道歉是一种艺术.ppt

FortgeschritteneProgrammierungLucDeRaedt(originalslidesbyPeterFlach)2000

Meta-Interpreter2000

Prologmeta-interpretersAmeta-interpreterforalanguageisaninterpreterforthelanguagewritteninthelanguageitself./*solve(Goal):-

GoalistruegiventhepureProlog

programdefinedbyclause/2.*/prove(true):-!.prove((A,B)):-!,

prove(A),

prove(B).prove(A):-

/*notA=true,notA=(X,Y)*/

clause(A,B),

prove(B).p.70-22000

Meta-levelvs.object-levelp(X):-q(X).q(a).clause(p(X),q(X)).clause(q(a),true).?-p(X).X=a?-prove(p(X)).X=aunificationMETA-LEVELOBJECT-LEVELKNOWLEDGEREASONINGp.712000

Meta-interpretercomputingprooftrees/*

solve(Goal,Tree):-

TreeisaprooftreeforGoalgiven

theprogramdefinedbyclause/2.

*/solve(true,true):-!.solve((A,B),(ProofA,ProofB)):-

!,

solve(A,ProofA),

solve(B,ProofB).

solve(A,(A:-builtin)):-

predicate_property(A,built_in),

!,

call(A).

solve(A,(A:-Proof)):-

clause(A,B),

solve(B,Proof).2000

Meta-interpretercomputingprooftrees

:-dynamicdaughter/2,father/2,son/2,

male/1,female/1.

father(abraham,isaac).

male(isaac).

father(haran,lot).male(lot).

father(haran,milcah).female(milcah).

father(haran,yiscah).female(yiscah).

daughter(X,Y):-father(Y,X),female(X).

son(X,Y):-father(Y,X),male(X).

?-solve(son(lot,X),P).

P=(son(lot,haran):-(father(haran,lot):-true),(male(lot):-true)),

X=haran?2000

Meta-interpreterwithdepth-limit

/*

solve(Goal,MaxDepth,Tree):-

TreeisaprooftreeofMaxDepthforGoal

giventheprogramdefinedbyclause/2.

*/

solve(true,D,true):-D0,

!.

solve((A,B),D,(ProofA,ProofB)):-

D0,

!,

solve(A,D,ProofA),

solve(B,D,ProofB).

solve(A,D,(A:-Proof)):-

D0,

clause(A,B),

NewDisD-1,

solve(B,NewD,Proof).

2000

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