Changing input filtering to require whitespace separation between the initial command (alias, magic, autocall) and rest of line.

This fixes some subtle but nasty bugs with lines that start with,
e.g. r'a_string'.  They had been getting parsed as the magic %r followed by
the string literal 'a_string' -- now that's been fixed.

IPython/prefilter.py

@@ -105,7 +105,7 b' def splitUserInput(line, pattern=None):'
 
     #print 'line:<%s>' % line # dbg
     #print 'pre <%s> iFun <%s> rest <%s>' % (pre,iFun.strip(),theRest) # dbg
-    return pre,iFun.strip(),theRest
+    return pre,iFun.strip(),theRest.lstrip()
 
 
 # RegExp for splitting line contents into pre-char//first word-method//rest.
@@ -122,10 +122,10 b' def splitUserInput(line, pattern=None):'
 # The three parts of the regex are:
 #  1) pre:     pre_char *or* initial whitespace 
 #  2) iFun:    first word/method (mix of \w and '.')
-#  3) theRest: rest of line
+#  3) theRest: rest of line (separated from iFun by space if non-empty)
 line_split = re.compile(r'^([,;/%?]|!!?|\s*)'
-                        r'\s*([\w\.]+)\s*'
-                        r'(.*)$')
+                        r'\s*([\w\.]+)'
+                        r'(\s+.*$|$)')
 
 shell_line_split = re.compile(r'^(\s*)(\S*\s*)(.*$)')
 

test/test_handlers.py

@@ -17,7 +17,8 b' def run(tests):'
         ip.runlines(pre)
         ip.runlines('_i')  # Not sure why I need this...
         actual = ip.user_ns['_i']
-        if actual != None: actual = actual.rstrip('\n')
+        if actual != None:
+            actual = actual.rstrip('\n')
         if actual != post:
             failures.append('Expected %r to become %r, found %r' % (
                 pre, post, actual))
@@ -53,8 +54,8 b' try:'
     # write anything to stdout.
 
     # Turn off actual execution of aliases, because it's noisy
-    old_system_cmd = ip.IP.system
-    ip.IP.system = lambda cmd: None
+    old_system_cmd = ip.system
+    ip.system = lambda cmd: None
     
     
     ip.IP.alias_table['an_alias'] = (0, 'true')
@@ -66,7 +67,7 b' try:'
          # chars, *not* initial chars which happen to be aliases:
          ("top",         '_ip.system("d:/cygwin/top ")'),
          ])
-    ip.IP.system = old_system_cmd
+    ip.system = old_system_cmd
 
 
     call_idx = CallableIndexable()

test/test_prefilter.py

@@ -154,12 +154,24 b' esc_handler_tests = ['
     # XXX Possibly, add test for /,; once those are unhooked from %autocall
     ( 'emacs_mode # PYTHON-MODE', handle_emacs ),
     ( ' ',         handle_normal), 
+
     # Trailing qmark combos.  Odd special cases abound
-    ( '!thing?',   handle_shell_escape), # trailing '?' loses to shell esc
-    ( '!thing ?',  handle_shell_escape),
-    ( '!!thing?',  handle_shell_escape),
+
+    # The key is: we don't want the trailing ? to trigger help if it's a
+    # part of a shell glob (like, e.g. '!ls file.?').  Instead, we want the
+    # shell handler to be called.  Due to subtleties of the input string
+    # parsing, however, we only call the shell handler if the trailing ? is
+    # part of something whitespace-separated from the !cmd.  See examples.
+    ( '!thing?',      handle_help), 
+    ( '!thing arg?',  handle_shell_escape),
+    ( '!!thing?',     handle_help),
+    ( '!!thing arg?', handle_shell_escape),
+
+    # For all other leading esc chars, we always trigger help
     ( '%cmd?',     handle_help),
+    ( '%cmd ?',    handle_help),
     ( '/cmd?',     handle_help),
+    ( '/cmd ?',    handle_help),
     ( ';cmd?',     handle_help),
     ( ',cmd?',     handle_help),
     ]
@@ -216,6 +228,9 b' run_handler_tests(['
     ( '%does_not_exist', handle_magic),
     ( 'cd /',            handle_magic),
     ( 'cd = 2',          handle_normal),
+    ( 'r',               handle_magic),
+    ( 'r thing',         handle_magic),
+    ( 'r"str"',          handle_normal),
     ])
 
 # If next elt starts with anything that could be an assignment, func call,