Remove commented code

This makes it easier to track what's happening in the function

tilde-train.py

@@ -1,57 +1,57 @@
 #!/usr/bin/env python3
 
-##  _   _ _    _      _            _
-## | |_(_) |__| |___ | |_ _ _ __ _(_)_ _
-## |  _| | / _` / -_)|  _| '_/ _` | | ' \
-## \__|_|_\__,_\___(_)__|_| \__,_|_|_||_|
-##
-## tilde.train is an instance of TerminalTrain.  It was originally developed
-## by cmccabe on tilde.town (https://tildegit.org/cmccabe/TerminalTrain) but is now
-## maintained by vilmibm.
-##
-## If you want to contribute code improvements, create a pull request here:
-## https://git.tilde.town/vilmibm/tilde-train
-##
-## -----------------
-##
-## WHAT IS IT?
-## like sl (the ls typo prank), but each car on the train is a x*y character ascii art
-## produced by tilde.town.
-##
-## ( original sl source code of sl?   https://github.com/mtoyoda/sl )
-##
-## TODO:
-##       * loosen the restriction on allowable characters in train cars.  right now, limited
-##         to characters in python's string.printable list.
-##       * turn main loop into a function, so cmd line arg reader can call it (with -p) and quit.
-##       * figure out why tilde.train doesn't work in some terminals (sthg sthg unicode...)
-##       * BUGFIX-1 - something about inclusion default cars adding extra "links" to the train.
-##       * the -p (print train) option should print all cars, not limited to the max_cars value.
-##       * related to BUGFIX-1, that seems to impact spacers (links) between cars.
-##       * allow users to create multiple frames so their cars can be animated (difficulty=med+)
-##       * allow user configurable speed and number of train cars
-##       * allow users to move the train up or down with arrow keys
-##         -- worked with asciimatics, but python curses blocks on getch()
-##
+#  _   _ _    _      _            _
+# | |_(_) |__| |___ | |_ _ _ __ _(_)_ _
+# |  _| | / _` / -_)|  _| '_/ _` | | ' \
+# \__|_|_\__,_\___(_)__|_| \__,_|_|_||_|
+#
+# tilde.train is an instance of TerminalTrain.  It was originally developed
+# by cmccabe on tilde.town (https://tildegit.org/cmccabe/TerminalTrain) but is now
+# maintained by vilmibm.
+#
+# If you want to contribute code improvements, create a pull request here:
+# https://git.tilde.town/vilmibm/tilde-train
+#
+# -----------------
+#
+# WHAT IS IT?
+# like sl (the ls typo prank), but each car on the train is a x*y character ascii art
+# produced by tilde.town.
+#
+# ( original sl source code of sl?   https://github.com/mtoyoda/sl )
+#
+# TODO:
+#       * loosen the restriction on allowable characters in train cars.  right now, limited
+#         to characters in python's string.printable list.
+#       * turn main loop into a function, so cmd line arg reader can call it (with -p) and quit.
+#       * figure out why tilde.train doesn't work in some terminals (sthg sthg unicode...)
+#       * BUGFIX-1 - something about inclusion default cars adding extra "links" to the train.
+#       * the -p (print train) option should print all cars, not limited to the max_cars value.
+#       * related to BUGFIX-1, that seems to impact spacers (links) between cars.
+#       * allow users to create multiple frames so their cars can be animated (difficulty=med+)
+#       * allow user configurable speed and number of train cars
+#       * allow users to move the train up or down with arrow keys
+#         -- worked with asciimatics, but python curses blocks on getch()
+#
 
-from random import shuffle ## allowing us to randomize selection of cars.
-import glob  ## allowing us to search the file system for .choochoo files.
-import sys ## so we can read command line arguments.
-import getpass ## so we can get the user's username
+from random import shuffle # allowing us to randomize selection of cars.
+import glob  # allowing us to search the file system for .choochoo files.
+import sys # so we can read command line arguments.
 import curses
 from signal import signal, SIGINT
-import time ## allowing the loop steps of train animation to be slowed
-import string ## for input validation
+import time # allowing the loop steps of train animation to be slowed
+import string # for input validation
 from inspect import cleandoc
+from pathlib import Path
 
 traincarFN = ".choochoo"
-max_x = 35  ## max length of train car.
-max_y = 10  ## max height of train car.
-max_cars = 10 ## most cars to include in one train.
-print_train = False ## print train to file (instead of the screen scroll)
+max_x = 35  # max length of train car.
+max_y = 10  # max height of train car.
+max_cars = 10 # most cars to include in one train.
+print_train = False # print train to file (instead of the screen scroll)
 
-train = [""]*max_y ## empty train of correct height.
-cars = []
+train = [""]*max_y # empty train of correct height.
+cars: list[list[str]] = []
 
 engine = [
   r"        ____                      ",
@@ -122,23 +122,22 @@ def print_help():
 
 
 def test_user_car():
-  username = getpass.getuser()
-  fname = "/home/" + username + "/" + traincarFN
+  fname = Path.home() / traincarFN
   try:
-    myfile =  open(fname, 'r')
-  except:
-    print("ERROR: Couldn't open " + fname)
-    print("Either it doesn't exist, or is not readble by the tilde.train script.")
-    sys.exit(1)
+    choochoo_string = fname.read_text("utf-8")
+  except OSError as err:
+    raise OSError(
+      f"Couldn't open {fname}\n"
+      "Either it doesn't exist, or is not readble by the tilde.train script."
+    ) from err
 
-  choochoo_string = myfile.read()
   choochoo_list = choochoo_string.split("\n")
 
   car = "\n".join(choochoo_list)
-  car2 = car.replace("\t", "") ## do not allow tabs
-  car2 = car2.replace("\v", "") ## do not allow vertical tabs
-  car2 = car2.replace("\f", "") ## do not allow line feeds
-  car2 = car2.replace("\r", "") ## do not allow carriage returns
+  car2 = car.replace("\t", "") # do not allow tabs
+  car2 = car2.replace("\v", "") # do not allow vertical tabs
+  car2 = car2.replace("\f", "") # do not allow line feeds
+  car2 = car2.replace("\r", "") # do not allow carriage returns
   car2 = ''.join([i if string.printable.find(i) >= 0 else ' ' for i in car2])
 
   print("")
@@ -168,99 +167,90 @@ def test_user_car():
     print("Yours contained " + bad_chars)
     sys.exit(1)
 
-#  print("")
-#  print("Test results:")
-
   train_height = len(choochoo_list)
   train_length = len(max(choochoo_list, key=len))
 
   if train_height > max_y+1:
     print("FAIL. Your train car is too tall.")
     print("It should be no taller than " + str(max_y) + " lines in height.")
-    myfile.close()
     sys.exit(1)
 
   if train_length > max_x:
     print("FAIL. Your train car is too long.")
     print("It should be no longer than " + str(max_x) + " characters in length.")
-    myfile.close()
     sys.exit(1)
 
   print("PASS. Your train car will work on the tilde.town tracks! :)")
-  myfile.close()
   sys.exit()
 
-def link_car(car):
+def link_car(car: list[str]):
   for idx,row in enumerate(car):
     car[idx] = " " + row
   car[len(car)-3] = "+" + car[len(car)-3][1:]
   car[len(car)-2] = "+" + car[len(car)-2][1:]
   return car
 
-def validate_car(car):
-## this function (1) checks that a train car isn't too tall or too long
-## (2) pads it vertically or on the right side if it is too short or if
-## not all lines are the same length and (3) removes bad characters.
+def validate_car(car: list[str]):
+# this function (1) checks that a train car isn't too tall or too long
+# (2) pads it vertically or on the right side if it is too short or if
+# not all lines are the same length and (3) removes bad characters.
 
-  car = "\n".join(car)
-  car = ''.join([i if ord(i) < 128 else ' ' for i in car])
-  car = car.split("\n")
+  car_str = "\n".join(car)
+  car_str = ''.join([i if ord(i) < 128 else ' ' for i in car_str])
+  car_list = car_str.split("\n")
 
-  ## remove blank lines from top and bottom of car,
-  ## so we can estimate its true size.
-  while car[0].strip() == "":
-    car.pop(0) ## clear top
-  while car[(len(car)-1)].strip() == "":
-    car.pop() ## clear bottom
+  # remove blank lines from top and bottom of car,
+  # so we can estimate its true size.
+  while car_list[0].strip() == "":
+    car_list.pop(0) # clear top
+  while car_list[(len(car_list)-1)].strip() == "":
+    car_list.pop() # clear bottom
 
-  ## len(choochoo_list) is the height of the train car, in number of rows.
-  if len(car) > max_y+1 or len(car) == 0:
-    return 0  ## train car too tall or non-existant; skip it.
+  # len(choochoo_list) is the height of the train car, in number of rows.
+  if len(car_list) > max_y+1 or len(car_list) == 0:
+    return 0  # train car too tall or non-existant; skip it.
 
-  ## vertically pad short cars with 1 space (lines will be lengthened later).
-  while len(car) < max_y:
-    car = [" "] + car
+  # vertically pad short cars with 1 space (lines will be lengthened later).
+  while len(car_list) < max_y:
+    car_list = [" "] + car_list
 
-  for idx,row in enumerate(car):
-    car[idx] = row.rstrip()
+  for idx,row in enumerate(car_list):
+    car_list[idx] = row.rstrip()
 
-  longest_line = len(max(car, key=len)) ## longest line in .choochoo file.
+  longest_line = len(max(car_list, key=len)) # longest line in .choochoo file.
 
-  for idx,row in enumerate(car):
-    if len(row) > max_x+1: ## check length of each row in .choochoo file.
-      return 0 ## train car too long; skip it.
+  for idx,row in enumerate(car_list):
+    if len(row) > max_x+1: # check length of each row in .choochoo file.
+      return 0 # train car too long; skip it.
     elif "\t" in row or "\v" in row or "\f" in row or "\r" in row:
       return 0 # skip if contains tabs, vert tabs, line feeds or carriage ret
     elif len(row) < longest_line:
       padding = " "*(longest_line - len(row))
-      car[idx] += padding ## add padding spaces.
+      car_list[idx] += padding # add padding spaces.
 
-  return car
+  return car_list
 
 
 def print_all_cars():
   for fname in glob.glob('/home/*/' + traincarFN):
     try:
       with open(fname, 'r') as myfile:
-        ## print fname ## debug, print file path and name
         choochoo_string = myfile.read()
         choochoo_list = choochoo_string.split("\n")
       if len(choochoo_list) > max_y+1:
-        continue ## the train car was too tall; skip it.
+        continue # the train car was too tall; skip it.
 
-      car = validate_car(choochoo_list) ## printing is only a DEBUG feature.
+      car = validate_car(choochoo_list) # printing is only a DEBUG feature.
       if car != 0:
         print("")
         print(fname + ":")
-        print("\n".join(car)) ## print the car to stdout
+        print("\n".join(car)) # print the car to stdout
 
-      ## HOW TO CLOSE THE FILE HANDLE? fname.close(), close(fname), ...?
     except:
       pass;
-#      print "Cannot open " + fname # for debuggering purposes
 
 
-def chuggachugga(stdscr):
+def chuggachugga(stdscr: curses.window):
   curses.curs_set(0)
   h, w = stdscr.getmaxyx()
   x_pos = w-1
@@ -268,37 +258,19 @@ def chuggachugga(stdscr):
 
   while True:
     for idx,train_layer in enumerate(reversed(train)):
-#      screen.print_at(train_layer, x_pos, (y_pos-idx))
-#      stdscr.addstr((y_pos-idx),x_pos,train_layer)
 
       train_snip_start = 0 if (x_pos >= 0) else min(abs(x_pos), len(train_layer))
       train_snip_end = w-x_pos if (w-x_pos <= len(train_layer)) else len(train_layer)
-#      train_snip_end = min(len(train_layer),w-x_pos)
       x = max(0, x_pos)
-#      stdscr.addstr(2,2,"start: " + str(train_snip_start))
-#      stdscr.addstr(3,2,"end: "+ str(train_snip_end))
-#      stdscr.addstr(4,2,"x_pos: " + str(x_pos))
-#      stdscr.addstr(5,2,"train len: " + str(len(train_layer)))
       stdscr.addstr((y_pos-idx),x,train_layer[train_snip_start:train_snip_end])
 
     x_pos -= 1
     if x_pos == -train_len:
-#      stdscr.addstr(2,5,"here we are!")
-#      time.sleep(10)
       return
 
     stdscr.refresh()
     time.sleep(.03)
 
-#    ev = stdscr.getch() ## seems like curses waits for input, which won't work here.
-#    if ev in (ord('Q'), ord('q')):
-#      return
-#    elif ev == curses.KEY_UP: ## up
-#      y_pos += 1
-#    elif ev == curses.KEY_DOWN: ## down
-#      y_pos -= 1
-
-
 def handler(signal_received, frame):
   print("Oops. The train broke.  The engineer is looking into it!")
   print("(Note: the train does not work in all terminals yet.)")
@@ -322,28 +294,26 @@ if len(sys.argv) == 2 and ("-a" in sys.argv[1] or "all" in sys.argv[1]):
   sys.exit()
 
 
-## start a loop that collects all .choochoo files and processes on in each loop
+# start a loop that collects all .choochoo files and processes on in each loop
 for fname in glob.glob('/home/*/' + traincarFN):
   car_len = 1
   try:
     with open(fname, 'r') as myfile:
-      ## print fname ## debug, print file path and name
+      # print fname # debug, print file path and name
       choochoo_string = myfile.read()
       choochoo_list = choochoo_string.split("\n")
     if len(choochoo_list) > max_y+1:
-      continue ## the train car was too tall; skip it.
+      continue # the train car was too tall; skip it.
 
-    car = validate_car(choochoo_list) ## printing is only a DEBUG feature.
+    car = validate_car(choochoo_list) # printing is only a DEBUG feature.
     if car != 0:
-      cars.append(car) ## start a list of lists (list of cars) here.
+      cars.append(car) # start a list of lists (list of cars) here.
 
-    ## HOW TO CLOSE THE FILE HANDLE? fname.close(), close(fname), ...?
   except:
     pass;
-    ##print "Cannot open " + fname # for debuggering purposes
 
 while len(cars) < max_cars:
-  cars.append(default_car) ## add default cars if train too short
+  cars.append([*default_car]) # add copies of default cars if train too short
 
 shuffle(cars)
 cars = cars[0:max_cars]