Terry J. Reedy added the comment: I reread https://docs.python.org/27/reference/lexical_analysis.html#encoding-declarations A first or second line must be a comment matching "coding[=:]\s*([-\w.]+)" (which IDLE uses) and the captured name "must be recognized by Python".
I also did some experiments. Apparently, "iso-latin-1-unix" is recognized by Python. On Windows, from an IDLE editor, # coding: iso-latin-1-unix runs, while # coding: xiso-latin-1-unix raises, during the compile(..., 'file', 'exec') call: SyntaxError: unknown encoding: xiso-latin-1-unix Since codecs.lookup() returns the same error for both lines: LookupError: unknown encoding: iso-latin-1-unix compile() must be doing something other than simply calling codecs.lookup. I suspect it somehow recognizes 'iso', 'latin-1', and 'unix' as valid chunks of an ecoding name. (The last might even be an obsolete legacy item.) Whatever it is, it is not obviously available to tools written in Python. Note that 'recognized as a legitimate encoding name' and 'available on a particular installation' are different concepts. I believe codecs.lookup implements the latter. ---------- _______________________________________ Python tracker <rep...@bugs.python.org> <http://bugs.python.org/issue28923> _______________________________________ _______________________________________________ Python-bugs-list mailing list Unsubscribe: https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
