Context Dependent Procedures and Computed Types in ✓eriFun

Second-Order Programs with Preconditions

“…We show how incompletely defined programs [19] fit into this approach (Sect. 2.3) and compare it with the original definitions described in [14,19] …”

“…The input language L of eriFun that we consider in this section roughly corresponds to the first-order fragment of ML or Haskell with strict evalua-tion [14,16]. First, we describe the syntax of first-order programs with preconditions (Sect.…”

“…Since subsequent extensions [14] of eriFun demand that ?cons(t) be verified for each selector call sel (t), where cons is the constructor that sel belongs to, such indetermined values cannot occur anymore. Therefore we simplify the semantics as in computation rule (4), which returns the fixed witness value ω τ .…”

“…By treating such procedures as procedures with implicit preconditions, we combine the advantages of [19] and [14] and get a unified view on both concepts. -We describe a method to statically analyze if preconditions are satisfied in second-order programs.…”

“…Our technique has been implemented and integrated into eriFun, a semiautomated verifier for functional programs [17,18]. eriFun's input language L [16] for functional programs allows developers to annotate procedures with preconditions [14]. eriFun generates verification conditions to verify that the precondition of each procedure call in a program is satisfied.…”