Digging for fold: synthesis-aided API discovery for Haskell

Abstract

We present Hoogle+, a web-based API discovery tool for Haskell. A Hoogle+ user can specify a programming task using either a type, a set of input-output tests, or both. Given a specification, the tool returns a list of matching programs composed from functions in popular Haskell libraries, and annotated with automatically-generated examples of their behavior. These features of Hoogle+ are powered by three novel techniques. First, to enable efficient type-directed synthesis from tests only, we develop an algorithm that infers likely type specifications from tests . Second, to return high-quality programs even with ambiguous specifications, we develop a technique that automatically eliminates meaningless and repetitive synthesis results . Finally, we show how to extend this elimination technique to automatically generate informative inputs that can be used to demonstrate program behavior to the user. To evaluate the effectiveness of Hoogle+ compared with traditional API search techniques, we perform a user study with 30 participants of varying Haskell proficiency. The study shows that programmers equipped with Hoogle+ generally solve tasks faster and were able to solve 50% more tasks overall.

ArCode: A Tool for Supporting Comprehension and Implementation of Architectural Concerns

“…ALPS [45] leverages a syntax-guided approach to learn from examples of Datalog programs on how to generate a sequence of Datalog rules for a given task. Hoogle+ [46] creates a code snippet from Haskell popular libraries based on the specified signature of the function and a set of input/output examples. In another work, SyRust [47] relies on the Rust language ownership type system to create a program from a sequence of Rust language API calls.…”