8 lines
207 B
Racket
8 lines
207 B
Racket
#lang datalog
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% path test from Chen & Warren
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edge(a, b). edge(b, c). edge(c, d). edge(d, a).
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path(X, Y) :- edge(X, Y).
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path(X, Y) :- edge(X, Z), path(Z, Y).
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path(X, Y) :- path(X, Z), edge(Z, Y).
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path(X, Y)?
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