Of course, as an Oberon Programmer, you would normally use Oberon's own text editor to edit texts. And that is really sufficient for almost any task. If not, there is always the possibility to enhance Oberon with extra features (like cursor control). On the other hand, in some cases the features of a universal Mac text editor like BBEdit can speed up some tasks, especially for viewing/editing/searching multiple files at a time. Provided that you don't care about any embedded styling information (see note below).
Increasing the luxury level when working with BBEdit, you can add "Language Modules" to it. These typically offer enhancements such as keyword and pre-defined identifier coloring, appropriate string and comment recognition, code block folding, and provision of a drop-down menu of functions (PROCEDURES in case of Oberon).
We make available a BBEdit "Codeless Language Module" for Oberon-07, which does all of the above. Although we tested it only on BBEdit 12.1.6, it may work as well on older versions (even TextWrangler).
To install the Oberon language module in BBEdit, read their instructions (mostly: put the "Oberon-07.plist" file in their "Language Modules folder", and restart BBEdit).
You may then also want to check their Preferences > Languages > Oberon-07 settings to:
It may also be helpful in "Custom filename extension mappings" to add "Text File" for non-Module text file extensions like ".Text", ".Tool"..
Oberon text files are always written with a (binary) header that contains styling information. Even if you don't add styling (fonts, etc.) explicitly. When using Oberon text files outside Oberon, this header is often undesired. For example, it can thwart the automatic recognition of line-end conventions in external editors, and changing Oberon text can invalidate the text "pointers" that are embedded in the binary header. Fortunately, Oberon can read text files without the binary header without problem, and then assumes a single default style.
So if you don't explicitly style the text, or don't care about existing styles. The header information can be deleted anytime. For this you could use the Directory.Convert command in Oberon (use it before you go to external programs, like editors or configuration management). Or delete the entire header information in your external editor.