vars() gives me an error message

[Jim Mooney]

When I try to use vars() to see local variables I get this pink error message that goes on about "crystals" What's that about?

[Dima Pasechnik]

Indeed, it appears that vars() is broken, and has been broken since Sage 7.5, at least.

Running

sage: vars()

ends with

---------------------------------------------------------------------------

TypeError                                 Traceback (most recent call last)

<ipython-input-7-a05597ed1f36> in <module>()

----> 1 vvv

/home/dima/Sage/sage-dev/local/lib/python2.7/site-packages/IPython/core/displayhook.pyc in __call__(self, result)

    244             self.start_displayhook()

    245             self.write_output_prompt()

--> 246             format_dict, md_dict = self.compute_format_data(result)

    247             self.update_user_ns(result)

    248             self.fill_exec_result(result)

/home/dima/Sage/sage-dev/local/lib/python2.7/site-packages/IPython/core/displayhook.pyc in compute_format_data(self, result)

    148 

    149         """

--> 150         return self.shell.display_formatter.format(result)

    151 

    152     # This can be set to True by the write_output_prompt method in a subclass

/home/dima/Sage/sage-dev/local/lib/python2.7/site-packages/sage/repl/display/formatter.pyc in format(self, obj, include, exclude)

    158         # First, use Sage rich output if there is any

    159         PLAIN_TEXT = u'text/plain'

--> 160         sage_format, sage_metadata = self.dm.displayhook(obj)

    161         assert PLAIN_TEXT in sage_format, 'plain text is always present'

    162         if sage_format.keys() != [PLAIN_TEXT]:

TypeError: 'NoneType' object is not iterable

[John H Palmieri]

I think it's a (pretty?) printing problem. For me, running

    sage: a = vars()

works without error, but then

   sage: a

gives the error. Same thing happens with locals().

--
John

[Dima Pasechnik]

no, it's more serious, perhaps something to do with lazy imports?

sage: v=vars()

sage: v['complete_sandpile']

<repr(<sage.misc.lazy_import.LazyImport at 0x7f2cd6528d00>) failed: AttributeError: 'module' object has no attribute 'complete_sandpile'>

(I found the value of the guilty key by running

sage: for k in v.keys(): v[k]==None;

until it breaks)

(same value on Sage 7.5 and on the latest beta)

Dima

[Dima Pasechnik]

In fact, complete_sandpile has been removed, but the lazy import for it is still there.

So this has to be fixed. I will open a ticket.

[Dima Pasechnik]

this is now #22933, ready for review.

Note that it's not a complete fix; 

sage: vars()

still fails

sage: v=vars()

sage: for k in v.keys(): print v[k]

works with the ticket branch.

[John H Palmieri]

See #22941 for a separate approach (independent of #22933, each ticket fixes a different problem).

  John

[Jim Mooney]

I just wanted my own variables so this works. (I modified something I found on the web to delete all other values:

G = globals()

for k in G:

    if type(G[k]) == sage.symbolic.expression.Expression:

        if G[k] not in [golden_ratio, NaN, I, log2,pi,catalan,euler_gamma,twinprime, khinchin, glaisher, mertens]:

            print k