An Update on Deductive Synthesis and Repair in the Leon Tool

Abstract

We report our progress in scaling deductive synthesis and repair of recursive functional Scala programs in the Leon tool. We describe new techniques, including a more precise mechanism for encoding the space of meaningful candidate programs. Our techniques increase the scope of synthesis by expanding the space of programs we can synthesize and by reducing the synthesis time in many cases. As a new example, we present a run-length encoding function for a list of values, which Leon can now automatically synthesize from specification consisting of the decoding function and the local minimality property of the encoded value.Comment: In Proceedings SYNT 2016, arXiv:1611.0717

Synbit: synthesizing bidirectional programs using unidirectional sketches

“…Alternatively, Smith and Albarghouthi (2019) generate only programs in a specific normal form, where term rewriting is used to transform a program into its normal form. In (Koukoutos et al 2016), Koukoutos et al make use of attribute grammars to only produce certain types of expressions in their normal form, thus skipping other expressions that are syntactically different, yet semantically equivalent. In our work, we found that the lightweight heuristics described in Section 3.6 worked well.…”

On Repair with Probabilistic Attribute Grammars

“…The approach of annotating types with attributes has already been introduced in [20], but there the attributes and their interpretation were predefined. Here we allow the user to provide their own wrapper classes.…”

“…In case the user does not want to manually implement a custom attribute grammar as above, they can reside to a set of default built-in axioms described in [20]. In case of the default grammars, those axioms are automatically applied to each combination of nonterminal and production rule.…”

“…it should be treated as neutral element of addition), whereas @tag("commut") specifies foo as a commutative operation. These rules will undergo a set of predetermined optimizations described in [20].…”

“…Program synthesis has attracted significant attention as a promising and ambitious approach to improve software development productivity [21,33,1,10,30,15,12,13,23,11,26,18,20]. Among possibly deployment scenarios of synthesis is program repair, in which a tool localized an error repairs the program by synthesizing an alternative code fragment [24,17].…”