francia@nmt.edu (Guillermo A. Francia) (02/21/91)
Perhaps somebody out there can enlighten me on the following issues about logic programming: 1) Given a logic program (assuming the absence of aliasing and cuts), is it possible to statically infer on what particular clause a variable can get instantiated? If this is undecidable, is there any safe approximation to it? 2) Given that a variable instantiation can be statically inferred, is it possible to determine all the possible instantiation point of a variable in the program? I will appreciate any help that I can get. Thanks in advance. -- -------------------------------------------------------------------- francia@jupiter.nmt.edu Guillermo A. Francia III P.O. Box 2335 CS francia@minos.nmt.edu New Mexico Tech
jha@cs.ed.ac.uk (Jamie Andrews) (02/25/91)
In article <1991Feb20.231413.12025@nmt.edu> francia@nmt.edu (Guillermo A. Francia) writes: >1) Given a logic program (assuming the absence of aliasing and cuts), >is it possible to statically infer on what >particular clause a variable can get instantiated? If this is >undecidable, is there any safe approximation to it? I find your question difficult to understand; this may mean that I'm just dense about this, or it may mean that it's phrased a bit vaguely. (The lack of response on this newsgroup may suggest the second explanation.) Do you mean "given a logic program and a query, is it possible to statically infer the clause in the program which will effect the instantiation of a given variable in the query"? Also, assuming no cuts seems reasonable, but what do you mean by "assuming no aliasing"? No variable used in more than one place in the query? In the program? (The latter would be a bit unreasonable, but the former wouldn't be much of a restriction in general without the latter...) >2) Given that a variable instantiation can be statically inferred, is it >possible to determine all the possible instantiation point of a variable in >the program? This might be clarified by a clarification to (1)... >francia@jupiter.nmt.edu Guillermo A. Francia III --Jamie. jha@cs.ed.ac.uk "'He acts crazy, I guess. We all act crazy. I guess God acts crazy.' Etc."