The project is split into a few seperate repositories.
gemgen is the command line tool for converting Commonmark Markdown to Gemtext.
goldmark-gemtext is a goldmark renderer which renders parsed markdown to gemtext instead of html.
golemark-wiki is an extension to the goldmark markdown parser. It adds support for a new link syntax used by vim wiki and some other wiki software.
main.go - Short and simple main function that calls the argument parser, loads
templates, and then converts STDIN or named files.
options/options.go - Command line argument parser that builds up an Opts
struct containing a list of files to convert, options for goldmark, list of
templates, and an output directory.
matchtemplate/matchtemplate.go - Defines a type that associates a
text/template with a list of files which have been matched by a regular
expression.
convert.go - Provides a Convert and ConvertFiles functions. The latter
concurrently reads and converts a list of files using Opts and a list of
MatchTemplates. The former does the same conversion, but from an io.Reader to an
io.Writer.
render.go - Implements the basic functions and methods for a goldmark
Renderer, including registering a method for each AST type the renderer can
handle.
option.go - Defines a Config type which can be given to the GemRenderer to
adjust its output. Each value in the config can be set with a helper function
such as WithHeadingLink rather than building the whole config individually.
block.go - Contains GemRenderer methods for "Block" elements, headings,
paragraphs, lists, etc.
inline.go - Contains GemRenderer methods for "Inline" elements such as
emphasis, links, codespan, etc.
extra.go - Contains GemRenderer methods for non-standard markdown elements
such as strikethrough, wiki links, and check boxes.
wiki.go - Defines a goldmark parser extension for the wiki type and even a
basic HTML renderer. A lot of this is boiler plate and not technically used in
gemgen, but could be used in other goldmark projects that need wiki link
parsing.
ast/wiki.go - Defines the AST node to represent the wiki link element.
The project uses a public mailing list for patches and communication: https://lists.sr.ht/~kota/gemgen You can create a post by sending plain text emails to ~kota/gemgen@lists.sr.ht.
Read the man pages and see if anything seems wrong or unclear. I don't have the perspective of someone reading it for the first time.