interpreter

In Steve Yegge's review of Design Patterns , he calls the Interpreter Pattern an "in-joke". He goes on to talk about how the perception of compilers have changed, yet how interpreted languages are still s*** on, although I can't see how this ties into the pattern. Anyone want to enlighten this ignorant student? vava That was irony :) Everybody loves interpreted languages nowadays but 10 years earlier people just thought they are too slow for anything practical. Much like today most of people thinks about static vs. dynamic typing. The INTERPRETER pattern sucks because it's a codification of

I have an app which I'd like to make extensible by letting users define classes in Groovy, eventually implementing some interfaces. The key aspect is that it should be interpreted/compiled at runtime. I.e. I need my app to take the .groovy and compile it. Doing it during boot is ok. Then, of course, my app should be able to instantiate that class. I see two solutions: 1) Compile while the app runs, put the classes somewhere on classpath, and then just load the classes, pretending they were always there. 2) Some smarter way - calling a compiler API and some classloading magic to let my system

How does a virtual machine generate native machine code on the fly and execute it? Assuming you can figure out what are the native machine op-codes you want to emit, how do you go about actually running it? Is it something as hacky as mapping the mnemonic instructions to binary codes, stuffing it into an char* pointer and casting it as a function and executing? Or would you generate a temporary shared library (.dll or .so or whatever) and load it into memory using standard functions like LoadLibrary ? You can just make the program counter point to the code you want to execute. Remember that

my scala program is using the compiler interface from scala.tools.nsc.interpreter.IMain. When I am compiling with scalac, everything works as expected. But when I compile with sbt it still compiles, but on execution it throws the following error message in the call of the interpret-method from the IMain instance: Failed to initialize compiler: object scala not found. ** Note that as of 2.8 scala does not assume use of the java classpath. ** For the old behavior pass -usejavacp to scala, or if using a Settings ** object programatically, settings.usejavacp.value = true. If I use settings

Is it possible to access the AST of the v8 engine, for a given JavaScript code? I'm working on a JavaScript Static Analyzer using V8 engine. This is pretty old but maybe the answer helps someone stumbling upon this. The answer is yes, assuming you are willing to modify V8 and compile your own version of it. If so, then in compiler.cc you find a spot where MakeCode is called throughout MakeFunctionInfo which transforms the AST that is stored in the passed in CompilationInfo object into native code. You need to write a class that inherits from AstVisitor then you can inspect the AST by inserting

I have written a simple brainfuck interpreter in MATLAB script language. It is fed random bf programs to execute (as part of a genetic algorithm project). The problem I face is, the program turns out to have an infinite loop in a sizeable number of cases, and hence the GA gets stuck at the point. So, I need a mechanism to detect infinite loops and avoid executing that code in bf. One obvious (trivial) case is when I have [] I can detect this and refuse to run that program. For the non-trivial cases, I figured out that the basic idea is: to determine how one iteration of the loop changes the