Re: Tools to help with text mode (i.e. non-GUI) input

Chris Green <cl@isbd.net> wrote or quoted:

Are there any packages that offer this sort of thing? I'd prefer ones
from the Debian repositories but that's not absolutely necessary.

  So, in my humble opinion, it's a no-brainer to split this into two
  camps and draw a line between Linux and Windows.

  On Linux, you're going to wanna roll with curses. See [1] below.

  For Windows, whip up your own terminal using tkinter (Yeah,
  tkinter's a GUI library, no doubt! But in this case, it's just
  being used to mimic a terminal.) as your secret sauce. See [2].

  If that's too tied to specific systems for your taste,
  why not cook up a library that smooths out those wrinkles?

  The following drafts still contain bugs, but might convey
  the idea.

  [1]

import curses

def main(stdscr):
    # Clear screen and hide cursor
    stdscr.clear()
    curses.curs_set(1)

    # Display prompt
    stdscr.addstr(0, 0, "Color? ")
   
    # Pre-fill with "red"
    default_text = "red"
    stdscr.addstr(0, 7, default_text)
   
    curses.echo()  # Enable echo of characters
    curses.cbreak()  # React to keys instantly without Enter key

    # Initialize cursor position
    cursor_x = 7 + len(default_text)
    current_text = default_text

    while True:
        stdscr.move(0, cursor_x)
        ch = stdscr.getch()

        if ch == ord('\n'):  # Enter key
            break
        elif ch in (curses.KEY_BACKSPACE, 127):  # Backspace
            if cursor_x > 7:
                cursor_x -= 1
                current_text = current_text[:cursor_x-7] + current_text[cursor_x-6:]
                stdscr.delch(0, cursor_x)
        elif ch == curses.KEY_LEFT:
            if cursor_x > 7:
                cursor_x -= 1
        elif ch == curses.KEY_RIGHT:
            if cursor_x < 7 + len(current_text):
                cursor_x += 1
        elif 32 <= ch <= 126:  # Printable characters
            current_text = current_text[:cursor_x-7] + chr(ch) + current_text[cursor_x-7:]
            stdscr.insch(0, cursor_x, ch)
            cursor_x += 1

        stdscr.refresh()

    # Clear screen
    stdscr.clear()

    # Display result
    stdscr.addstr(0, 0, f"You entered: {current_text}")
    stdscr.refresh()
    stdscr.getch()

if __name__ == "__main__":
    curses.wrapper(main)

  [2]

import tkinter as tk
from tkinter import simpledialog

class ColorQueryApp:
    def __init__(self, master):
        self.master = master
        master.title("Color Query")

        # Create the Text widget
        self.text_field = tk.Text(master, height=10, width=40)
        self.text_field.pack(padx=10, pady=10)

        # Create a button to add new color queries
        self.add_button = tk.Button(master, text="Add Color Query", command=self.add_color_query)
        self.add_button.pack(pady=5)

        # Bind the Return key event
        self.text_field.bind('<Return>', self.show_color_dialog)

    def add_color_query(self):
        # Insert a new line if the Text widget is not empty
        if self.text_field.index('end-1c') != '1.0':
            self.text_field.insert('end', '\n')

        # Insert the new color query line
        query_line = "Color? red"
        self.text_field.insert('end', query_line)

        # Move the cursor to the end of the new line
        self.text_field.mark_set('insert', f'{self.text_field.index("end-1c")}')

        # Bind the key events
        self.text_field.bind('<Key>', self.check_editing)

    def check_editing(self, event):
        # Allow all keystrokes if cursor is in editable area
        if self.text_field.compare('insert', '>=', 'insert linestart+7c'):
            return

        # Prevent editing in the "Color? " area
        if event.keysym in ['BackSpace', 'Delete'] or len(event.char) > 0:
            return 'break'

    def show_color_dialog(self, event):
        # Get the current line
        current_line = self.text_field.get("insert linestart", "insert lineend")
       
        # Extract the color
        color = current_line[7:].strip()
       
        # Show a dialog with the entered color
        simpledialog.messagebox.showinfo("Entered Color", f"You entered: {color}")
       
        # Prevent the default newline behavior
        return 'break'

root = tk.Tk()
app = ColorQueryApp(root)
root.mainloop()