Error installing pyRdfaExtras due to tuple unpacking using Python 3.3

[dbs]

Although README.txt claims "The package has been adapted to Python 3", attempting to install pyrdfa3 under Python 3.3 fails with a syntax error in the pyRdfaExtras directory.

Steps to reproduce:

1. Setting up the environment:
   virtualenv --python=/usr/bin/python3.3 ~/schema_rdfa
   git clone https://github.com/RDFLib/pyrdfa3.git
   cd pyrdfa3
2. Installing the package:
   ~/schema_rdfa/bin/python setup.py install
3. Error:
   ...
   byte-compiling /home/dan/schema_rdfa/lib/python3.3/site-packages/pyRdfaExtras/init.py to init.cpython-33.pyc
   File "/home/dan/schema_rdfa/lib/python3.3/site-packages/pyRdfaExtras/init.py", line 112
   def add(self, (s,p,o)) :
   ^
   SyntaxError: invalid syntax

It looks like Python 3 dropped support for using tuples directly in method signatures like this five years ago via PEP 3113 (http://www.python.org/dev/peps/pep-3113/) with warnings added as of Python 2.6. I expect the alternative would be something like "def add(self, triple)" and then checking to ensure that triple[0], [1], and [2] were all defined.

Looking over RDFlib itself, it seems that the API is rife with tuple unpacking behaviour :/

[gromgull]

Without checking, I believe the tuple unpacking is fixed by 2to3 - maybe pyrdfa3 lacks a proper setup script that includes running 2to3, but pyrdfa is included in rdflib>4, there the installation defn. works for 3.2 and 3.3

[gromgull]

Actually checking, looks like it's exactly what happened: http://www.python.org/dev/peps/pep-3113/#transition-plan

[dbs]

gromgull: Thanks. Yes, if setup.py included a 2to3 step in this repository, that would correct the problem here, but it doesn't. Alternately, given that manually unpacking the tuples works in both Python 2.x and 3.x, I could work up a branch that removes the need for 2to3 for that purpose (leading to more legible code for those used to Python 2.6+). Not requiring a transform step should also make it easier for new contributors to pull the code from git & test & run it.

[iherman]

Dan,

sorry about that; I took care of this (and updated github).

As for the RDFLib core package, I wonder why this problem has not manifested itself already. I will forward your mail to those who really maintain the package...

Cheers

Ivan

On Aug 12, 2013, at 17:58 , Dan Scott notifications@github.com wrote:

Although README.txt claims "The package has been adapted to Python 3", attempting to install pyrdfa3 under Python 3.3 fails with a syntax error in the pyRdfaExtras directory.

Steps to reproduce:

• Setting up the environment:
virtualenv --python=/usr/bin/python3.3 ~/schema_rdfa
git clone https://github.com/RDFLib/pyrdfa3.git
cd pyrdfa3

• Installing the package:
~/schema_rdfa/bin/python setup.py install

• Error:
...
byte-compiling /home/dan/schema_rdfa/lib/python3.3/site-packages/pyRdfaExtras/init.py to init.cpython-33.pyc
File "/home/dan/schema_rdfa/lib/python3.3/site-packages/pyRdfaExtras/init.py", line 112
def add(self, (s,p,o)) :
^
SyntaxError: invalid syntax

It looks like Python 3 dropped support for using tuples directly in method signatures like this five years ago via PEP 3113 (http://www.python.org/dev/peps/pep-3113/) with warnings added as of Python 2.6. I expect the alternative would be something like "def add(self, triple)" and then checking to ensure that triple[0], [1], and [2] were all defined.

Looking over RDFlib itself, it seems that the API is rife with tuple unpacking behaviour :/

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http://www.ivan-herman.net

[joernhees]

@iherman i think @gromgull already explained this: in the core rdflib the setup.py does the 2to3 magic, while in this standalone it is not invoked. That's why it didn't manifest itself in rdflib core but here.

[joernhees]

i'll close this in favor of #9 for now, reopen if necessary