fix #3 encoding and other issues

.gitignore

@@ -9,3 +9,4 @@ rnd
 help/html
 help/docal.chm
 help/toc.hhc
+.venv

docal_tkinter/app.py

@@ -1,5 +1,5 @@
-# -{cd .. | python -m docal_tkinter}
-from tkinter import Tk, Menu
+# $ cd .. && python -m docal_tkinter
+from tkinter import Tk
 from .sidebar import Sidebar
 from .worksheet import Worksheet
 from .menubar import Menubar

docal_tkinter/menubar.py

@@ -1,11 +1,12 @@
-# -{cd .. | python -m docal_tkinter}
 from tkinter import Menu, filedialog, messagebox, Toplevel, Label
 from json import dump, loads, dumps
 from docal.parsers.excel import parse as parse_xl
 from docal.parsers.dcl import to_py
-from os import path, startfile
+from os import path
 from webbrowser import open_new_tab
 
+from docal_tkinter.sidebar import start_file
+
 class Menubar(Menu):
     def __init__(self, master):
         super().__init__(master, tearoff=0)
@@ -72,7 +73,7 @@ def open(self, filename=None):
             if not self.new(): return
         ext = path.splitext(filename)[1]
         self.worksheet.frame.grid_slaves()[0].destroy()  # start from scratch
-        with open(filename) as file:
+        with open(filename, encoding='utf-8') as file:
             in_file = file.read()
         if ext == '.dcl':
             data = loads(in_file)
@@ -195,7 +196,7 @@ def __init__(self, master):
         self.add_command(label='About', command=self.about)
 
     def help(self):
-        startfile('docal.chm')
+        start_file('docal.chm')
 
     def about(self):
         win = Toplevel()

docal_tkinter/sidebar.py

@@ -1,12 +1,21 @@
-# -{cd .. | python -m docal_tkinter}
-from tkinter.ttk import Frame, Label, Entry, Button, Labelframe, OptionMenu, Label
+from tkinter.ttk import Frame, Entry, Button, Labelframe
 from tkinter import filedialog, messagebox, StringVar
-from os import startfile, path
+import os
+import sys
+import subprocess
+from os import path
 
 from docal import processor
 from docal.document import word, latex
 from docal.parsers.dcl import parse
 
+def start_file(filename):
+    if sys.platform == "win32":
+        os.startfile(filename)
+    else:
+        opener = "open" if sys.platform == "darwin" else "xdg-open"
+        subprocess.call([opener, filename])
+
 class Sidebar(Frame):
     def __init__(self, master):
         super().__init__(master, borderwidth='.25cm')
@@ -113,7 +122,7 @@ def open_file(self, which):
                 return
             filename = self.outfile.get()
         try:
-            startfile(filename)
+            start_file(filename)
         except OSError as err:
             messagebox.showerror('Error', err.args[1])