A Ruby script that creates a dependency graph of installed or all available Homebrew formulae. The currently supported output options are Dot and GraphML. The Homebrew distribution contains a similar, script written in Python which describes the dependency graph in the Dot language.
ruby brew-graph.rb -h to display a list of available options.
You can use Graphviz to visualize Dot graphs.
brew install graphviz brew-graph | dot -Tsvg -odependency_graph.svg open dependency_graph.svg
You can use the yEd graph editor to visualize GraphML markup. The created markup uses yFiles's extensions to GraphML and heavily relies on defaults to keep the output reasonably small. It contains no layout information because yEd already provides an exhaustive set of algorithms.