Add & register more basic commands

src/vm/commands/contains.ts

@@ -0,0 +1,18 @@
+import { LexInput } from "../lexer.js";
+import {Command, ParseContext, StrTerm} from "./command.js";
+
+export class Contains extends Command<{ find: StrTerm }> {
+    attemptParse(context: ParseContext): { find: StrTerm } {
+        return {
+            find: context.popTerm(),
+        }
+    }
+
+    getDisplayName(): string {
+        return 'contains'
+    }
+
+    isParseCandidate(token: LexInput): boolean {
+        return this.isKeyword(token, 'contains')
+    }
+}