Re: [racket-users] Apparent Datalog error?

On 1/31/2018 2:51 PM, Matthias Felleisen wrote: > On Jan 31, 2018, at 2:15 PM, George Neuner wrote: > > > On 1/31/2018 2:10 PM, Sam Caldwell wrote: >> Your definition of `ancestor` is one or two steps of parentage: >> >> > ancestor(A, B) :- parent(A, B). >> >

Re: [racket-users] Apparent Datalog error?

> On Jan 31, 2018, at 2:15 PM, George Neuner wrote: > > > On 1/31/2018 2:10 PM, Sam Caldwell wrote: >> Your definition of `ancestor` is one or two steps of parentage: >> >> > ancestor(A, B) :- parent(A, B). >> > ancestor(A, B) :- >> parent(A, C), >> parent(C,

Re: [racket-users] Apparent Datalog error?

On 1/31/2018 2:10 PM, Sam Caldwell wrote: Your definition of `ancestor` is one or two steps of parentage: > ancestor(A, B) :- parent(A, B). > ancestor(A, B) :-   parent(A, C),   parent(C, B). I suspect you want one of those lines to appeal to the `ancestor` relation to allow longer

Re: [racket-users] Apparent Datalog error?

Your definition of `ancestor` is one or two steps of parentage: > ancestor(A, B) :- parent(A, B). > ancestor(A, B) :- parent(A, C), parent(C, B). I suspect you want one of those lines to appeal to the `ancestor` relation to allow longer chains. - Sam Caldwell On Wed, Jan 31, 2018 at 1:53 PM,

[racket-users] Apparent Datalog error?

Walking through the datalog tutorial I got the following transcript: Welcome to DrRacket, version 6.12 [3m]. Language: datalog, with debugging; memory limit: 512 MB. > parent(john, douglas). > parent(john, douglas)? parent(john, douglas). > parent(john, evlyn)? > parent(bob, john). > parent(A,