  With recent advances in graphical user interfaces, more and more tasks on
computers have become easier to perform. Out of the belief that creating
computer programs can also be one of them, visual programming languages (VPLs)
have emerged. The goal of VPLs is to shift a part of work from the programmer
to the IDE so that the programmer can focus more on algorithm logic than the
syntax of the implementation programming language. In this article, the methods
required to build a VPL are presented, with an emphasis on a novel method of
code generation in a WHILE language. Also, the methods for achieving basic
principles of VPLs will be shown - suitable visual presentation of information
and guiding the programmer in the right direction using constraints. These
methods are demonstrated on an example of vIDE, a VPL based on the Eclipse
integrated development environment (IDE). The design of vIDE with respect to
the Eclipse Graphical Modeling Framework (GMF) is described. The concept of a
flowchart graphical notation is examined in contrast with the algorithm model
it maps to. Finally, the disambiguity of the model representation of an
algorithm is discussed and the methods for transforming it to an actual
implementation in a programming language.
