The EurOS/2 Visual Age Smalltalk page

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By Martin Brampton

Visual Age Smalltalk is a highly effective Object Oriented development environment. Its original home was OS/2 and there are now versions for all flavours of Windows and for AIX. Generally, code developed for one platform can be easily ported to the others. This portability stems from the implementation of Smalltalk through a virtual machine. This, like the Java virtual machine, is relatively simple and can be implemented on other systems relatively easily. The Smalltalk class library can present rather more problems in porting to different platforms because of the different user interface and operating system functions available.

Contents

The IBM Visual Age Smalltalk home page

The obvious resource for Visual Age Smalltalk users is the IBM Visual Age Smalltalk home page . [1]

Cocking & Co

Romilly Cocking is internationally known as an OO expert, and has worked with all the major Smalltalk implementations, including Visual Age. The Cocking & Co web site provides a range of OO resources. [2]

Bloomsbury Software

The UK specialist distributors for Visual Age Smalltalk are Bloomsbury Software and their web pages provide information about the latest software releases both for Visual Age and for a range of related products. They also have many links to other Smalltalk resources.[3]

Component Manager

Concerned about the size of the distribution image for Visual Age applications? A possible solution is Component Manager which will package applications into Dynamic Component Libraries (DCL's). Dynamically swap components in and out of memory during runtime to dramatically reduce memory requirements. Dynamically repair a deployed application without redeploying the entire image. Dynamically connect to multiple DCLs. For Visal Age 3.x.

The Moore Stephens VA Web Connection demo

This is not guaranteed to be always running! As a computer facility it is trivial. What is important about it is the use of existing Smalltalk business objects. The example provides a simple VAT (Value Added Tax) calculator. You can keep entering different values, and the correct (we think) VAT is calculated each time.

The actual VAT logic is contained within an existing small group of Smalltalk business objects. These cooperate together to provide VAT functions. From them View Manager objects have been constructed which include not only the Smalltalk business objects, but also Visual Age interfaces to provide events suitable for building a user interface. Up to this point, the classes are quite general and do not include any particular user interface. They are being used in conventional GUI PC applications to run under OS/2.

But here, the MS Vat Calculator has a Visual Age Smalltalk Web Connection interface built round it, so as to interface to the World Wide Web. This means that our business systems can be interfaced to the web using all the same objects as are needed for local implementations, with only the final user interface implemented differently. Another example is the Moore Stephens Office Finder that involves no Smalltalk, but illustrates integration with the Moore Stephens Oracle database.

  • Last Revised: 29th October 1996