The Parser Grammar Engine (PGE, originally the Parrot Grammar Engine) is a compiler and runtime for Raku rules for the Parrot virtual machine. PGE uses these "rules" to convert a parsing expression grammar into Parrot bytecode. It is therefore compiling rules into a program, unlike most virtual machines and runtimes, which store regular expressions in a secondary internal format that is then interpreted at runtime by a regular expression engine. The rules format used by PGE can express any regular expression and most formal grammars, and as such it forms the first link in the compiler chain for all of Parrot's front-end languages.