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Goals

Goals (or queries) are formed using the following syntax:

$\displaystyle G$ $\displaystyle ::=$ $\displaystyle \mathsf{true} \mid A \mid t_1 \mathrel{\mathsf{is}} t_2 \mid t_1 = t_2 \mid \mathsf{n} \mathrel\char93 t$  
  $\displaystyle \mid$ $\displaystyle G_1 , G_2 \mid G_1 ; G_2 \mid {!} \mid G_1 \to G_2\vert G_3 \mid \mathsf{not}(G)$  

They include the trivial goal $ \mathsf{true}$, atomic predicates, evaluation operator $ \mathsf{is}$, unification $ =$, freshness $ \mathrel\char93 $, conjunction $ G,G$, disjunction $ G;G$, ``cut'' $ !$, if-then-else $ G_1 \to G_2 \mid G_3$, and negation $ \mathsf{not}(G)$.


James Cheney 2003-10-23