Detect if Unicode box characters are supported in user's locale (fixes 295)

sebastinas · sebastinas · commit a5e541bf092a · 2015-01-29T21:10:07.000+01:00
Signed-off-by: Sebastian Ramacher &lt;sebastian+dev@ramacher.at&gt;
diff --git a/bpython/cli.py b/bpython/cli.py
@@ -72,7 +72,7 @@
 from bpython import importcompletion
 
 # This for config
-from bpython.config import Struct
+from bpython.config import Struct, getpreferredencoding
 
 # This for keys
 from bpython.keys import cli_key_dispatch as key_dispatch
@@ -98,9 +98,6 @@
 # ---
 
 
-def getpreferredencoding():
-    return locale.getpreferredencoding() or sys.getdefaultencoding()
-
 def calculate_screen_lines(tokens, width, cursor=0):
     """Given a stream of tokens and a screen width plus an optional
     initial cursor position, return the amount of needed lines on the
diff --git a/bpython/config.py b/bpython/config.py
@@ -3,11 +3,11 @@
 from __future__ import with_statement
 import os
 import sys
+import locale
 from ConfigParser import ConfigParser
 from itertools import chain
 from bpython.keys import cli_key_dispatch as key_dispatch
 from bpython.autocomplete import SIMPLE as default_completion
-
 import bpython.autocomplete
 
 
@@ -16,6 +16,21 @@ class Struct(object):
     to and use for various arbitrary things."""
 
 
+def getpreferredencoding():
+    """Get the user's preferred encoding."""
+    return locale.getpreferredencoding() or sys.getdefaultencoding()
+
+
+def supports_box_chars():
+    """Check if the encoding suppors Unicode box characters."""
+    try:
+        for c in (u'│', u'│', u'─', u'─', u'└', u'┘', u'┌', u'┐'):
+            c.encode(getpreferredencoding())
+        return True
+    except UnicodeEncodeError:
+        return False
+
+
 def get_config_home():
     """Returns the base directory for bpython's configuration files."""
     xdg_config_home = os.environ.get('XDG_CONFIG_HOME', '~/.config')
@@ -256,7 +271,7 @@ def get_key_no_doublebind(command):
         struct.autocomplete_mode = default_completion
 
     # set box drawing characters
-    if config.getboolean('general', 'unicode_box'):
+    if config.getboolean('general', 'unicode_box') and supports_box_chars():
         struct.left_border = u'│'
         struct.right_border = u'│'
         struct.top_border = u'─'
diff --git a/bpython/inspection.py b/bpython/inspection.py
@@ -1,6 +1,6 @@
 # The MIT License
 #
-# Copyright (c) 2009-2011 the bpython authors.
+# Copyright (c) 2009-2015 the bpython authors.
 #
 # Permission is hereby granted, free of charge, to any person obtaining a copy
 # of this software and associated documentation files (the "Software"), to deal

Original file line number	Diff line number	Diff line change
`@@ -1,6 +1,6 @@`
`1`	`1`	`# The MIT License`
`2`	`2`	`#`
`3`		`-# Copyright (c) 2009-2011 the bpython authors.`
	`3`	`+# Copyright (c) 2009-2015 the bpython authors.`
`4`	`4`	`#`
`5`	`5`	`# Permission is hereby granted, free of charge, to any person obtaining a copy`
`6`	`6`	`# of this software and associated documentation files (the "Software"), to deal`