# OT: Perl parser **URL:** \ **Category:** Ruby\ **Created:** [July 28, 2006, 6:46pm UTC](https://www.ruby-forum.com/t/ot-perl-parser/100392 "2006-07-28T18:46:36Z")\ **Posts on this page:** 1\ **Page:** 1
**Author:** ![cpeterson](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/c/58f4c7/32.png) [@cpeterson](https://www.ruby-forum.com/u/cpeterson)\ **Post date:** [July 28, 2006, 6:46pm UTC](https://www.ruby-forum.com/t/ot-perl-parser/100392/1 "2006-07-28T18:46:36Z")
Since it came up earlier and was the subject of some discussion, I figured I’d add to the confusion^Wcommon body of knowledge regarding Perl’s compiler/interpreter status: Perl does not compile to bytecode and does not use a VM, as implied in some previous comparisons to Java. The JVM is, in some respects, essentially an extremely limited form of operating system emulator, where the OS is specifically designed for the sole purpose of running Java bytecode-compiled programs. Java source is compiled to bytecode form (JVM-native code) and stored in that form. Then, when you want to execute the program, you turn on your virtual computer running your virtual Java OS and run your program there. Perl, meanwhile, compiles to parse trees, which are then interpreted in a mostly-traditional programming language interpreter model of execution, with no VM processes running. This may not immediately strike one as being particularly different, but it should be noted that classic interpretation is a line-by-line execution of instructions (which are in this case harvested from a parse tree) within an operating environment, while a VM is itself an operating environment that happens to require an enclosing operating environment. Each approach has its own positive and negative performance characteristics. Now that I consider the matter a bit more, I’m amused to consider that the compilation phase for Perl results in something strangely akin to compilation-to-Lisp (Lisp being, in some respects, nothing but human-readable parse trees).