Re: [eclipse-clp-users] Getting legaly named variables / Unifiying Term Lists

From: Christian Wirth <tyrion_at_...215...>
Date: Thu, 11 Feb 2010 15:10:21 +0100
I think i solved it ... after going through the API the 100th time i 
found "merge" that works like union without unification ....

Christian Wirth schrieb:
> Ok, sorry for writing not more, but thought yesterday i have now 
> completed the current feature (except the small problem) ... but after 
> sleeping a night over it, i think i must possibly change something 
> somewhere else.
>
> Here now the complete problem:
>
> I have term's in CNF that i split up according to some predicates. The 
> splitted clauses are added to lists, but this must happen without prolog 
> trying to bind the variables.
> So i decided to convert the terms into strings bevor adding, to prevent 
> the binding. As several times mentioned, i need to preserve variable 
> names/numbers exactly.
> term_to_bytes preserves variable names but not numbers. term_string does 
> preserve the numbers but not the names.
> In theory term_to_bytes should also perserve the numbers, but it doesn't 
> work for me ...
> I so i used set_var_name to name all variables and use term_to_bytes.
>
> I can't reproduce the problem without the complete programm .. i assume 
> it hase something to do when the variables are getting bound, but here 
> is the relevant code at least:
>
> myCall(TermA,S1),myCall(TermB,S2),union(S1,S2,S)
>
> myCall(Term,State) :- 
> conjunctionlist(Term,List,StringState),maplist(bytes_to_term,StringState,State).
>
> %Splits state dependent (d_true) from other facts. Temporary conversion 
> to string to prevent prolog from solving
> conjunctionlist((A,B),Independent,Dependent) :- 
> conjunctionlist(A,IndependentA,DependentA),conjunctionlist(B,IndependentB,DependentB),union(IndependentA,IndependentB,Independent),union(DependentA,DependentB,Dependent),!.
> conjunctionlist((A;B),Independent,Dependent) :- 
> conjunctionlist(A,Independent,Dependent).
> conjunctionlist((A;B),Independent,Dependent) :- 
> conjunctionlist(B,Independent,Dependent),!.
> conjunctionlist(\+(d_true(Arg,_)),[],[SArg]) :-  preserve(\+(Arg),SArg),!.
> conjunctionlist(d_true(Arg,_),[],[SArg]) :- preserve(Arg,SArg),!.
> conjunctionlist(Term,[Term],[]).
>
> preserve(Term,String) :- (foreacharg(X,Term) do 
> ((var(X),set_var_name(X,'Var'));true)),term_to_bytes(Term,String).
>
>
> Kish Shen schrieb:
>   
>> Christian Wirth wrote:
>>     
>>> i'm currenlty using set_var_name in my programm to get lists like this:
>>>
>>> List=[pred(Var#1,Var#2)].
>>>
>>>       
>> I am not quite sure what you mean by "get lists like this". 
>> lib(var_name) is designed purely to allow unique names for variables 
>> when they are printed. You should not use them in any other way.
>>
>>     
>>> i have now a second list
>>>
>>> List2=[pred(Var#3,Var#4),pred2(Var#3,Var#4)]
>>>
>>> and then i call union(List,List2,Result) and Result becomes 
>>> [pred(Var#1,Var#2),pred2(Var#3,Var#4)], but i need 
>>> [pred(Var#1,Var#2),pred2(Var#1,Var#2)]
>>>
>>>       
>> I am not sure I understand how you got this. What exactly did you write?
>>
>> I just tried:
>>
>> set_var_name_counter('Var', 1),set_var_name([W,X,Y,Z], 'Var'),
>> L1 = [pred(W,X)], L2 = [pred(Y,Z),pred2(Y,Z)], union(L1,L2, L)
>>
>> and here is the the result:
>>
>> W = Var#1
>> X = Var#2
>> Y = Var#1
>> Z = Var#2
>> L1 = [pred(Var#1, Var#2)]
>> L2 = [pred(Var#1, Var#2), pred2(Var#1, Var#2)]
>> L = [pred(Var#1, Var#2), pred2(Var#1, Var#2)]
>>
>>     
>>> this should work, but it only does with "normal" variable names like 
>>> Var .. not with the # in between.
>>>       
>> I don't understand this at all. Using lib(var_name) should not have 
>> any effect on how the program behave, it only affects the way a 
>> variable's name is printed. What do you mean it does not work with # 
>> in between?
>>
>>     
>>> Now i have to choices changing set_var_name to create legal names, 
>>> but the function is build in ??
>>> .. or to get union to somehow correctly consider all named variables ?
>>>       
>> Are you somehow thinking of usng these names in your own source code? 
>> The source code names have nothing to do with the names lib(var_name) 
>> produces -- the non-legal names is there to prevent you confusing 
>> names you write in your source from the names printed using 
>> lib(var_name).
>>
>> Cheers,
>>
>> Kish
>>     
>
>
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Received on Thu Feb 11 2010 - 14:10:32 CET

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