From c331397619141d26f41626170c5db1658a2c6abd Mon Sep 17 00:00:00 2001
From: minjaesong <alswo9628@gmail.com>
Date: Thu, 22 Apr 2021 17:47:27 +0900
Subject: [PATCH] edit.js: tab key impl

---
 assets/JS_INIT.js              |  1 +
 assets/disk0/tvdos/bin/edit.js | 17 ++++++++++++++++-
 2 files changed, 17 insertions(+), 1 deletion(-)

diff --git a/assets/JS_INIT.js b/assets/JS_INIT.js
index f7e9ab1..d08bde3 100644
--- a/assets/JS_INIT.js
+++ b/assets/JS_INIT.js
@@ -387,6 +387,7 @@ con.KEY_PAGE_DOWN = 209;
 con.KEY_INSERT = 210;
 con.KEY_DELETE = 211;
 con.KEY_BACKSPACE = 8;
+con.KEY_TAB = 9;
 con.KEY_RETURN = 13;
 con.getch = function() {
     return sys.readKey();
diff --git a/assets/disk0/tvdos/bin/edit.js b/assets/disk0/tvdos/bin/edit.js
index 7e2f9dc..1f4342e 100644
--- a/assets/disk0/tvdos/bin/edit.js
+++ b/assets/disk0/tvdos/bin/edit.js
@@ -14,6 +14,7 @@ const COL_CARET_ROW = 81;
 const PAINT_START_X = 5;
 const PAINT_START_Y = 2;
 const BIG_STRIDE = 10000;
+const TAB_SIZE = 4;
 
 let filename = undefined;
 
@@ -171,7 +172,8 @@ function drawTextLineAbsolute(rowNumber, paintOffsetX) {
     con.color_pair(COL_TEXT, (rowNumber == cursorRow) ? COL_CARET_ROW : COL_BACK);
 
     for (let x = 0; x < paintWidth; x++) {
-        let text = textbuffer[rowNumber] + String.fromCharCode(254);
+        let text = textbuffer[rowNumber];
+        if (rowNumber < textbuffer.length - 1) text += String.fromCharCode(254);
         let charCode =
             // nonexisting text row
             (undefined === textbuffer[rowNumber]) ? 0 :
@@ -472,6 +474,19 @@ while (!exit) {
         cursoringCol = textbuffer[cursorRow].length;
         cursorMoveRelative(BIG_STRIDE, 0);
     }
+    else if (key == con.KEY_TAB) { // insert spaces appropriately
+        let tabsize = TAB_SIZE - (cursorCol % TAB_SIZE);
+
+        for (let k = 0; k < tabsize; k++) {
+            insertChar(32, cursorRow, cursorCol);
+            // identical to con.KEY_RIGHT
+            cursoringCol = cursorCol + 1;
+            if (cursoringCol > textbuffer[cursorRow].length) cursoringCol = textbuffer[cursorRow].length;
+            cursorMoveRelative(1,0);
+            // end of con.KEY_RIGHT
+        }
+        drawTextLineAbsolute(cursorRow, scrollHor); drawLnCol(); gotoText();
+    }
     else if (key >= 32 && key < 128) { // printables (excludes \n)
         insertChar(key, cursorRow, cursorCol);
         // identical to con.KEY_RIGHT