On 10/12/2016 06:55 PM, Linas Vepstas wrote:
Well, yes, but Nil,, look at the core issue: the variable X in the Implication link is bound, but the unit test is pretending that its free. My question is: are you *sure* you really want the implicationLink to inherit from Scope Link (and thus, always bind it's variables)?
X is supposed to be free in the ImplicationLink, bound to the PutLink. Yes I am sure I want it free in the ImplicationLink. Having ImplicationLink inherit Scope should not prevent that. The syntax itself is ambiguity free, if there are ambiguities in the code it's a bug and it should be fixed.
Again, I'm happy to fix anything related to that once the issue reappears. Nil
--linas On Wed, Oct 12, 2016 at 10:39 AM, Nil Geisweiller <ngeis...@googlemail.com <mailto:ngeis...@googlemail.com>> wrote: OK, when they fail again I guess you might feel free to push to the master, as we're apparently using as a dev branch, and then I'll fix that. Nil On 10/12/2016 06:17 PM, Linas Vepstas wrote: No, actually, I worked around that. The only reason that PutLinkUTest currently passes is because PutLink fails to treat ScopeLinks correctly. When that gets fixed, the unit test will fail ... the issue remains the same. --linas On Tue, Oct 11, 2016 at 11:57 PM, Nil Geisweiller <ngeis...@googlemail.com <mailto:ngeis...@googlemail.com> <mailto:ngeis...@googlemail.com <mailto:ngeis...@googlemail.com>>> wrote: Are these unit tests still failing? Nil On 10/11/2016 08:36 PM, Linas Vepstas wrote: 47 unit tests fail ... I'm not sure if they all fail for the same reason, though. For example PutLink (PutLink (LambdaLink (VariableList (TypedVariableLink (VariableNode "$X") (TypeNode "PredicateNode") ) (TypedVariableLink (VariableNode "$Y") (TypeNode "PredicateNode") ) ) (AndLink (EvaluationLink (PredicateNode "acquainted") (ListLink (VariableNode "$X") (VariableNode "$Y") ) ) (ImplicationLink (VariableNode "$X") ; this is alpha-converted to $foo1233 (PredicateNode "is-human") ) (ImplicationLink (VariableNode "$X") ; this is alpha-converted to $bar456 (PredicateNode "is-human") ) ) ) (ListLink (PredicateNode "is-Self") (PredicateNode "is-Bob") ) ) So, because the implication link is scoped, the result of the variable substitution is (AndLink (ImplicationLink (VariableNode "$foo123") (PredicateNode "is-human") ) (ImplicationLink (VariableNode "$bar456") (PredicateNode "is-human") ) (EvaluationLink (PredicateNode "acquainted") (ListLink (PredicateNode "is-Self") (PredicateNode "is-Bob") ) ) ) which is not what the unit test expects. The problem with using either ScopeLink or LambdaLink is that it becomes impossible to have a stable variable name -- it can be alpha-converted to anything, so any algo that depends on having a fixed, well-known variable name will fail. In this case -- I am not sure -- if you want ImplicationLink to be scoped, then the unit test is wrong. But is the unit test is right, then implication link must not be scoped. I cannot tell which one is wanted. --linas On Tue, Oct 11, 2016 at 12:12 PM, Nil Geisweiller <ngeis...@googlemail.com <mailto:ngeis...@googlemail.com> <mailto:ngeis...@googlemail.com <mailto:ngeis...@googlemail.com>> <mailto:ngeis...@googlemail.com <mailto:ngeis...@googlemail.com> <mailto:ngeis...@googlemail.com <mailto:ngeis...@googlemail.com>>>> wrote: Linas, I don't have time to get into that right now. If you can point to where exactly it breaks (like a unit test on your branch) it would help. In any case I look carefully into that and reply tomorrow. Nil On 10/11/2016 06:55 PM, Linas Vepstas wrote: You made it inherit from ScopeLink, thus making the variables in it implicitly scoped. Then you added the file ImplicationLink.cc, and have notes in there, complaining about how variables are implcitly scoped. The wiki page for it, http://wiki.opencog.org/w/ImplicationLink <http://wiki.opencog.org/w/ImplicationLink> <http://wiki.opencog.org/w/ImplicationLink <http://wiki.opencog.org/w/ImplicationLink>> <http://wiki.opencog.org/w/ImplicationLink <http://wiki.opencog.org/w/ImplicationLink> <http://wiki.opencog.org/w/ImplicationLink <http://wiki.opencog.org/w/ImplicationLink>>> still says things that are wrong (re alpha conversion -- each lambda gets alpha converted, so the "sugar syntax" section cannot possibly be right). I'm asking, because I'm trying to fix #910 by doing the alpha conversion correctly, and the result of the fix is that unit tests with implication links in them now fail. The whole thing smells bad. Either ImplicationLinks do inherit from ScopeLink, in which case, there should be no complaints about how the ScopeLink works: it does the right thing. If you don't like what the scopeLink does, then ImplicationLinks should NOT inherit from it ... In either case, the wiki page needs fixing, because the alpha conversion conversation we had recently renders that page incoherent. I don't really care, one way or the other, but I do need to understand the intended design well enough to be able to fix bugs, and right now, I don't understand what ImplicationLink is, or how its supposed to work. --linas
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