Replace StringRange w/ an actual StrRVal + more command implementations

src/vm/output.ts

@@ -0,0 +1,13 @@
+import {StrRVal} from "./commands/command.js";
+
+export const getSubjectDisplay = (sub: StrRVal): string => {
+    if ( sub.term === 'string' ) {
+        return sub.value
+    }
+
+    if ( sub.term === 'int' ) {
+        return String(sub.term)
+    }
+
+    return JSON.stringify(sub.value, null, '\t')  // fixme
+}