What steps will reproduce the problem? 1. Use a slice in a production rule, eg:

def p_toplevel(p): """ toplevel : alpha beta gamma TOKEN delta """ p[0] = p[1:4] + p[5:]

What is the expected output? What do you see instead? Expected: p[0] is a list of the nonterminals alpha, beta, gamma, and delta. Got: File "/usr/lib/python3.1/site-packages/ply/yacc.py", line 198, in getitem if n >= 0: return self.slice[n].value TypeError: unorderable types: slice() >= int()

What version of the product are you using? On what operating system?

This is python 3.1, but this has been true since python 3.0: http://docs.python.org/py3k/whatsnew/3.0.html#operators-and-special-methods

Namely, instead of getslice being called as it was in python 2.x, getitem is called with a slice object, which is being compared with an int in YaccProduction's case. (Similarly, my testing shows that even in Python 2.7, a slice that includes a step, eg. a[1:4:2], sends a slice object to getitem instead of to getslice.)

Simple patch included (Python 2 compatible) to fix this, but I note it allows the use of negative indices in slices in a way that doesn't match how negative indexing currently works.

I ran into this problem as well, but my fix was the following (also plays nice with negative indices):

def getitem(self,n): if isinstance(n,slice): return [self[i] for i in range(*(n.indices(len(self.slice))))] else: # for integer indices, do what we used to if n >= 0: return self.slice[n].value else: return self.stack[n].value

I'm not sure if using slices is really documented in PLY, but I'll make a fix in PLY-3.5. --Dave

Thanks! That would be great :)

Our project has been using slices in ply for years, and now that I tried porting it to python3 everything broke :)

Regards,

Gašper

For what it's worth, I'm doing a bunch of compiler work with PLY right now in Python 3. I don't use slices so I haven't encountered this, but I'm hoping to put out a new PLY release sometime in the near future (4-5 weeks). If you find other bugs, please let me know.

Just wanted to chime in that I experienced this issue today with Python 3... It has been over a year since it was reported and the attached patch fixes the issue. Are there any plans to release 3.5 any time soon? If not could we get a 3.4.1 release out that includes this patch? Thanks!

I just upgraded my system and I'm running into this issue myself. Any chance we can get a new version out with the patch applied?

Anything new concerning releasing Ply 3.5 fixing this bug? Or do we have to avoid using slices in rules?

I'm pretty sure that this has already been fixed in github.