moving everything neatly into the assets directory

assets/disk0/tvdos/bin/less.js

@@ -0,0 +1,143 @@
+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 pan = -1;
+let termW = con.getmaxyx()[1];
+let termH = con.getmaxyx()[0] - 1;
+let buf = "";
+let fileContent = filesystem.readAll(_G.shell.getCurrentDrive());
+let key = -1;
+let panSize = termW >> 1;
+let scrollSize = termH >> 3;
+
+// initialise some helper variables
+let lineToBytes = [0];
+let maxPan = 0;
+let maxPanCur = 0;
+for (let i = 0; i < fileContent.length; i++) {
+    let char = fileContent.charCodeAt(i);
+    maxPanCur += 1;
+    if (char == 10 || char == 13) {
+        lineToBytes.push(i + 1);
+        if (maxPanCur > maxPan) maxPan = maxPanCur;
+        maxPanCur = 0;
+    }
+}
+
+let startAddr = -1;
+let paintCur = 0;
+let cy = 1;
+let cx = 1;
+let char = -1;
+
+let numbuf = 0;
+
+let resetKeyReadStatus = function() {
+    numbuf = 0;
+}
+
+let repaint = function() {
+    con.move(1,1); con.clear();
+
+    startAddr = lineToBytes[scroll];
+    cy = 1; cx = -pan; paintCur = 0;
+    while (cy <= termH) {
+        char = fileContent.charCodeAt(startAddr + paintCur);
+        if (isNaN(char)) break;
+        if (cy <= termH) {
+            if (cx >= 0 && cx < termW) {
+                con.move(cy, cx);
+                if (char != 10 && char != 13)
+                    con.addch(char);
+            }
+            cx += 1;
+        }
+        if (char == 10 || char == 13) {
+            cy += 1;
+            cx = -pan;
+        }
+        paintCur += 1;
+    }
+}
+
+repaint();
+con.move(termH + 1, 1);
+print(":"+" ".repeat(termW - 2));
+con.move(termH + 1, 2);
+while (true) {
+    // read a key
+    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 -= scrollSize;
+        if (scroll < 0) scroll = 0;
+        repaint();
+    }
+    /*down*/else if (key == 20) {
+        scroll += scrollSize;
+        if (scroll > lineToBytes.length - termH) scroll = lineToBytes.length - termH;
+        repaint();
+    }
+    /*left*/else if (key == 21 && pan > 0) {
+        pan -= panSize;
+        repaint();
+    }
+    /*right*/else if (key == 22 && pan < maxPan - termW) {
+        pan += panSize;
+        repaint();
+    }
+    /*0-9*/else if (key >= 48 && key <= 57) {
+        print(String.fromCharCode(key));
+        numbuf = (numbuf * 10) + (key - 48);
+    }
+    /*bksp*/else if (key == 8) {
+        if (numbuf > 0) print(String.fromCharCode(key));
+        numbuf = (numbuf / 10)|0;
+    }
+    /*u*/else if (key == 117) {
+        scroll -= numbuf;
+        if (scroll < 0) scroll = 0;
+        repaint();
+    }
+    /*d*/else if (key == 100) {
+        scroll += numbuf;
+        if (scroll > lineToBytes.length - termH) scroll = lineToBytes.length - termH;
+        repaint();
+    }
+
+
+    if (!(key >= 48 && key <= 57 || key == 8)) {
+        resetKeyReadStatus();
+        con.move(termH + 1, 1);
+        print(":"+" ".repeat(termW - 2));
+        con.move(termH + 1, 2);
+    }
+
+    serial.println("numbuf = "+numbuf);
+}
+
+con.move(termH + 1, 1);
+return 0;