I declare that this thesis is my own account of my research and contains as its main content work which has not previously been submitted for a degree at any tertiary education institution. Joel Kelso ii The purported advantages of Visual Programming, as applied to general purpose programming languages, have remained largely unfulfilled. The essence of this thesis is that functional programming languages have at least one natural visual representation, and that a useful programming environment can be based upon this representation. This thesis describes the implementation of a Visual Functional Programming Environment (VFPE). The programming environment has several significant features. • The environment includes a program editor that is inherently

Space and time problems still occasionally dog the functional programmer, despite increasingly efficient implementations and the recent spate of useful profiling tools. There is a need for a model of program reduction that relates directly to the user's code and has a simple graphical representation. Nave graph reduction provides this. We address the problems of displaying a series of program graphs which may be long, and the elements of which may be large and complex. We offer a scheme for compacting an individual display by creating a quotient graph through defining equivalence classes, and a similar scheme for reducing the number of graphs to show. A metalanguage to allow the user to define compaction rules gives the model flexibility. A prototype system exists in a Haskell implementation. 1 Motivation People are often unable to predict the behaviour of a lazy functional program. Although the order of reduction is deterministic in a given sequential implementation, it is not intuit...