Refactored stock buying/selling code into its own file. Refactored WorkerScript & NetscriptEnvironment into their own Typescript classes. Refactored a ton of code to remove circular dependencies

src/Netscript/Environment.ts

@@ -0,0 +1,72 @@
+/**
+ * The environment in which a script runs. The environment holds
+ * Netscript functions and arguments for that script.
+ */
+import { IMap } from "../types";
+
+export class Environment {
+    /**
+     * Parent environment. Used to implement "scope"
+     */
+    parent: Environment | null = null;
+
+    /**
+     * Whether or not the script that uses this Environment should stop running
+     */
+    stopFlag: boolean = false;
+
+    /**
+     * Environment variables (currently only Netscript functions)
+     */
+    vars: IMap<any> = {};
+
+    constructor(parent: Environment | null) {
+        if (parent instanceof Environment) {
+            this.vars = Object.assign({}, parent.vars);
+        }
+
+        this.parent = parent;
+    }
+
+    /**
+     * Finds the scope where the variable with the given name is defined
+     */
+    lookup(name: string): Environment | null {
+        let scope: Environment | null = this;
+        while (scope) {
+            if (Object.prototype.hasOwnProperty.call(scope.vars, name)) {
+                return scope;
+            }
+            scope = scope.parent;
+        }
+
+        return null;
+    }
+
+	//Get the current value of a variable
+    get(name: string): any {
+        if (name in this.vars) {
+            return this.vars[name];
+        }
+
+        throw new Error(`Undefined variable ${name}`);
+    }
+
+	//Sets the value of a variable in any scope
+    set(name: string, value: any) {
+        var scope = this.lookup(name);
+
+        //If scope has a value, then this variable is already set in a higher scope, so
+        //set is there. Otherwise, create a new variable in the local scope
+        if (scope !== null) {
+            return scope.vars[name] = value;
+        } else {
+            return this.vars[name] = value;
+        }
+    }
+
+	//Creates (or overwrites) a variable in the current scope
+    def(name: string, value: any) {
+        return this.vars[name] = value;
+    }
+}