## Java 8 - 354 bytes Golfed version: <!-- language: lang-java --> import java.util.*;class C{static int i,j;public static void main(String[]z){boolean[]b=new boolean[256];List o=Arrays.asList("chew","swallow","vomit","complain","feedtodog","playwithfood");Runnable[]r={()->b[i]=!b[i],()->i++,()->i--,()->System.out.print(b[i]?1:0),()->j+=b[i]?1:0,()->j-=b[i]?3:0};for(;;){r[o.indexOf(z[j])].run();i=i<0|i>255?0:i;j++;}}} Somewhat ungolfed version (whitespaces and comments added): <!-- language: lang-java --> // Needed for java.util.List and java.util.Arrays. import java.util.*; class C { // Declared as static so they may be changed inside the lambdas without the compiler complaining about that. // i is the bit index and j is the instruction pointer. static int i, j; public static void main(String[] z) { // The array. boolean[] b = new boolean[256]; // Declared as a list so we can use the indexOf method further down. Screw up the generics. List o = Arrays.asList("chew", "swallow", "vomit", "complain", "feedtodog", "playwithfood"); // An array of lambdas. Runnable[] r = { () -> b[i] = !b[i], // chew () -> i++, // swallow () -> i--, // vomit () -> System.out.print(b[i] ? 1 : 0), // complain () -> j += b[i] ? 1 : 0, // feedtodog. It is 1 and 0 instead of 2 and 1 due to the j++ down there. () -> j -= b[i] ? 3 : 0 // playwithfood. It is -3 and 0 instead of -2 and +1 due to the j++ down there. }; // This is the interpreter itself. Runs forever (or until an exception is raised). for (;;) { // Fetch an instruction and runs it. Throws an exception on unknown or mistyped instructions. r[o.indexOf(z[j])].run(); // Resets the bit index if out of range. i = i < 0 | i > 255 ? 0 : i; // Next instruction. No special treatment for branching needed because the branching instructions already considers this. j++; } } } This is a quick and dirty version that I made. It could probably be somewhat shorter, but I done this in just a few minutes. We surely should have testcases. I am not sure if there is some bug hiding out there. Anyway I run it with that (input is given as command line arguments): <!-- language: lang-none --> chew complain swallow chew complain swallow chew complain swallow complain And here is the output: 1110 Exception in thread "main" java.lang.ArrayIndexOutOfBoundsException: 10 at C.main(C.java:1) The `ArrayIndexOutOfBoundsException` is the standard way to finish the program, it is not a bug!