Display hello world

src/document.rs

@@ -4,3 +4,19 @@ use crate::Row;
 pub struct Document {
     rows: Vec<Row>,
 }
+
+impl Document {
+    pub fn open() -> Self {
+        let mut rows = Vec::new();
+        rows.push(Row::from("Hello, World!"));
+        Self { rows }
+    }
+
+    pub fn row(&self, index: usize) -> Option<&Row> {
+        self.rows.get(index)
+    }
+
+    pub fn is_empty(&self) -> bool {
+        self.rows.is_empty()
+    }
+}

src/editor.rs

@@ -1,4 +1,5 @@
 use crate::Document;
+use crate::Row;
 use crate::Terminal;
 use termion::event::Key;
 
@@ -36,7 +37,7 @@ impl Editor {
         Self {
             should_quit: false,
             terminal: Terminal::default().expect("Failed to initialize terminal"),
-            document: Document::default(),
+            document: Document::open(),
             cursor_position: Position::default(),
         }
     }
@@ -112,13 +113,22 @@ impl Editor {
         println!("{}\r", welcome_message);
     }
 
+    pub fn draw_row(&self, row: &Row) {
+        let start = 0;
+        let end = self.terminal.size().width as usize;
+        let row = row.render(start, end);
+        println!("{}\r", row);
+    }
+
     fn draw_rows(&self) {
         let height = self.terminal.size().height;
 
-        for row in 0..height - 1 {
+        for terminal_row in 0..height - 1 {
             Terminal::clear_current_line();
 
-            if row == height / 3 {
+            if let Some(row) = self.document.row(terminal_row as usize) {
+                self.draw_row(row);
+            } else if self.document.is_empty() && terminal_row == height / 3 {
                 self.draw_welcome_message();
             } else {
                 println!("~\r");

src/row.rs

@@ -1,3 +1,21 @@
+use std::cmp;
+
 pub struct Row {
     string: String,
 }
+
+impl From<&str> for Row {
+    fn from(slice: &str) -> Self {
+        Self {
+            string: String::from(slice),
+        }
+    }
+}
+
+impl Row {
+    pub fn render(&self, start: usize, end: usize) -> String {
+        let end = cmp::min(end, self.string.len());
+        let start = cmp::min(start, end);
+        self.string.get(start..end).unwrap_or_default().to_string()
+    }
+}