lambda-rewrite

core/buffers.py

@@ -0,0 +1,46 @@
+import os
+
+
+class Buffer:
+    def __init__(self, path: str, name: str = None, data: list = None):
+        self.path = path
+        self.name = name or "[No Name]"
+        self.data = data or [[""]]
+
+    @staticmethod
+    def remove_char(string: str, index: int) -> str:
+        # Remove a character from a string at a given index
+        return string[:index] + string[index + 1:]
+
+    @staticmethod
+    def insert_char(string: str, index: int, char: (str, chr)) -> str:
+        # Insert a character into a string at a given index
+        return string[:index] + char + string[index:]
+
+
+def open_file(file_name):
+    # Open the file
+    with open(file_name) as f:
+        # Convert it into a list of lines
+        lines = f.readlines()
+
+    # Return the list of lines
+    return lines
+
+
+def load_file(file_path=None):
+    # Default settings for a file
+    file_name = "[No Name]"
+    file_data = [[""]]
+
+    if file_path:
+        # Set the file's name
+        file_name = os.path.basename(file_path)
+
+        # Only if the file actually exists
+        if os.path.exists(file_path):
+            # Open the file as a list of lines
+            file_data = open_file(file_name)
+
+    # Return a dictionary which will become all the data about the buffer
+    return Buffer(file_path, file_name, file_data)

core/colors.py

@@ -1,20 +1,51 @@
 import curses
 
 
+class Codes:
+    # Color codes
+    red = '\033[91m'
+    green = '\033[92m'
+    blue = '\033[94m'
+    yellow = '\033[93m'
+    cyan = '\033[96m'
+    magenta = '\033[95m'
+    white = '\033[97m'
+    selected_white = '\033[47m'
+    selected_green = '\033[42m'
+    strike = '\033[9m'
+    italic = '\033[3m'
+    end = '\033[0m'
+
+
 def init_colors():
-    # Start colors in curses
+    # Activate color support
     curses.start_color()
+
+    # Foreground: WHITE, Background: BLACK
     curses.init_pair(1, curses.COLOR_WHITE,    curses.COLOR_BLACK)
+    # Foreground: BLACK, Background: WHITE
     curses.init_pair(2, curses.COLOR_BLACK,    curses.COLOR_WHITE)
+    # Foreground: RED, Background: BLACK
     curses.init_pair(3, curses.COLOR_RED,      curses.COLOR_BLACK)
+    # Foreground: BLACK, Background: RED
     curses.init_pair(4, curses.COLOR_BLACK,    curses.COLOR_RED)
+    # Foreground: GREEN, Background: BLACK
     curses.init_pair(5, curses.COLOR_GREEN,    curses.COLOR_BLACK)
+    # Foreground: BLACK, Background: GREEN
     curses.init_pair(6, curses.COLOR_BLACK,    curses.COLOR_GREEN)
+    # Foreground: YELLOW, Background: BLACK
     curses.init_pair(7, curses.COLOR_YELLOW,   curses.COLOR_BLACK)
+    # Foreground: BLACK, Background: YELLOW
     curses.init_pair(8, curses.COLOR_BLACK,    curses.COLOR_YELLOW)
+    # Foreground: CYAN, Background: BLACK
     curses.init_pair(9, curses.COLOR_CYAN,     curses.COLOR_BLACK)
+    # Foreground: BLACK, Background: CYAN
     curses.init_pair(10, curses.COLOR_BLACK,   curses.COLOR_CYAN)
+    # Foreground: BLUE, Background: BLACK
     curses.init_pair(11, curses.COLOR_BLUE,    curses.COLOR_BLACK)
+    # Foreground: BLACK, Background: BLUE
     curses.init_pair(12, curses.COLOR_BLACK,   curses.COLOR_BLUE)
+    # Foreground: MAGENTA, Background: BLACK
     curses.init_pair(13, curses.COLOR_MAGENTA, curses.COLOR_BLACK)
+    # Foreground: BLACK, Background: MAGENTA
     curses.init_pair(14, curses.COLOR_BLACK,   curses.COLOR_MAGENTA)

core/components.py

@@ -0,0 +1,31 @@
+from core import utils
+import curses
+
+
+class StatusBar:
+    def __init__(self, instance):
+        self.instance = instance
+        self.mode = instance.mode.upper()
+        self.file = instance.buffer.name or "[No Name]"
+        self.icon = instance.config["icon"] or "λ"
+        self.colors = (7, 5, 13)
+        self.components = [self.icon, self.mode, self.file]
+
+    def render(self):
+        x = 1
+        utils.clear(self.instance, self.instance.height - 2, 0)
+        for count, component in enumerate(self.components):
+            self.instance.screen.addstr(self.instance.height - 2, x, component,
+                                        curses.color_pair(self.colors[count]) | curses.A_BOLD)
+            x += len(component) + 1
+
+
+class Components:
+    def __init__(self, components: dict = None):
+        self.components = components or {
+            "bottom": [StatusBar],
+        }
+
+    def render(self, instance):
+        for component in self.components["bottom"]:
+            component(instance).render()

core/cursors.py

@@ -0,0 +1,40 @@
+import curses
+
+
+def cursor_mode(mode):
+    if mode == "block":
+        print("\033[2 q")
+
+    elif mode == "line":
+        print("\033[6 q")
+
+    elif mode == "hidden":
+        curses.curs_set(0)
+
+    elif mode == "visible":
+        curses.curs_set(1)
+
+
+def cursor_push(cursor: list, direction: (int, str)) -> list:
+    if direction in (0, "up", "north"):
+        # Decrease the y position
+        cursor[0] -= 1
+
+    elif direction in (1, "right", "east"):
+        # Increase the x position
+        cursor[1] += 1
+
+    elif direction in (2, "down", "south"):
+        # Increase the y position
+        cursor[0] += 1
+
+    elif direction in (3, "left", "west"):
+        # Decrease the x position
+        cursor[1] -= 1
+
+    return cursor
+
+
+def cursor_move(screen, cursor: list):
+    # Moves the cursor to anywhere on the screen
+    screen.move(cursor[0], cursor[1])

core/modes.py

@@ -0,0 +1,33 @@
+from mode import normal, insert, command
+
+
+def activate(instance, mode) -> object:
+    # Visibly update the mode
+    instance.mode = mode
+    instance.update()
+
+    if mode == "command":
+        instance = command.activate(instance)
+
+    elif mode == "insert":
+        instance = insert.activate(instance)
+
+    elif mode == "normal":
+        instance = normal.activate(instance)
+
+    return instance
+
+
+def handle_key(instance, key):
+    if instance.mode == "normal":
+        instance = normal.execute(instance, key)
+
+    # Insert mode - inserting text to the buffer
+    elif instance.mode == "insert":
+        instance = insert.execute(instance, key)
+
+    # Command mode - extra commands for lambda
+    elif instance.mode == "command":
+        instance = command.activate(instance)
+
+    return instance

core/utils.py

@@ -1,51 +1,109 @@
-from sys import exit
 import curses
+import sys
 
 
-def refresh_window_size(screen, data):
+def clear(instance, y: int, x: int):
-    # Get the height and width of the screen
+    # Clear the line at the screen at position y, x
-    data["height"], data["width"] = screen.getmaxyx()
+    instance.screen.insstr(y, x, " " * (instance.width - x))
-
-    # Return the data as changes may have been made
-    return data
 
 
-def clear_line(screen, data, line):
+def welcome(screen):
-    # Clear the specified line
+    # Get window height and width
-    screen.addstr(line, 0, " " * (data["width"] - 1), curses.color_pair(1))
+    height, width = screen.getmaxyx()
+
+    # Startup text
+    title = "λ Lambda"
+    subtext = [
+        "Next generation hackable text editor for nerds",
+        "",
+        "Type :h to open the README.md document",
+        "Type :o <file> to open a file and edit",
+        "Type :q or <C-c> to quit lambda.py"
+    ]
+
+    # Centering calculations
+    start_x_title = int((width // 2) - (len(title) // 2) - len(title) % 2)
+    start_y = int((height // 2) - 2)
+
+    # Rendering title
+    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)
+        screen.addstr(start_y, start_x, text)
 
 
-def prompt(screen, data, text):
+def prompt(instance, message: str, color: int = 1) -> (list, None):
-    # Print the prompt
+    # Initialise the input list
-    screen.addstr(data["height"] - 1, 0, text, curses.color_pair(11))
+    inp = []
 
-    # Wait for and capture a key press from the user
+    # Write the message to the screen
-    return screen.getch()
+    instance.screen.addstr(instance.height - 1, 0, message, curses.color_pair(color))
+
+    while True:
+        # Wait for a keypress
+        key = instance.screen.getch()
+
+        # Subtracting a key (backspace)
+        if key in (curses.KEY_BACKSPACE, 127, '\b'):
+            # Write whitespace over characters to refresh it
+            clear(instance, instance.height - 1, 0)
+
+            if inp:
+                # Subtract a character from the input list
+                inp.pop()
+
+            else:
+                # Exit the prompt without returning the input
+                return None
+
+        elif key == 27:
+            # Exit the prompt, without returning the input
+            return None
+
+        elif key in (curses.KEY_ENTER, ord('\n'), ord('\r'), ord(":"), ord(";")):
+            # Return the input list
+            return inp
+
+        else:
+            # If any other key is typed, append it
+            # As long as the key is in the valid list
+            valid = "abcdefghijklmnopqrstuvwxyz ABCDEFGHIJKLMNOPQRSTUVWXYZ!"
+            if chr(key) in valid and len(inp) < (instance.width - 2):
+                inp.append(chr(key))
+
+        # Write the message to the screen
+        instance.screen.addstr(instance.height - 1, 0, message, curses.color_pair(color))
+
+        # Join the input together for visibility on the screen
+        input_text = "".join(inp)
+
+        # Write the input text to the screen
+        instance.screen.addstr(instance.height - 1, len(message), input_text)
 
 
-def goodbye(screen, data):
+def goodbye(instance):
-    # Create a goodbye prompt
+    choice = prompt(instance, "Really quit lambda? (y/n): ", 11)
-    key = prompt(screen, data, "Really quit? (y or n): ")
+    if choice and choice[0] == "y":
+        curses.endwin()
+        sys.exit()
 
-    # Clear the bottom line
+    else:
-    clear_line(screen, data, data["height"] - 1)
+        clear(instance, instance.height - 1, 0)
-
-    if key == ord("y"):
-        # Only exit if the key was "y", a confirmation
-        exit()
-
-    # Clear the bottom line again
-    clear_line(screen, data, data["height"] - 1)
 
 
-def error(screen, data, error_msg):
+def error(instance, message: str):
-    # Print the error message to the bottom line
+    # Parse the error message
-    error_msg = f"ERROR: {error_msg}"
+    error_message = f"ERROR: {message}"
-    screen.addstr(data["height"] - 1, 0, error_msg, curses.color_pair(3))
-    screen.addstr(data["height"] - 1, len(error_msg) + 1, "(press any key) ", curses.color_pair(1))
 
-    # Wait for a key to be pressed
+    # Write the entire message to the screen
-    screen.getch()
+    instance.screen.addstr(instance.height - 1, 0, f"ERROR: {message}", curses.color_pair(3))
+    instance.screen.addstr(instance.height - 1, len(error_message) + 1, f"(press any key)")
 
-    # Clear the bottom line
+    # Wait for a keypress
-    clear_line(screen, data, data["height"] - 1)
+    instance.screen.getch()
+
+    # Clear the bottom of the screen
+    clear(instance, instance.height - 1, 0)

main.py

@@ -0,0 +1,110 @@
+from core import colors, cursors, buffers, modes, utils
+from core.buffers import Buffer
+from core.components import Components
+import traceback
+import argparse
+import curses
+import sys
+import os
+
+
+class Lambda:
+    def __init__(self, buffer: Buffer):
+        self.screen = curses.initscr()
+        self.buffer = buffer
+        self.cursor = [0, 0]
+        self.mode = "normal"
+        self.components = Components()
+        self.height = self.screen.getmaxyx()[0]
+        self.width = self.screen.getmaxyx()[1]
+        self.safe_height = self.height - len(self.components.components["bottom"])
+        self.config = {"icon": "λ"}
+
+    def update_dimensions(self):
+        self.height, self.width = self.screen.getmaxyx()
+        self.safe_height = self.height - len(self.components.components["bottom"])
+
+    def update(self):
+        # Update the dimensions
+        self.update_dimensions()
+
+        # Refresh the on-screen components
+        self.components.render(self)
+
+        # Move the cursor
+        cursors.cursor_move(self.screen, self.cursor)
+
+    def start(self):
+        # Initialise colors
+        colors.init_colors()
+
+        # Change the cursor shape
+        cursors.cursor_mode("block")
+
+        # Turn no echo on
+        curses.noecho()
+
+        # Show a welcome message if lambda opens with no file
+        if not self.buffer.path:
+            utils.welcome(self.screen)
+
+        # Main loop
+        self.run()
+
+    def run(self):
+        while True:
+            # Write the buffer to the screen
+            # buffers.write_buffer(screen, buffer)
+
+            # Update the screen
+            self.update()
+
+            # Wait for a keypress
+            key = self.screen.getch()
+
+            # Handle the key
+            modes.handle_key(self, key)
+
+            # Refresh and clear the screen
+            self.screen.refresh()
+            self.screen.clear()
+
+
+def main():
+    # Command line arguments
+    parser = argparse.ArgumentParser(description="Next generation hackable text editor for nerds.")
+    parser.add_argument("file", metavar="file", type=str, nargs="?",
+                        help="The name of a file for lambda to open")
+
+    # Collect the arguments passed into lambda
+    args = parser.parse_args()
+
+    # Load the file into buffer
+    buffer = buffers.load_file(args.file)
+
+    # Change the escape delay to 25ms
+    # Fixes an issue where esc takes way too long to press
+    os.environ.setdefault("ESCDELAY", "25")
+
+    # Load lambda with the buffer
+    screen = Lambda(buffer)
+
+    # Start the screen
+    try:
+        screen.start()
+
+    # KeyboardInterrupt is thrown when ctrl+c is pressed
+    except KeyboardInterrupt:
+        curses.endwin()
+        sys.exit()
+
+    except Exception as exception:
+        curses.endwin()
+        print(f"{colors.Codes.red}FATAL ERROR:{colors.Codes.end} "
+              f"{colors.Codes.yellow}{exception}{colors.Codes.end}\n")
+        print(traceback.format_exc())
+        sys.exit(0)
+
+
+if __name__ == "__main__":
+    main()

mode/command.py

@@ -0,0 +1,34 @@
+from core import utils
+
+
+def execute(instance, commands):
+    if not commands:
+        # Quit if there are no commands, don't check anything
+        return instance
+
+    for command in commands:
+        if command == "w":
+            # Write to the file
+            pass
+
+        elif command == "q":
+            # Load a goodbye prompt
+            utils.goodbye(instance)
+
+        else:
+            utils.error(instance, f"not an editor command: '{command}'")
+
+    return instance
+
+
+def activate(instance):
+    # Start the prompt
+    commands = utils.prompt(instance, ":")
+
+    # Execute the commands
+    instance = execute(instance, commands)
+
+    # Return to normal mode
+    instance.mode = "normal"
+
+    return instance

mode/insert.py

@@ -0,0 +1,18 @@
+from core import cursors
+from mode import normal
+
+
+def execute(instance, key):
+    if key == 27:
+        # Switch to normal mode
+        instance.mode = "normal"
+        normal.activate(instance)
+
+    return instance
+
+
+def activate(instance):
+    # Switch the cursor to a line
+    cursors.cursor_mode("line")
+
+    return instance

mode/normal.py

@@ -0,0 +1,45 @@
+from core import cursors, modes
+from mode import insert
+from mode import command
+
+
+def execute(instance, key):
+    if key == ord("j"):
+        # Move the cursor down
+        instance.cursor = cursors.cursor_push(instance.cursor, "down")
+
+    elif key == ord("k"):
+        # Move the cursor up
+        instance.cursor = cursors.cursor_push(instance.cursor, "up")
+
+    elif key == ord("l"):
+        # Move the cursor right
+        instance.cursor = cursors.cursor_push(instance.cursor, "right")
+
+    elif key == ord("h"):
+        # Move the cursor left
+        instance.cursor = cursors.cursor_push(instance.cursor, "left")
+
+    elif key == ord("i"):
+        # Activate insert mode
+        instance = modes.activate(instance, "insert")
+
+    elif key == ord("I"):
+        # Move the cursor to the right
+        instance.cursor = cursors.cursor_push(instance.cursor, "right")
+
+        # Then activate insert mode
+        instance = modes.activate(instance, "insert")
+
+    elif key in (ord(":"), ord(";")):
+        # Activate command mode
+        instance = modes.activate(instance, "command")
+
+    return instance
+
+
+def activate(instance):
+    # Switch the cursor to a block
+    cursors.cursor_mode("block")
+
+    return instance