New demo class, very handy for interactive presentations.

IPython/demo.py

@@ -0,0 +1,115 b''
+"""Module for interactive demos using IPython.
+"""
+#*****************************************************************************
+#       Copyright (C) 2005 Fernando Perez. <[e-mail]>
+#
+#  Distributed under the terms of the BSD License.  The full license is in
+#  the file COPYING, distributed as part of this software.
+#
+#*****************************************************************************
+
+import exceptions
+
+from IPython.PyColorize import Parser
+from IPython.genutils import marquee
+
+class DemoError(exceptions.Exception): pass
+
+class Demo:
+    def __init__(self,fname,pause_mark='# pause',auto=False):
+
+        self.fname = fname
+        self.pause_mark = pause_mark
+        self.auto = auto
+
+        # get a few things from ipython.  While it's a bit ugly design-wise,
+        # it ensures that things like color scheme and the like are always in
+        # sync with the ipython mode being used.  This class is only meant to
+        # be used inside ipython anyways,  so it's OK.
+        self.ip_showtraceback = __IPYTHON__.showtraceback
+        self.ip_ns = __IPYTHON__.user_ns
+        self.ip_colors = __IPYTHON__.rc['colors']
+
+        # read data and parse into blocks
+        fobj = file(fname,'r')
+        self.src = fobj.read()
+        fobj.close()
+        self.src_blocks = [b.strip() for b in self.src.split(pause_mark) if b]
+        self.nblocks = len(self.src_blocks)
+
+        # try to colorize blocks
+        colorize = Parser().format
+        col_scheme = self.ip_colors
+        self.src_blocks_colored = [colorize(s_blk,'str',col_scheme)
+                                   for s_blk in self.src_blocks]
+
+        # finish initialization
+        self.reset()
+
+    def reset(self):
+        self.user_ns  = {}
+        self.finished = False
+        self.block_index = 0
+
+    def again(self):
+        self.block_index -= 1
+        self()
+
+
+    def _validate_index(self,index):
+        if index<0 or index>=self.nblocks:
+            raise ValueError('invalid block index %s' % index)
+
+    def seek(self,index):
+        self._validate_index(index)
+        self.block_index = index-1
+        self.finished = False
+
+    def show(self,index=None):
+        if index is None:
+            index = self.block_index
+        else:
+            self._validate_index(index)
+        print marquee('<%s> block # %s (%s/%s)' %
+                      (self.fname,index,index+1,self.nblocks))
+        print self.src_blocks_colored[index],
+        
+    def __call__(self,index=None):
+        """run a block of the demo.
+
+        If index is given, it should be an integer >=1 and <= nblocks.  This
+        means that the calling convention is one off from typical Python
+        lists.  The reason for the inconsistency is that the demo always
+        prints 'Block n/N, and N is the total, so it would be very odd to use
+        zero-indexing here."""
+
+        if index is None and self.finished:
+            print 'Demo finished.  Use reset() if you want to rerun it.'
+            return
+        if index is None:
+            index = self.block_index
+        self._validate_index(index)
+        try:
+            next_block = self.src_blocks[index]
+            self.block_index += 1
+            self.show(index)
+            if not self.auto:
+                print marquee('Press <q> to quit, <Enter> to execute...'),
+                ans = raw_input().strip()
+                if ans:
+                    print marquee('Block NOT executed')
+                    return
+            
+            exec next_block in self.user_ns
+            
+        except:
+            self.ip_showtraceback(filename=self.fname)
+        else:
+            self.ip_ns.update(self.user_ns)
+
+        if self.block_index == self.nblocks:
+            print
+            print marquee(' END OF DEMO ')
+            print marquee('Use reset() if you want to rerun it.')
+            self.finished = True
+

IPython/genutils.py

@@ -5,7 +5,7 b' General purpose utilities.'
 This is a grab-bag of stuff I find useful in most programs I write. Some of
 these things are also convenient when working at the command line.
 
-$Id: genutils.py 874 2005-09-20 20:13:04Z fperez $"""
+$Id: genutils.py 894 2005-09-22 07:16:18Z fperez $"""
 
 #*****************************************************************************
 #       Copyright (C) 2001-2004 Fernando Perez. <[e-mail]>
@@ -899,6 +899,16 b' def ask_yes_no(prompt,default=None):'
     return answers[ans]
 
 #----------------------------------------------------------------------------
+def marquee(txt='',width=80,mark='*'):
+    """Return the input string centered in a 'marquee'."""
+    if not txt:
+        return (mark*width)[:width]
+    nmark = (width-len(txt)-2)/len(mark)/2
+    if nmark < 0: nmark =0
+    marks = mark*nmark
+    return '%s %s %s' % (marks,txt,marks)
+
+#----------------------------------------------------------------------------
 class EvalDict:
     """
     Emulate a dict which evaluates its contents in the caller's frame.

IPython/iplib.py

@@ -6,7 +6,7 b' Requires Python 2.1 or newer.'
 
 This file contains all the classes and helper functions specific to IPython.
 
-$Id: iplib.py 874 2005-09-20 20:13:04Z fperez $
+$Id: iplib.py 894 2005-09-22 07:16:18Z fperez $
 """
 
 #*****************************************************************************
@@ -1272,7 +1272,7 b' want to merge them back into the new files.""" % locals()'
             return
         pdb.pm()
 
-    def showtraceback(self,exc_tuple = None):
+    def showtraceback(self,exc_tuple = None,filename=None):
         """Display the exception that just occurred."""
 
         # Though this won't be called by syntax errors in the input line,
@@ -1282,7 +1282,7 b' want to merge them back into the new files.""" % locals()'
         else:
             type, value, tb = exc_tuple
         if type is SyntaxError:
-            self.showsyntaxerror()
+            self.showsyntaxerror(filename)
         else:
             sys.last_type = type
             sys.last_value = value

doc/ChangeLog

@@ -1,9 +1,20 b''
[phone]  Fernando Perez  <[e-mail]>
+
+	* IPython/genutils.py (marquee): little utility used by the demo
+	code, handy in general.
+
+	* IPython/demo.py (Demo.__init__): new class for interactive
+	demos.  Not documented yet, I just wrote it in a hurry for
+	scipy'05.  Will docstring later.
+
 2005-09-20  Fernando Perez  <[e-mail]>
 
 	* IPython/Shell.py (sigint_handler): Drastic simplification which
 	also seems to make Ctrl-C work correctly across threads!  This is
 	so simple, that I can't beleive I'd missed it before.  Needs more
 	testing, though.
+	(KBINT): Never mind, revert changes.  I'm sure I'd tried something
+	like this before...
 
 	* IPython/genutils.py (get_home_dir): add protection against
 	non-dirs in win32 registry.