reading symbols containing apostrophe

[Tom Gillespie]

Hi,
   I'm in the processes of reviewing reader behavior for a number of
different lisp dialects and Guile has a quirk that I have been unable
to find any documentation about. Specifically, as far as I can tell
apostrophe is not allowed in identifiers according to the formal
grammars for r5rs through r7rs (I have not checked earlier versions).
In addition apostrophe is not included in the extended reader syntax
in the manual. However, 'a'b'c reads as a'b'c in guile 2.2.6. Am I
missing something? Is this a bug?

Best!
Tom