermcap
> Error relocating [82d7808] /usr/lib/riva/Util/Tecla.riva:93
>
> As I found out this relates to the Wrapl interpreter only, not to riva.
> "Hello World" scripts were working.
>
> I searched for "termcap Debian" and found this page
> http://archive.debian.net/bo/admin/termcap-compat which explains
> incompatibility between termcap and current Debian versions. So I installed
> the package mentioned on the page. Yet, it didn't help. The error remained.
>
> The page also mentions libncurses, so in search for a solution the next
> thing I did is installed libncurses5-dev package, since libncurses5 was
> already in place. And this did help. Wrapl started right away.
>
> With not much experience, I think the only missing dependency is some
> library in libncurses5-dev package.
>

Thank you for this useful feedback, I will be sure to add this dependency to
the next release.


> --
>
> Going further, I want to ask how to read this descriptions in
> Libraries:Agg:List:
>
> :"="(_ @ T, _ @ T, _ @ Agg.ObjectTable.T)
> Does it compare two lists? [1, 2] = [1, 2]; I am getting "failure".
>

I think this method is only defined in the latest version, which I have just
uploaded to the website, along with an updated Windows version (any feedback
on this is appreciated). The Windows version is still missing a few modules,
in particular all the Gtk based modules, and for now the Stat.* and
Math.Random modules, since they haven't been ported to build correctly on
Cygwin yet.


> What is third argument?
> Does underscore have special meaning in descriptions or it just denotes
> "something"?
>

Yeah, _ is just used to denote "something", it is automatically generated by
the documentation generator whenever actual descriptions are missing. It is
also used for value paramters (=) since the parameter name doesn't really
matter.


>
>
>
:"@"(_ @ T, _ = Std.String.T)
> this seems similar to:
> :"@"(list @ T, _ = Std.String.T, sep @ Std.String.T) : Std.String.T
> but without separator and it does not define return type. It works:
>

The former returns a Std.String.T like the latter, but hasn't been
documented yet.


>  --> VAR s <- mylist@String.T;
> [one, two, three]
> --> ? s;
> C:\Wrapl\lib\Std\String.T
> But I honestly wonder, is this practical after a conversion to have a
> string formatted as list?
>

The list is actually converted into a string in this form, no formatting of
the string is performed afterwards. This conversion is mainly intended for
displaying the list. The second method for converting a list to a string
(with a seperator) is probably more useful within an application.


>
> --
> Roman
>

Raja