5.2 Tags

Tags are used as meta-data for files: they facilitate interactions with notes where titles are insufficient. For example, tags allow for categorization of notes: differentiating between bibliographical and structure notes during interactive commands.

Org-roam calls org-roam--extract-tags to extract tags from files. It uses the variable org-roam-tag-sources, to control how tags are extracted. The tag extraction methods supported are:

1. 'prop: This extracts tags from the #+roam_tags property. Tags are space delimited, and can be multi-word using double quotes.
2. 'all-directories: All sub-directories relative to org-roam-directory are extracted as tags. That is, if a file is located at relative path foo/bar/file.org, the file will have tags foo and bar.
3. 'last-directory: Extracts the last directory relative to org-roam-directory as the tag. That is, if a file is located at relative path foo/bar/file.org, the file will have tag bar.
4. 'first-directory: Extracts the first directory relative to org-roam-directory as the tag. That is, if a file is located at relative path foo/bar/file.org, the file will have tag foo.

By default, only the 'prop extraction method is enabled. To enable the other extraction methods, you may modify org-roam-tag-sources:

(setq org-roam-tag-sources '(prop last-directory))

If you wish to add your own tag extraction method, you may push a symbol 'foo into org-roam-tag-sources, and define a org-roam--extract-tags-foo which accepts the absolute file path as its argument. See org-roam--extract-tags-prop for an example.