decrypt(tab;kval)
== kval/k,x.
== if isl(st-lookup(tab;x))
== if outl(st-lookup(tab;x))/key,data. if st-key-match(tab;key;k) inl(data) else inr() fi
== else inr() fi 

latex

Definitions	isl(x), A/x,y. B(x;y), outl(x), st-lookup(tab;x), if b t else f fi, st-key-match(tab;k1;k2), inl(x), inr(x),
FDL editor aliases	st-decrypt