explanation

The essential package is provided in lint.go, which just provides two functions, Lint() and Spew(). Lint() is the important function; it will take a filename and a []byte representing an input file, and return a []string where each line contains an error message. Spew() will print the internal representation of a YAML file for debug purposes.

Each subdirectory contains a small package used in lint.go. workflow/ contains the Go types used to represent the YAML structure, separated into different files for the different possible pieces of a GitHub workflow. Each other directory contains a small package for linting that section of the workflow, supplying a single Lint() function to be called in lint.go.

For future maintainers: as you can see, only root/, name/, jobs/, and on/ have directories right now, and of those only the first three have useful lints. When extending development, consider making a new directory for each of the other top-level GitHub properties, putting a small package in each, and continuing the pattern already established. As for the workflow/ directory, most of the code there is finished, but you can double check that all the data in the YAML file is represented by adding the -d flag or running Spew(). The workflow/on/ directory is most likely to need another look; there are several interface{} values that can be replaced with a more descriptive type system.