First output of welcome message

src/bun/terminal_io.ts

@@ -14,8 +14,8 @@ function getSizeFromTput(): ITerminalSize {
 	);
 
 	return {
-		rows: (rows > 0) ? rows : 25,
-		cols: (cols > 0) ? cols : 80,
+		rows: (rows > 0) ? rows + 1 : 25,
+		cols: (cols > 0) ? cols + 1 : 80,
 	};
 }
 

src/common/editor/ansi.ts

@@ -3,8 +3,11 @@ function esc(pieces: TemplateStringsArray): string {
 }
 
 export const Ansi = {
+	ClearLine: esc`K`,
 	ClearScreen: esc`2J`,
 	ResetCursor: esc`H`,
+	HideCursor: esc`?25l`,
+	ShowCursor: esc`?25h`,
 	moveCursor: function moveCursor(row: number, col: number): string {
 		return `\x1b${row};${col}H`;
 	},

src/common/editor/buffer.ts

@@ -1,3 +1,5 @@
+import { strlen } from '../strings.ts';
+
 class Buffer {
 	#b = '';
 
@@ -19,6 +21,10 @@ class Buffer {
 	getBuffer(): string {
 		return this.#b;
 	}
+
+	strlen(): number {
+		return strlen(this.#b);
+	}
 }
 
 export default Buffer;

src/common/editor/editor.ts

@@ -1,8 +1,13 @@
 import Ansi from './ansi.ts';
 import Buffer from './buffer.ts';
-import { importDefaultForRuntime } from '../runtime.ts';
-import { ctrl_key } from '../strings.ts';
-import { ITerminalSize } from '../types.ts';
+import {
+	ctrl_key,
+	importDefaultForRuntime,
+	ITerminalSize,
+	strlen,
+	truncate,
+	VERSION,
+} from '../mod.ts';
 
 export class Editor {
 	#buffer: Buffer;
@@ -29,27 +34,46 @@ export class Editor {
 		}
 	}
 
+	// -------------------------------------------------------------------------------------------------------------------
+	// Terminal Output / Drawing
+	// -------------------------------------------------------------------------------------------------------------------
+
 	/**
 	 * Clear the screen and write out the buffer
 	 */
 	public async refreshScreen(): Promise<void> {
 		const { write } = await importDefaultForRuntime('terminal_io');
 
-		this.clearScreen();
+		this.#buffer.append(Ansi.HideCursor);
+		this.#buffer.append(Ansi.ResetCursor);
 		this.drawRows();
+		this.#buffer.append(Ansi.ShowCursor);
 
 		await write(this.#buffer.getBuffer());
 		this.#buffer.clear();
 	}
 
-	private drawRows(): void {
-		for (let y = 0; y <= this.#screenRows; y++) {
-			this.#buffer.appendLine('~');
-		}
+	private clearScreen(): void {
+		importDefaultForRuntime('terminal_io').then(({ write }) => {
+			this.#buffer.append(Ansi.ClearScreen);
+			this.#buffer.append(Ansi.ResetCursor);
+			write(this.#buffer.getBuffer()).then(() => {});
+		});
 	}
 
-	private clearScreen(): void {
-		this.#buffer.append(Ansi.ClearScreen);
-		this.#buffer.append(Ansi.ResetCursor);
+	private drawRows(): void {
+		for (let y = 0; y < this.#screenRows; y++) {
+			if (y === this.#screenRows / 3) {
+				const message = `Kilo editor -- version ${VERSION}`;
+				this.#buffer.append(truncate(message, this.#screenCols));
+			} else {
+				this.#buffer.append('~');
+			}
+
+			this.#buffer.append(Ansi.ClearLine);
+			if (y < this.#screenRows - 1) {
+				this.#buffer.append('\r\n');
+			}
+		}
 	}
 }

src/common/mod.ts

@@ -3,3 +3,5 @@ export * from './runtime.ts';
 export * from './strings.ts';
 export * from './termios.ts';
 export type * from './types.ts';
+
+export const VERSION = '0.0.1';

src/common/strings.ts

@@ -6,19 +6,23 @@ export function chars(s: string): string[] {
 	return s.split(/(?:)/u);
 }
 
+/**
+ * Get the 'character length' of a string, not its UTF16 byte count
+ * @param s - the string to check
+ */
+export function strlen(s: string): number {
+	return chars(s).length;
+}
+
 /**
  * Is the character part of ascii?
  *
  * @param char - a one character string to check
  */
 export function is_ascii(char: string): boolean {
-	if (typeof char !== 'string') {
-		return false;
-	}
-
 	return chars(char).every((char) => {
 		const point = char.codePointAt(0);
-		if (typeof point === 'undefined') {
+		if (point === undefined) {
 			return false;
 		}
 
@@ -58,3 +62,17 @@ export function ctrl_key(char: string): string {
 	// If it's not ascii, just return the input key code
 	return char;
 }
+
+/**
+ * Trim a string to a max number of characters
+ * @param s
+ * @param maxLen
+ */
+export function truncate(s: string, maxLen: number): string {
+	const chin = chars(s);
+	if (maxLen >= chin.length) {
+		return s;
+	}
+
+	return chin.slice(0, maxLen).join('');
+}

src/common/strings_test.ts

@@ -1,5 +1,12 @@
 import { importDefaultForRuntime, ITestBase } from './mod.ts';
-import { chars, is_ascii } from './strings.ts';
+import {
+	chars,
+	ctrl_key,
+	is_ascii,
+	is_control,
+	strlen,
+	truncate,
+} from './strings.ts';
 
 const t: ITestBase = await importDefaultForRuntime('test_base');
 
@@ -7,7 +14,42 @@ t.test('chars fn properly splits strings into unicode characters', () => {
 	t.assertEquals(chars('😺😸😹'), ['😺', '😸', '😹']);
 });
 
+t.test('ctrl_key fn returns expected values', () => {
+	const ctrl_a = ctrl_key('a');
+	t.assertTrue(is_control(ctrl_a));
+	t.assertEquals(ctrl_a, String.fromCodePoint(0x01));
+
+	const invalid = ctrl_key('😺');
+	t.assertFalse(is_control(invalid));
+	t.assertEquals(invalid, '😺');
+});
+
 t.test('is_ascii properly discerns ascii chars', () => {
 	t.assertTrue(is_ascii('asjyverkjhsdf1928374'));
 	t.assertFalse(is_ascii('😺acalskjsdf'));
 });
+
+t.test('is_control fn works as expected', () => {
+	t.assertFalse(is_control('abc'));
+	t.assertTrue(is_control(String.fromCodePoint(0x01)));
+	t.assertFalse(is_control('😺'));
+});
+
+t.test('strlen fn returns expected length for multibyte characters', () => {
+	t.assertEquals(strlen('😺😸😹'), 3);
+	t.assertNotEquals('😺😸😹'.length, strlen('😺😸😹'));
+
+	// Skin tone modifier + base character
+	t.assertEquals(strlen('🤰🏼'), 2);
+	t.assertNotEquals('🤰🏼'.length, strlen('🤰🏼'));
+
+	// This has 4 sub-characters, and 3 zero-width-joiners
+	t.assertEquals(strlen('👨‍👩‍👧‍👦'), 7);
+	t.assertNotEquals('👨‍👩‍👧‍👦'.length, strlen('👨‍👩‍👧‍👦'));
+});
+
+t.test('truncate shortens strings', () => {
+	t.assertEquals(truncate('😺😸😹', 1), '😺');
+	t.assertEquals(truncate('😺😸😹', 5), '😺😸😹');
+	t.assertEquals(truncate('👨‍👩‍👧‍👦', 5), '👨‍👩‍👧');
+});

src/scroll.ts

@@ -20,12 +20,13 @@ export async function main() {
 	const t = await getTermios();
 	t.enableRawMode();
 	onExit(() => {
-		console.info('Exit handler called, disabling raw mode');
+		console.log('Exit handler called, disabling raw mode\r\n');
 		t.disableRawMode();
 	});
 
 	// Create the editor itself
 	const editor = new Editor(getSize());
+	await editor.refreshScreen();
 
 	// The main event loop
 	for await (const chunk of inputLoop()) {