| buf = mk(mkarray(2)[0, a][1, b][0, c], 2, 0, 1) ⊦ ⟪a0 := a, ar := buf .data, i := buf .first⟫ ⟪if 0 ≤ i ∧ i < n→i(# ar) then a0 := ar[i→n(i)] else abort⟫ ⟪buf := buf .first:= ((buf .first + 1) % buf .size) ; buf := buf .len:= (buf .len - 1)⟫ ⟪assert#(a0 = c)⟫ true |
buf = mk(mkarray(2)[0, a][1, b][0, c], 2, 0, 1), a1 = a ∧ ar0 = buf .data ∧ i0 = buf .first ⊦ ⟪if 0 ≤ i0 ∧ i0 < n→i(# ar0) then a1 := ar0[i→n(i0)] else abort⟫ ⟪buf := buf .first:= ((buf .first + 1) % buf .size) ; buf := buf .len:= (buf .len - 1)⟫ ⟪assert#(a1 = c)⟫ true
[[CONCRETESIMPRULES : ()]]