rudimentary and perhaps broken LESS impl

assets/JS_INIT.js

@@ -395,6 +395,7 @@ con.color_pair = function(fore, back) { // 0..255
 con.clear = function() {
     print(String.fromCharCode(27,91)+"2J");
 };
+// @params arg 0 to hide, nonzero to show
 con.curs_set = function(arg) {
     print(String.fromCharCode(27,91)+"?25"+(((arg|0) == 0) ? "l" : "h"));
 };

assets/keytest.js

@@ -0,0 +1,6 @@
+println("Hit Ctrl-C or Ctrl-D to exit");
+while (true) {
+    let key = con.getch()
+    println(key);
+    if (key == 3 || key == 4) break;
+}

assets/tvdos/bin/command.js

@@ -410,6 +410,7 @@ if (goInteractive) {
                         cmdHistory.push(cmdbuf);
 
                     cmdHistoryScroll = 0;
+                    con.curs_set(1);
 
                     break;
                 }

assets/tvdos/bin/less.js

@@ -0,0 +1,90 @@
+if (exec_args[1] === undefined) {
+    println('Missing filename ("less -?" for help)');
+    return 0;
+}
+
+/*let help = "\n
+SUMMARY OF COMMANDS\n
+\n
+  h   H            Display this help\n
+  q   Q            Exit
+\n"*/
+
+if (exec_args[1].startsWith("-?")) {
+    println("less <filename>");
+    return 0;
+}
+
+let fileOpened = filesystem.open(_G.shell.getCurrentDrive(), _G.shell.resolvePathInput(exec_args[1]).string, "R");
+if (!fileOpened) {
+    printerrln(_G.shell.resolvePathInput(exec_args[1]).string+": cannot open");
+    return 1;
+}
+
+let scroll = 0;
+let termW = con.getmaxyx()[1];
+let termH = con.getmaxyx()[0] - 1;
+let bufsize = termW * termH;
+let buf = "";
+let fileContent = filesystem.readAll(_G.shell.getCurrentDrive());
+let key = -1;
+
+// initialise some helper variables
+let lineToBytes = [0];
+for (let i = 0; i < fileContent.length; i++) {
+    let char = fileContent.charCodeAt(i);
+    if (char == 10 || char == 13) {
+        lineToBytes.push(i + 1);
+    }
+}
+
+serial.println(lineToBytes);
+
+let startAddr = -1;
+let paintCur = 0;
+let cy = 1;
+let cx = 1;
+let char = -1;
+
+let repaint = function() {
+    con.move(1,1); con.clear();
+
+    startAddr = lineToBytes[scroll];
+    cy = 1; cx = 1; paintCur = 0;
+    while (cy <= termH && cx <= termW) {
+        char = fileContent.charCodeAt(startAddr + paintCur);
+        if (cy <= termH) {
+            con.move(cy, cx);
+            if (char != 10 && char != 13)
+                con.addch(char);
+            cx += 1;
+        }
+        if (char == 10 || char == 13) {
+            cy += 1;
+            cx = 1;
+        }
+        paintCur += 1;
+    }
+}
+
+repaint();
+while (true) {
+    // read a key
+    con.mvaddch(termH + 1,1,58);
+    con.move(termH + 1, 2);
+    key = con.getch();
+    // do something with key read
+    /*Q*/if (key == 113 || key == 81) break;
+    /*R*/else if (key == 114 || key == 82) repaint();
+    /*up*/else if (key == 19 && scroll > 0) {
+        scroll -= 1;
+        repaint();
+    }
+    /*down*/else if (key == 20 && scroll < lineToBytes.length - 1) {
+        scroll += 1;
+        repaint();
+    }
+}
+
+con.move(termH + 1, 1);
+return 0;

src/net/torvald/tsvm/VMJSR223Delegate.kt

@@ -41,6 +41,11 @@ class VMJSR223Delegate(val vm: VM) {
     }
     fun println() = print('\n')
 
+    /**
+     * @return key being hit, of which:
+     * a-zA-Z1-9: corresponding ASCII code
+     * ^A-^Z: 1 through 26
+     */
     fun readKey(): Int {
         val inputStream = vm.getInputStream()
         var key: Int = inputStream.read()