Filtered Iterators For Safe and Robust Programs in RIFL

Abstract

We present a new language construct, filtered iterators, for safe and robust input processing. Filtered iterators are designed to eliminate many common input-processing errors while enabling robust continued execution. The design is inspired by (a) observed common input-processing errors and (b) continued execution strategies that are implemented by developers fixing input validation errors. Filtered iterators decompose inputs into input units, atomically and automatically discarding units that trigger errors. Statistically significant results from a developer study highlight the difficulties that developers encounter when developing input-processing code using standard language constructs. These results also demonstrate the effectiveness of filtered iterators in eliminating many of these difficulties and enabling developers to produce safe and robust input-processing code.