basic interpreter wip

assets/tbas/basic.js

@@ -0,0 +1,56 @@
+var vmemsize = 60300;
+var vmemused = 0;
+var cmdbuf = []; // index: line number
+var prompt = "Ok";
+
+var linenumRe = /^[0-9]+ +[^0-9]/;
+
+println("Terran BASIC 1.0  "+vmemsize+" bytes free");
+println(prompt);
+
+var basicFunctions = new Object();
+basicFunctions._basicList = function(v, i, arr) {
+    if (i < 100) print(" ");
+    print(i);
+    print(" ");
+    println(v);
+};
+basicFunctions.list = function(args) {
+    if (args.length == 1) {
+        cmdbuf.forEach(basicFunctions._basicList);
+    }
+    else if (args.length == 2) {
+        if (typeof cmdbuf[args[1]] != "undefined")
+            basicFunctions._basicList(cmdbuf[args[1]], args[1], undefined);
+    }
+    else {
+        var lastIndex = (args[2] === ".") ? cmdbuf.length - 1 : (args[2] | 0);
+        var i = 0;
+        for (i = args[1]; i <= lastIndex; i++) {
+            var cmd = cmdbuf[i];
+            if (typeof cmd != "undefined") {
+                basicFunctions._basicList(cmd, i, cmdbuf);
+            }
+        }
+    }
+};
+
+while (true) {
+    var line = vm.read();
+    line = line.trim();
+
+    if (linenumRe.test(line)) {
+        var i = line.indexOf(" ");
+        cmdbuf[line.slice(0, i)] = line.slice(i + 1, line.length);
+    }
+    else if (line.length > 0) {
+        try {
+            var cmd = line.split(" ");
+            basicFunctions[cmd[0]](cmd);
+        }
+        catch (e) {
+            println("Syntax error");
+        }
+        println(prompt);
+    }
+}