On 9/23/2012 6:57 PM, Ian Kelly wrote:
On Sun, Sep 23, 2012 at 4:24 PM, Joshua Landau
<joshua.landau...@gmail.com> wrote:
The docs describe identifiers to have this grammar:
identifier ::= xid_start xid_continue*
id_start ::= <all characters in general categories Lu, Ll, Lt, Lm, Lo,
Nl, the underscore, and characters with the Other_ID_Start property>
id_continue ::= <all characters in id_start, plus characters in the
categories Mn, Mc, Nd, Pc and others with the Other_ID_Continue property>
xid_start ::= <all characters in id_start whose NFKC normalization is in
"id_start xid_continue*">
xid_start is a subset of id_start
xid_continue ::= <all characters in id_continue whose NFKC normalization is
in "id_continue*">
xid_continue is a subset of id_continue.
So I would assume that
exec("a{} = None".format(char))
would be valid if
unicodedata.normalize("NFKC", char) == "1"
Read more carefully the definition of xid_continue. The un-normalized
character must also be in id_continue.
as
exec("a1 = None")
is valid.
BUT "a¹ = None" is not valid*.
>>> ud.category("\u00b9")
'No'
Category No is *not* in id_continue, and therefore not in xid_continue.
exec("x\u00b9 = None") # U+00B9 is superscript 1
On the other hand, this does work:
exec("x\u2071 = None") # U+2071 is superscript i
So it seems to be only an issue with superscript and subscript digits.
Looks like a compiler bug to me.
The problem, if there were one, would be in the tokenizer that finds
identifiers. However,
>>> exec("x\u00b9 = None")
...
x¹ = None
^
SyntaxError: invalid character in identifier
this is correct.
--
Terry Jan Reedy
--
http://mail.python.org/mailman/listinfo/python-list
