ASTLOG: a language for examining abstract syntax trees

Abstract

Syntax Trees Roger F. Crew Microsoft Research ASTLOG: A Language for Examining Abstract Syntax Trees Roger F. Crew Microsoft Research Microsoft Corporation Redmond, WA 98052 rfc@microsoft.com Abstract We desired a facility for locating#analyzing syntactic artifacts in abstract syntax trees of C#C++ programs, similar to the facility grep or awk provides for locating artifacts at the lexical level. Prolog, with its implicit pattern-matching and backtracking capabilities, is a natural choice for suchanapplication. We have developed a Prolog variant that avoids the overhead of translating the source syntactic structures into the form of a Prolog database; this is crucial to obtaining acceptable performance on large programs. An interpreter for this language has been implemented and used to #nd various kinds of syntactic bugs and other questionable constructs in real programs like Microsoft SQL server #450Klines# and Microsoft Word #2Mlines# in time comparable to the runtime of th...