Add some advent of code testing and some more modules

adventofcode/advent01-1.mc

+; Requires the input for Advent of Code(http://adventofcode.com/) Day 1
+(log result)
+(include str fs)
+(assign input (fs::readIn "advent.txt"))
+(assign i 0)
+(assign result 0)
+(repeat (str::length input)
+  (assign current (str::charAtIndex input i))
+  (if (eq current "(") (assign result (add result 1)))
+  (if (eq current ")") (assign result (subtract result 1)))
+  (assign i (add i 1))
+)
+(log result)

libjs/fs.js

+var fs = require("fs")
+
+const builtins = {
+  readIn: function (path) {
+    let str = fs.readFileSync(path.value, { encoding: 'utf-8' })
+    return {
+      value: str
+    }
+  }
+}
+
+const my_handler = {
+  get: function (target, prop) {
+    let methods = Object.keys(builtins)
+    if (methods.includes(prop)) {
+      return builtins[prop]
+    } else {
+      console.error("Undefined function call! No such function: ", prop)
+    }
+  }, 
+}
+
+const proxy_obj = new Proxy({}, my_handler)
+let _
+
+module.exports = function (self) {
+  _ = self
+  return proxy_obj
+}

libjs/str.js

     return {
       value: str
     }
+  },
+  length: function (str) {
+    return {
+      value: str.value.length
+    }
+  }, 
+  charAtIndex: function (str, i) {
+    return {
+      value: str.value.charAt(i.value)
+    }
   }
 }