* foldl
:PROPERTIES:_

Problematic with ~foldr~ is that it recurses out to its full length
before performing the given function's task. For example, with

#+begin_example
foldr (+) list
#+end_example

~(+)~ behaves strictly, meaning that both arguments to it must be
fully evaluated before ~(+)~ can return a result. Hence, for

...

Problem is I've borrowed (some, most, all of) this from an online source and I want to credit the source. What would be nice is to be able to select a region -- however big or small -- and create a log/note/footnote etc. about the selected region -- in my case, give reference.

Of course I could just tack a footnote at the end of the borrowed stuff, but then in the case of multiple preceding paragraphs, formulae, etc. it would be hard to indicate where the particular borrowed parts began -- without resorting to ugly marker kludges.

So yes, simply being able to select regions and make side notes about them could give you a very fine level of control over metadata in a file. Is there such a thing in the Emacs/org-mode world?

LB