Kevlox. Parser+Compiler+VM for the Lox programming language. Customized by me, Kevin.

Open code.txt and insert the following code snippet:

fun fib(n) {
  if (n < 2) return n;
  return fib(n - 2) + fib(n - 1);
}

var start = clock();
print "Fib35 result:";
print fib(35);
print "Time (s):";
print clock() - start;

To compile and run the code, simply execute the following command in your terminal:

make all

This will process the code, calculate the 35th Fibonacci number, and display both the result and the execution time.

• source code scanner/lexer
• single pass compiler
• stack-based bytecode VM
• debugging disassembler
• functions are first-class citizens

NOTES:

• binary operators are infix
• unary are prefix
• A compiler has roughly two jobs. Many languages split the two roles into two separate passes
  • It parses the user’s source code to understand what it means
  • Then it takes that knowledge and outputs low-level instructions that produce the same semantics
  • A parser produces an AST and then a code generator traverses the AST and outputs target code
• bytecode > syntax trees
• only supports double-precision floating point numbers
• we want to do as much work as possible during compilation to keep execution simple and fast
• preorder : "on the way down"
• postorder : "on the way back up"

TODO:

• lambda as λ
• let instead of var
• call it bub lang...or lang lang?

bug:

• print 0 or 1 returns 0
  • resolve 0 as false and 1 as true
• #define DEBUG_PRINT_CODE segfault
• #define DEBUG_STRESS_GC segfault