basic visual buffer support

core/buffer.py

@@ -1,9 +1,9 @@
 import curses
 
 
-def write_buffer(stdscr, data):
+def write_buffer(screen, data):
-    count = 0
+    for index, line in enumerate(data["buffer_list"][data["visible_y"]:]):
-    for line in data["buffer_list"]:
+        if index < data["height"] - 2:
             str_line = "".join(line)
-        stdscr.addstr(count, len(data["info_bar"][0]), str_line + (" " * (len(line) - 1)), curses.color_pair(1))
+            # [data["visible_x"]:1:data["width"] - data["visible_x"]]
-        count += 1
+            screen.addstr(index, len(data["info_bar"][0]), str_line + (" " * (len(line) - 1)), curses.color_pair(1))

core/cursor.py

@@ -1,3 +1,6 @@
+from core import utils, buffer
+
+
 def cursor_mode(mode):
     if mode == "block":
         print("\033[2 q")
@@ -13,9 +16,15 @@ def cursor_mode(mode):
 
 
 def check_cursor(data):
-    if data["cursor_y"] == len(data["buffer_list"]):
+    if data["cursor_y"] + data["visible_y"] == len(data["buffer_list"]):
         data["cursor_y"] -= 1
 
+    if data["cursor_y"] == data["height"] - 2 and not data["cursor_y"] + data["visible_y"] == len(data["buffer_list"]):
+        data["visible_y"] += 1
+
+    elif data["cursor_y"] == 0 and data["buffer_list"][data["visible_y"]] != data["buffer_list"][0]:
+        data["visible_y"] -= 1
+
     elif data["cursor_x"] > len(data["buffer_list"][data["cursor_y"]]):
         data["cursor_x"] = len(data["buffer_list"][data["cursor_y"]])
 
@@ -27,9 +36,9 @@ def check_cursor(data):
     return data
 
 
-def move(stdscr, data):
+def move(screen, data):
     # Calculate a valid cursor position from data
     data = check_cursor(data)
 
     # Move the cursor
-    stdscr.move(data["cursor_y"], data["cursor_x"])
+    screen.move(data["cursor_y"], data["cursor_x"])

core/files.py

@@ -1,4 +1,4 @@
-def open_file(file):
+def open_file(file_name):
-    with open(file) as f:
+    with open(file_name) as f:
         lines = f.readlines()
     return lines

core/mode.py

@@ -1,17 +1,17 @@
 from modes import normal, insert, command
 
 
-def activate(stdscr, data):
+def activate(screen, data):
     if data["mode"] == "normal":
         data["mode_color"] = 6
-        data = normal.activate(stdscr, data)
+        data = normal.activate(screen, data)
 
     elif data["mode"] == "insert":
         data["mode_color"] = 12
-        data = insert.activate(stdscr, data)
+        data = insert.activate(screen, data)
 
     elif data["mode"] == "command":
         data["mode_color"] = 6
-        data = command.activate(stdscr, data)
+        data = command.activate(screen, data)
 
     return data

core/statusbar.py

@@ -23,21 +23,23 @@ def themes(data):
     return colors, icon, mode, file
 
 
-def refresh(stdscr, data):
+def refresh(screen, data):
+    # Calculate the theme
     colors, icon, mode, file = themes(data)
+
     # Render icon
-    stdscr.addstr(data["height"] - 2, 0, icon,
+    screen.addstr(data["height"] - 2, 0, icon,
                   curses.color_pair(colors[0]) | curses.A_BOLD)
 
     # Render mode
-    stdscr.addstr(data["height"] - 2, len(icon), mode,
+    screen.addstr(data["height"] - 2, len(icon), mode,
                   curses.color_pair(colors[1]) | curses.A_BOLD)
 
     # Render file name
-    stdscr.addstr(data["height"] - 2, len(icon) + len(mode), file,
+    screen.addstr(data["height"] - 2, len(icon) + len(mode), file,
                   curses.color_pair(colors[2]) | curses.A_BOLD)
 
     # Rest of the bar
-    stdscr.addstr(data["height"] - 2, len(icon) + len(mode) + len(file),
+    screen.addstr(data["height"] - 2, len(icon) + len(mode) + len(file),
                   " " * (data["width"] - (len(icon) + len(mode) + len(file))),
                   curses.color_pair(colors[3]))

core/utils.py

@@ -2,36 +2,50 @@ from sys import exit
 import curses
 
 
-def goodbye(stdscr, data):
+def refresh_window_size(screen, data):
-    # The prompt message
+    # Get the height and width of the screen
-    saved = "All changes are saved."
+    data["height"], data["width"] = screen.getmaxyx()
-    prompt = "Really quit? (y or n): "
 
-    # Clear the bottom line
+    # Return the data as changes may have been made
-    stdscr.addstr(data["height"] - 1, 0, " " * (data["width"] - 1), curses.color_pair(1))
+    return data
 
+
+def clear_line(screen, data, line):
+    # Clear the specified line
+    screen.addstr(line, 0, " " * (data["width"] - 1), curses.color_pair(1))
+
+
+def prompt(screen, data, text):
     # Print the prompt
-    stdscr.addstr(data["height"] - 1, 0, prompt, curses.color_pair(11))
+    screen.addstr(data["height"] - 1, 0, text, curses.color_pair(11))
 
     # Wait for and capture a key press from the user
-    key = stdscr.getch()
+    return screen.getch()
+
+
+def goodbye(screen, data):
+    # Create a goodbye prompt
+    key = prompt(screen, data, "Really quit? (y or n): ")
+
+    # Clear the bottom line
+    clear_line(screen, data, data["height"] - 1)
 
     if key == ord("y"):
         # Only exit if the key was "y", a confirmation
         exit()
 
     # Clear the bottom line again
-    stdscr.addstr(data["height"] - 1, 0, " " * (data["width"] - 1), curses.color_pair(1))
+    clear_line(screen, data, data["height"] - 1)
 
 
-def error(stdscr, data, error_msg):
+def error(screen, data, error_msg):
     # Print the error message to the bottom line
     error_msg = f"ERROR: {error_msg}"
-    stdscr.addstr(data["height"] - 1, 0, error_msg, curses.color_pair(3))
+    screen.addstr(data["height"] - 1, 0, error_msg, curses.color_pair(3))
-    stdscr.addstr(data["height"] - 1, len(error_msg) + 1, "(press any key) ", curses.color_pair(1))
+    screen.addstr(data["height"] - 1, len(error_msg) + 1, "(press any key) ", curses.color_pair(1))
 
     # Wait for a key to be pressed
-    stdscr.getch()
+    screen.getch()
 
     # Clear the bottom line
-    stdscr.addstr(data["height"] - 1, 0, " " * (data["width"] - 1), curses.color_pair(1))
+    clear_line(screen, data, data["height"] - 1)

core/welcome.py

@@ -1,9 +1,9 @@
 import curses
 
 
-def start_screen(stdscr):
+def start_screen(screen):
     # Get window height and width
-    height, width = stdscr.getmaxyx()
+    height, width = screen.getmaxyx()
 
     # Startup text
     title = "λ Lambda"
@@ -20,10 +20,10 @@ def start_screen(stdscr):
     start_y = int((height // 2) - 2)
 
     # Rendering title
-    stdscr.addstr(start_y, start_x_title, title, curses.color_pair(7) | curses.A_BOLD)
+    screen.addstr(start_y, start_x_title, title, curses.color_pair(7) | curses.A_BOLD)
 
     # Print the subtext
     for text in subtext:
         start_y += 1
         start_x = int((width // 2) - (len(text) // 2) - len(text) % 2)
-        stdscr.addstr(start_y, start_x, text)
+        screen.addstr(start_y, start_x, text)

lambda

@@ -1,3 +1,3 @@
 #!/bin/sh
 
-python3 ./lambda.py $@
+python3 ./lambda.py "$@"

lambda.py

@@ -4,7 +4,7 @@ import curses
 import argparse
 
 
-def start(stdscr, buffer_name, buffer_list):
+def start(screen, buffer_name, buffer_list):
     # Initialise data before starting
     data = {
         "cursor_y": 0,
@@ -16,6 +16,8 @@ def start(stdscr, buffer_name, buffer_list):
         "info_bar": ["  "],
         "buffer_name": buffer_name,
         "buffer_list": buffer_list,
+        "visible_y": 0,
+        "visible_x": 0,
         "statusbar_theme": "filled"
     }
 
@@ -27,22 +29,28 @@ def start(stdscr, buffer_name, buffer_list):
 
     # Start the screen
     if data["buffer_name"] == "[No Name]":
-        welcome.start_screen(stdscr)
+        welcome.start_screen(screen)
 
     # Main loop
     while True:
         # Get the height and width of the screen
-        data["height"], data["width"] = stdscr.getmaxyx()
+        data["height"], data["width"] = screen.getmaxyx()
 
         # Write the buffer to the screen
-        buffer.write_buffer(stdscr, data)
+        buffer.write_buffer(screen, data)
 
         # Activate the next mode
-        data = mode.activate(stdscr, data)
+        data = mode.activate(screen, data)
+
+        # Write the buffer to the screen
+        buffer.write_buffer(screen, data)
 
         # Refresh and clear the screen
-        stdscr.refresh()
+        screen.refresh()
-        stdscr.clear()
+        screen.clear()
+
+        # Write the buffer to the screen
+        buffer.write_buffer(screen, data)
 
 
 def main():

modes/command.py

@@ -2,10 +2,10 @@ from core import statusbar, utils
 import curses
 
 
-def execute(stdscr, data, commands):
+def execute(screen, data, commands):
     if not commands:
         # Quit if there are no commands, don't check anything
-        return
+        return data
 
     for command in commands:
         if command == "w":
@@ -14,9 +14,10 @@ def execute(stdscr, data, commands):
 
         elif command == "q":
             # Goodbye prompt
-            utils.goodbye(stdscr, data)
+            utils.goodbye(screen, data)
 
         elif command == "t":
+            # Theme switcher
             if data["statusbar_theme"] == "filled":
                 data["statusbar_theme"] = "bare"
 
@@ -24,29 +25,29 @@ def execute(stdscr, data, commands):
                 data["statusbar_theme"] = "filled"
 
         else:
-            utils.error(stdscr, data, f"Not an editor command: '{command}'")
+            utils.error(screen, data, f"Not an editor command: '{command}'")
 
     return data
 
 
-def activate(stdscr, data):
+def activate(screen, data):
     # Initialise variables
     commands = []
 
     # Visibly switch to command mode
-    statusbar.refresh(stdscr, data)
+    statusbar.refresh(screen, data)
-    stdscr.addstr(data["height"]-1, 0, ":")
+    screen.addstr(data["height"]-1, 0, ":")
-    stdscr.move(data["height"]-1, 1)
+    screen.move(data["height"]-1, 1)
 
     # Main loop
     while True:
         # Get a key inputted by the user
-        key = stdscr.getch()
+        key = screen.getch()
 
         # Handle subtracting a key (backspace)
         if key == curses.KEY_BACKSPACE:
             # Write whitespace over characters to refresh it
-            stdscr.addstr(data["height"]-1, 1, " " * len(commands))
+            screen.addstr(data["height"]-1, 1, " " * len(commands))
 
             if commands:
                 # Subtract a character
@@ -63,10 +64,10 @@ def activate(stdscr, data):
 
         elif key in (curses.KEY_ENTER, ord('\n'), ord('\r'), ord(":"), ord(";")):
             # Execute commands
-            data = execute(stdscr, data, commands)
+            data = execute(screen, data, commands)
 
             # Clear the bottom bar
-            stdscr.addstr(data["height"] - 1, 0, " " * (data["width"] - 1))
+            screen.addstr(data["height"] - 1, 0, " " * (data["width"] - 1))
 
             # Return to normal mode after executing a command
             data["mode"] = "normal"
@@ -83,7 +84,7 @@ def activate(stdscr, data):
         friendly_command = "".join(commands)
 
         # Write the commands to the screen
-        stdscr.addstr(data["height"]-1, 1, friendly_command)
+        screen.addstr(data["height"]-1, 1, friendly_command)
 
         # Move the cursor the end of the commands
-        stdscr.move(data["height"]-1, len(commands)+1)
+        screen.move(data["height"]-1, len(commands)+1)

modes/insert.py

@@ -5,22 +5,22 @@ def execute(data, key):
     return data
 
 
-def activate(stdscr, data):
+def activate(screen, data):
     # Refresh the status bar with a different colour for insert
     data["statusbar_colors"] = [8, 12, 14, 2]
-    statusbar.refresh(stdscr, data)
+    statusbar.refresh(screen, data)
 
     # Refresh the status bar
-    statusbar.refresh(stdscr, data)
+    statusbar.refresh(screen, data)
 
     # Move the cursor
-    cursor.move(stdscr, data)
+    cursor.move(screen, data)
 
     # Switch to a line cursor
     cursor.cursor_mode("line")
 
     # Wait for and capture a key press from the user
-    key = stdscr.getch()
+    key = screen.getch()
 
     # Exit insert mode
     if key == 27:

modes/normal.py

@@ -1,4 +1,5 @@
 from core import statusbar, cursor
+import curses
 
 
 def execute(data, key):
@@ -34,18 +35,18 @@ def execute(data, key):
     return data
 
 
-def activate(stdscr, data):
+def activate(screen, data):
     # Refresh the status bar
-    statusbar.refresh(stdscr, data)
+    statusbar.refresh(screen, data)
 
     # Move the cursor
-    cursor.move(stdscr, data)
+    cursor.move(screen, data)
 
     # Switch the cursor to a block
     cursor.cursor_mode("block")
 
     # Wait for and capture a key press from the user
-    key = stdscr.getch()
+    key = screen.getch()
 
     # Check against the keybindings
     data = execute(data, key)