{flow} provides tools to visualize as flow diagrams the logic of functions, expressions or scripts and ease debugging.

Use cases are :

• Deciphering other people’s code
• Getting more comfortable with our own code by easing a visual understanding of its structure
• Documentation
• Debugging
• Inspect unit test results
• Providing a higher level view of an algorithm to collaborators
• Education

Install from CRAN with:

install.packages("flow")

Or install development version from github:

remotes::install_github("moodymudskipper/flow")

library(flow)

Using default nomnoml engine

flow_view(rle)

Using plantuml engine (make sure the {plantuml} package is installed).

flow_view(rle, engine = "plantuml")

• flow_run() to display not only the diagram, but the logical path taken by a specific call
• flow_compare_runs() display the logical path of 2 calls to see where they diverge
• flow_debug()/flow_undebug() to use basically use flow_run() on a function wherever it’s called
• flow_view_vars() to display the dependencies between variables in a function
• flow_view_deps() to display recursively all the functions that your function calls
• flow_view_uses() to display recursively all the functions that call your function
• flow_view_shiny() to display the modular structure of your shiny app
• flow_view_source_calls() to display dependency tree of scripts sourcing each other
• flow_doc() to build a package’s documentation using flow diagrams
• flow_test() to show what happens in your unit tests
• flow_embed() to embed diagrams in your documentation.

See more in vignettes.

Make sure to check the vignettes for a detailed breakdown of all features.

{flow} is built on top of Javier Luraschi’s {nomnoml} package, and Rainer M Krug ’s {plantuml} package, the latter only available from github at the moment.