NS Basic/Palm 2

Most professional programmers writing for PDAs running the Palm operating system, will be working in a dialect of C++ or with Java. NS Basic for the Palm platform is designed to be a low-cost RAD (Rapid Application Development) tool based on a dialect of Basic. If you're planning to target the Palm world with your next application, this could be just what you're looking for.

Although new users should be given more information on how to set up this useful development aid, straightforward installation from the CD was trouble-free. The software emulator for Palm devices installs by default, although as the emulator was already set up on my PC this wasn't such a boon and the installation routine should have located this.

Once installed, the software has a clear and straightforward interface reminiscent of the familiar Visual Basic style. The rather thin toolbar for the controls looks a little odd but it saves on screen space. As in VB, program code is associated with individual controls and forms with shared subroutines and functions being placed in code modules. Rather neatly, most of the source code for a project is collected into a single project file, which is saved by default into a common directory. Code modules are saved as separate files to facilitate code sharing between projects.

A good range of controls has been provided. This includes the expected button, list, label, textbox, radio button and checkboxes. These are joined by objects such as the Selector and Gadget that allow the developer a fair degree of opportunity for customisation. There's also a graphic control, a pop-up trigger and another called the Repeater. This will trigger any associated code continuously while the user holds the stylus down. Finally, there's full support for menus on your forms.

The controls are matched by plenty of built-in language functions that leave no major gaps. The GNU Mathlib library of double-precision maths functions is supplied on the installation CD and is made available to you by default. The advanced programmer also has access to the PalmOS API. There's good support for any available serial port on your device so that you can programmatically control access to modems or other serial devices. I was also glad to see additional libraries being supplied to support the CSM 150 barcode scanner available for the Handspring Visor and the extended audio and visual facilities of the HandEra 330 PDA.

I decided to see how easily I could reproduce an existing Palm program using the wider range of controls available in NS Basic. Progress was satisfyingly fast and the additional controls meant I was able to improve the look and feel as I went along.

Using the Code Editor to add program code to click events on controls or to forms was intuitive. The Editor makes good use of colour to identify keywords and operators. This helps to get the syntax right as this is only checked when you request a 'compile'. Getting used to any new language (even a new Basic) can take time, but I found the supplied documentation was adequate, if a little terse.

The language supports the standard Palm pdb data structure, but NS doesn't supply any database conversion facilities. For business applications it would be necessary to download the Conduit Development Kit from Palm to create a software plug-in for the HotSync Manager. This means a developer may need something like C++ or Visual Basic available to complete a commercial project.

Sadly, there's no support for any kind of managed error recovery during program execution. Certain key data access and serial communications functions do return values that can be inspected and associated errors identified. This makes very defensive programming a necessity and will certainly demand Extended Desktop testing with the Palm emulator, which does have debugging facilities built in.