Bahr and Hutton recently developed an approach to compiler calculation that

allows a wide range of compilers to be derived from specifications of their

correctness. However, a limitation of the approach is that it results in

compilers that produce tree-structured code. By contrast, realistic

compilers produce code that is essentially graph-structured, where the edges

in the graph represent jumps that transfer the flow of control to other

locations in the code. In this article, we show how their approach can

naturally be adapted to calculate compilers that produce graph-structured

code, without changing the underlying calculational methodology, by using a

higher-order abstract syntax representation of graphs.