The static call tree of a Fortran Program is shown as a directed graph, where each node represents a function or a subroutine and the edges show the caller-callee relationship between two nodes. This view was developed using Zest, a set of visualization components built for Eclipse. The main feature of Zest is that it makes graph programming easy. The basic purpose of this view is to help programmers to understand easily the relationships between program components and to obtain a clearer picture of how complex the connections among these program components are.

The static call tree implementation has two major components. The first one is based on Photran VPG (Virtual Program Graph) and it is used in order to obtain the source code representation as an AST (Abstract Syntax Tree). A Visitor pattern is used to build the Static Call Tree by visiting a set of nodes such as functions, subroutines, main/program, and call statements. The second component is used to show the static call tree once it was built from the AST. In order to achieve it, the JFace infrastructure of zest was used to allow this implementation.