Block Diagrams as a Syntactic Extension to

Abstract. Often, the semantics of languages are defined by the products that support their usage. The semantics are then determined by the source code of those products, which often is a general-purpose programming language. This may lead to complications in defining a clean semantics, for example because imperative notions slip into a declarative language. It is illustrated how block diagrams can be translated into Haskell to define the semantics of a graphical language in terms of a textual programming language. This also allows the use of block diagrams as a syntactic extension to Haskell and the use of Haskell as an action language in block diagrams. Imperative notions can then be included from the declarative perspective of Haskell, which is more constrained and less prone to resulting in complicated semantics of interaction and combination of the imperative and declarative.