Steve's Programming place

I've been working with VID 2 this week (Visual Interface Dialect), yes it's a dialect. A dialect is an extension to the REBOL language that can be 'plugged-in' to extend the language itself. In the case of VID it's used to create GUI'S (Graphical User Interfaces).

VID 2 is quite powerful but some of my questions to the ever patient (Rebol Guru's) have been answered with 'well in VID 3 it will be a LOT easier!'. So with a public 'alpha' release being available I thought I'd dip my toe in and have a look.

We don't need to do anything complicated to see quite a difference.

Let's try a one-liner - if we look at example 1 the first thing I noticed is that 'effects' are now 'options' this is more logical I think. A couple of additions I really like are 'rounding' which allows us to create a button, box etc and specify how rounded the corners should be. We also have 'material' which include sand, glass, blue-glass etc, Stylising these should allow some pretty funky skins.

Running the script creates fig.1

Right now try re-sizing the screen!

Firstly, the screen is re-sizable by default - nice, but also see how the button has re-sized itself accordingly. This is because VID 3 will include a 'table' style layout manager this arranges controls in virtual columns working on a top - down basis 

You can have a look at many more cool styles you can play with at the following link

Rebol VID User Guide

Steve

Henrik from HMK as passed on a postscript on how styles will be used in VID 3

example 1

view [ button "Hello World!" options [rounding: 8  material: 'sand] ]

Fig1.

 
Fig2.

Courtesy of HMK Design

"'effects' are now 'options'" - the idea is here to remove the need for face hacking. Options is a clean, self documentable  way to alter the settings for a specific style. But here, the fact that we can alter the appearance of the style is a bit of a fluke, because we wanted a simple way to test options. Originally it was the idea that altering any such effects parameters directly in your layout would be prohibited; The style would take care of this internally and you'd use specific button types that would then use a specific style. You would use buttons defined through its purpose rather than its appearance. You'd have zero control over the appearance of the button, because that is controlled by the style alone.

I know that sounds a little terrifying, but VID3 is meant to lift styling to a whole different level; You don't style every single face. You focus on the contents of your UI, and the purpose of each element, rather than its appearance and VID3 works out how to display it. This is for multiple reasons:

- VID3 can display on other devices than bitmapped displays, such as text consoles or vectored output.
- Styling becomes the job of one or more dedicated developers rather than the application developer, which standardizes styling. It makes it much simpler to build very large applications and it becomes possible to switch consistently between different styles, where one won't look crappy while another one looks great. They'll work equally well. Compare it to VID which is just the Wild West of styling. :-)
- Abstraction will make it possible to identify parts of a user interface, such as allowing VID3 to, on its own, find the cancel button in a window or automatically put key focus on the correct button for great consistency.

So when you, in your user interface design say: "I want a button that shows importance", you don't try to make a red button. You could use the 'warning-button style (just an example, doesn't exist yet). Similarly there will be styles for ok-button, cancel-button, etc. They are not called red-button, yellow-button, but are purely purpose oriented styles.

So while VID3 may look like just a prettier VID with resizing in a one-button example, it's actually a whole different beast. :-)

Well we're into the second week of learning REBOL.

While the applet on the right is only a dozen lines of code, it showed me a few thing about REBOL. Firstly I was trying to do something quite simple - I wanted the name to be forced into uppercase. We needed to select the expiry date and create an encoded licence. In your event handling of the name box you can 'bind' to the base text handler called ctx-text. This allows us to 'interrupt' the key-presses and change them to uppercase.

On a full-blown application I can create functions for interrupting key-strokes and getting the effect I want. HOWEVER! this is a lot of work for a twelve line applet, all this applet needed was  'cname: field [uppercase cname/text]', when you leave the field it's converted to uppercase.

Still struggling with 'BIND' but  I think I've learned enough about PARSE, BIND, CONTEXT & DIALECTS, to start using some of these facilities in some programs.  Biggest lesson so far this week has been 'Don't use it just because it's there!'  Stepping back from some of the things I've tried have lead me to simplifying my program rather than achieving a complicated solution!

If you've started using REBOL - please let me know how your getting on.

Steve

Well it's a week since I started learning the REBOL Development System.

I think it's one of the most productive languages I've ever come across. I've used the (MS) Visual Studio languages since they came out - all the way back with Visual Basic 1.0. Lots of people laughed at it when it was released saying it was only any use for prototyping! Well it and Visual Studio have become about the most successful languages at 'Getting people programming'.

I see the same kind of simple power with REBOL. At first glance I didn't think it could compete when doing any serious desktop applications - I thought it was just an effective web language like Ruby! In the past week I've found it to be very powerful. Apart from trying to read the mountain of documentation available on the REBOL web site, I have been prototyping a couple of applications one is a relationship management come document tracking system and the other is a re-write of a booking system I wrote in VB6.  I'll let you know how I get on over the coming months.

On the right is a screen shot of the relationship manager, I'm quite pleased with rich feel it's possible to achieve with REBOL. To do the same effects with Java I would need to link several widget & graphic libraries (Never again!)

The icons at the bottom are made from plain old boxes, but the reflection is created with one line of code (per icon) and when you hover the mouse over the icons they expand (Mac - toolbar) style. Hovering also shows a description of each item at the bottom of the screen.

One of the big differences with REBOL is the community! it's second to none. I must give a big thank-you to Henrik, Gregg and others for their patience with me this week.

Please have a go at REBOL and let me know what you think.

Regards

Steve