Merge pull request #46 from solvebio/feature/ipython-notebook-and-iss…

…ues-21-43

Address issue #43 and possibly #21

solvebio/utils/printing.py

@@ -7,14 +7,37 @@
 
 logger = logging.getLogger('solvebio')
 
+std_handles = [sys.stdin, sys.stdout, sys.stderr]
 try:
+    # Switch from the default input ASCII encoding to the default locale.
+    # The Python runtime will use this when it has to decode a
+    # string buffer to unicode. This is not needed in Python3.
+
+    # However reload(sys), used below resets stdin, stdout, and stderr
+    # which is bad if they've already been reassigned. An ipython
+    # notebook shell, for example, sets up its own stdout.
+    # See github issue #43 and #21.
     reload(sys).setdefaultencoding(locale.getdefaultlocale()[1])
     locale.setlocale(locale.LC_ALL, '')
 except:
     pass
+finally:
+    sys.stdin, sys.stdout, sys.stderr = std_handles
+
+
+# Set rows and columns and colors
+
+
+def set_from_env(name, default_value):
+    try:
+        return int(os.environ[name])
+    except:
+        return default_value
+
+
+TTY_ROWS = set_from_env('LINES', 24)
+TTY_COLS = set_from_env('COLUMNS', 80)
 
-TTY_ROWS = 24
-TTY_COLS = 80
 TTY_COLORS = True
 
 if sys.stdout.isatty():
@@ -26,7 +49,8 @@
             TTY_ROWS = int(rows)
             TTY_COLS = int(cols)
     except:
-        logger.warn('Cannot detect terminal column width')
+        logger.warn('Cannot detect terminal column width.\nUsing value '
+                    'from environment variables and/or internal defaults.')
 else:
     TTY_COLORS = False