Add a mechanism to enable additional (experimental) features and start with sign extension operations; Hashing experimentation

src/index.ts

@@ -6,7 +6,8 @@
 import {
   Compiler,
   Options,
-  Target
+  Target,
+  Feature
 } from "./compiler";
 
 import {
@@ -129,6 +130,14 @@ export function setGlobalAlias(options: Options, name: string, alias: string): v
   globalAliases.set(name, alias);
 }
 
+/** Sign extension operations. */
+export const FEATURE_SIGNEXT = Feature.SIGNEXT;
+
+/** Enables a specific feature. */
+export function enableFeature(options: Options, feature: Feature): void {
+  options.features |= feature;
+}
+
 /** Finishes parsing. */
 export function finishParsing(parser: Parser): Program {
   return parser.finish();