TouchCost: Cost analysis of TouchDevelop scripts

Abstract

TouchDevelop is a novel programming environment and language for mobile devices. These applications are typically developed by non-expert users, rather small, and published on the cloud. In this paper, we introduce TouchCost a new static analysis that infers the cost of loops in TouchDevelop programs. TouchCost (i) infers numerical invariants through an existing generic analyzer, (ii) extracts cost relation systems, and (iii) solves them using an existing upper bound solver. TouchCost has been applied to all TouchDevelop scripts that are currently published on the cloud. Experimental results show that this tool is both scalable and precise. Studying the outputs of TouchCost we glimpse two major applications: (i) establishing at runtime the cost of a loop, and in case move its execution, and (ii) helping non-expert developers to debug their programs. © 2014 Springer-Verlag.