[Python-Dev] readd u'' literal support in 3.3? (original) (raw)
Tres Seaver tseaver at palladion.com
Thu Dec 8 20:03:15 CET 2011
- Previous message: [Python-Dev] readd u'' literal support in 3.3?
- Next message: [Python-Dev] re.findall() should return named tuple
- Messages sorted by: [ date ] [ thread ] [ subject ] [ author ]
-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1
On 12/08/2011 12:26 PM, "Martin v. Löwis" wrote:
It would make it possible to share code like this across py2 and py3:
a = u'foo' Instead of (with e.g. six): a = u('foo') Or: from future import unicodeliterals a = 'foo' I recognize that the last option is probably the way "its meant to be done", but in reality it's just more practical to not fail when literal notation is more specific than strictly necessary. You are giving these two options already: - The former works for all Python versions. Although it may appear tedious to convert existing code to replace all Unicode literals with function calls, it would actually be possible/easy to write an automatic converter that does so for a complete code base, based on lib2to3.
I guess this could be done to generate "straddling" code from 2-only code. Note that the overhead of the function call is likely significant in some cases: generating a module scope constant is the only sane replacement there, which might be harder to do in a fixer (I haven't tried to write one yet).
- the second version is truly practical for all applications/libraries that only support 2.6+.
Right. The question is would running more P2 code unmodified in P3 be a "Good Thing" from the perspective of P3 uptake: developers who run up against such issues tend to hit "camelback-meet-straw" points and bounce off the effort. Such a tiny change (a six line patch and an extra '.. note::' in the language reference section on string literal syntax) might be worth avoiding that risk.
In addition, there also is another option: - use 2to3, in some form
2to3 is not practical in a "straddling" case:
- The script is too slow to use in development mode (like being back in "compile the world" Java / C++ land).
- The transformed code generates tracebacks that don't match the source.
So you have already three solutions which are all transitional in some sense, and you want yet another option? I fail to see why this option is more practical than the options that are already there.
The "redundant" u'' spelling would be present in Python3 for the same reason that the equally-reduntant b'' spelling is present in Python 2.6+: it makes writing portable code simpler.
Tres. - --
Tres Seaver +1 540-429-0999 tseaver at palladion.com Palladion Software "Excellence by Design" http://palladion.com -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.10 (GNU/Linux) Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org/
iEYEARECAAYFAk7hCfIACgkQ+gerLs4ltQ5t8wCfalykXvpSq6awllQUpCymf8iM 3P0An0cCY/iZHcK82V+CqW07wCpGfBtf =Q4Fv -----END PGP SIGNATURE-----
- Previous message: [Python-Dev] readd u'' literal support in 3.3?
- Next message: [Python-Dev] re.findall() should return named tuple
- Messages sorted by: [ date ] [ thread ] [ subject ] [ author ]