Algorithmic program synthesis: introduction

Program synthesis is a process of producing an executable program from a specification. Algorithmic synthesis produces the program automatically, without an intervention from an expert. While classical compilation falls under the definition of algorithmic program synthesis, with the source program being the specification, the synthesis literature is typically concerned with producing programs that cannot be (easily) obtained with the deterministic transformations of a compiler. To this end, synthesis algorithms often perform a search, either in a space of candidate programs or in a space of transformations that might be composed to transform the specification into a desired program. In this introduction to the special journal issue, we survey the history of algorithmic program synthesis and introduce the contributed articles. We divide the field into reactive synthesis, which is concerned with automata-theoretic techniques for controllers that handle an infinite stream of requests, and functional synthesis, which produces programs consuming finite input. Contributed articles are divided analogously. We also provide pointers to synthesis work outside these categories and list many applications of synthesis.