Submitted by , posted on 06 November 2001

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This is a screenshot of a basic example program written in VPL, a visual programming language for embedded systems I developed for my final year computer engineering project.

The language supports most of the same constructs as text-based programming languages, like constants, variables, arrays, pointers, expressions, and functions with input parameters and return values.

Programs are structured into "libraries" of "components", the equivalent of functions. A library has a public interface and a private implementation. The implementation of a library can be specified independently of its interface, making it easier to port programs to different hardware systems.

VPL is a control flow based visual language, and has four objects to control program execution. The object that looks like an upside-down arrow is called a "begin", and is used to specify the start of a component. The red square object is called an "end", and is used to specify the end of a component. The pyramid-like object is called a "select", and is used to choose the path of a programs execution. Finally, the object shaped like a play-button is called an "execute", and is used to specify which objects to execute.

The language is represented on disk as a collection of XML objects, and compiles into both ANSI-C and 386 assembly source code.

If you want to contact me, email me at

James Stewart

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