There are many tools that help programmers find code fragments, but most are inexpressive and rely on static information. We present a new technique for synthesizing code that is dynamic (giving accurate results and allowing programmers to reason about concrete executions), easy-to-use (supporting a wide range of correctness specifications), and interactive (allowing users to refine the candidate code snippets). Our implementation, which we call CodeHint, generates and evaluates code at runtime and hence can synthesize real-world Java code that involves I/O, reflection, native calls, and other advanced language features. We have evaluated CodeHint in two user studies and show that its algorithms are efficient and that it improves programmer productivity by more than a factor of two.

No abstract

We empirically investigate whether advertisers are maximizing their return on investment (ROI) across multiple keywords in sponsored search auctions. Because testing for ROI maximization relies on knowledge of advertisers' private true values per click, we instead use necessary (although not sufficient) conditions for ROI maximizing behavior that rely only on advertisers' bids. We classify advertisers based on the extent to which they satisfy the test conditions. Our results indicate that a large fraction of advertisers in the Yahoo Webscope first price data set may be following ROIbased strategies.

No abstract

Abstract. We address the problem of writing compilers targeting complex execution environments, such as computer clusters composed of machines with multi-core CPUs. To that end we introduce partial compilers. These compilers can pass sub-programs to several child (partial) compilers, combining the code generated by their children to generate the final target code. We define a set of high-level polymorphic operations manipulating both compilers and partial compilers as first-class values. These mechanisms provide a software architecture for modular compiler construction. This allows the building of a forest of compilers, providing a structured treatment of multistage compilers.