Does Blender Provide any Edge Loop identification in Mesh or BMesh? If yes, what is the link or document that describe such support?
Showing edge indices of a selection. Image Above.
Crude Console Output from a Python Blender Script. Please excuse the many flaws of omission and commission in presentation and explanation. The intent is to show cyclic and non cyclic edge loops. Simple Case. The arrow shows a correspondence between selected edges and console text. The text will be transformed into text compatible for Python Execution. Click to see larger image for improved readability. Image above.
Blender Python Code Sample. Subject to extreme cleansing and refactoring. Read at your own risk. Image Above.
Probably inessential and subject to deletion
Console Window Output with debug identification.
ED_undo_push: Loop Select wm_handlers_do_intern: handled! 'MESH_OT_loop_select'
Just to clarify I am talking about the connected edges the users see when they Alt-Click in edit mode and perhaps other selections.
Here is an example context
Given a edit mode selection or vertex group selection. Consider only the selection as though it were isolated.
How many cyclic and non cyclic edge loops are present? What are they?
The answer might be a Python list of lists of vertex indices.
I am asking for a reference to tested Python in this question. I am not asking for new Python to be written.
I have some Python script. I do not want to reinvent functionality. Although there could be some merit in Blender Python programming exercise. This analysis is not supposed to be the most general case. It might not even need to algorithmically efficient such as big O = n squared. Preprocess.