From 53c0c308e3be3ff8da2aec67eccf597a43e5976b 2007-05-26 10:06:26
From: vivainio
Date: 2007-05-26 10:06:26
Subject: [PATCH] Add generics.py, result_display generic, first impl is LSString result printer
---

diff --git a/IPython/Prompts.py b/IPython/Prompts.py
index 1bd3d24..a70ad5b 100644
--- a/IPython/Prompts.py
+++ b/IPython/Prompts.py
@@ -2,7 +2,7 @@
 """
 Classes for handling input/output prompts.
 
-$Id: Prompts.py 2349 2007-05-15 16:20:35Z vivainio $"""
+$Id: Prompts.py 2397 2007-05-26 10:06:26Z vivainio $"""
 
 #*****************************************************************************
 #       Copyright (C) 2001-2006 Fernando Perez <fperez@colorado.edu>
@@ -30,6 +30,7 @@ from IPython.Itpl import ItplNS
 from IPython.ipstruct import Struct
 from IPython.macro import Macro
 from IPython.genutils import *
+from IPython.ipapi import TryNext
 
 #****************************************************************************
 #Color schemes for Prompts.
@@ -536,8 +537,10 @@ class CachedOutput:
         Do ip.set_hook("result_display", my_displayhook) for custom result
         display, e.g. when your own objects need special formatting.
         """
-
-        return self.shell.hooks.result_display(arg)
+        try:
+            return IPython.generics.result_display(arg)
+        except TryNext:            
+            return self.shell.hooks.result_display(arg)
 
     # Assign the default display method:
     display = _display
diff --git a/IPython/generics.py b/IPython/generics.py
new file mode 100644
index 0000000..9944a45
--- /dev/null
+++ b/IPython/generics.py
@@ -0,0 +1,28 @@
+from IPython.ipapi import TryNext
+from IPython.external.simplegeneric import generic
+
+""" 'Generic' functions for extending IPython
+
+See http://cheeseshop.python.org/pypi/simplegeneric
+
+Here's an example from genutils.py:
+
+    def print_lsstring(arg):
+        """ Prettier (non-repr-like) and more informative printer for LSString """
+        print "LSString (.p, .n, .l, .s available). Value:"
+        print arg
+        
+    print_lsstring = result_display.when_type(LSString)(print_lsstring)
+
+(Yes, the nasty syntax is for python 2.3 compatibility. Your own extensions
+can use the niftier decorator syntax)
+
+"""
+
+@generic
+def result_display(result):
+    """ print the result of computation """
+    raise TryNext
+
+result_display = generic(result_display)
+
diff --git a/IPython/genutils.py b/IPython/genutils.py
index a9c28a2..6148b72 100644
--- a/IPython/genutils.py
+++ b/IPython/genutils.py
@@ -5,7 +5,7 @@ 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 2371 2007-05-23 18:40:26Z vivainio $"""
+$Id: genutils.py 2397 2007-05-26 10:06:26Z vivainio $"""
 
 #*****************************************************************************
 #       Copyright (C) 2001-2006 Fernando Perez. <fperez@colorado.edu>
@@ -36,6 +36,7 @@ import warnings
 import IPython
 from IPython.Itpl import Itpl,itpl,printpl
 from IPython import DPyGetOpt
+from IPython.generics import result_display
 from path import path
 if os.name == "nt":
     from IPython.winconsole import get_console_size
@@ -872,6 +873,7 @@ class LSString(str):
         .l (or .list) : value as list (split on newlines).
         .n (or .nlstr): original value (the string itself).
         .s (or .spstr): value as whitespace-separated string.
+        .p (or .paths): list of path objects
         
     Any values which require transformations are computed only once and
     cached.
@@ -912,6 +914,14 @@ class LSString(str):
     p = paths = property(get_paths)
 
 
+
+def print_lsstring(arg):
+    """ Prettier (non-repr-like) and more informative printer for LSString """
+    print "LSString (.p, .n, .l, .s available). Value:"
+    print arg
+    
+print_lsstring = result_display.when_type(LSString)(print_lsstring)
+
 #----------------------------------------------------------------------------
 class SList(list):
     """List derivative with a special access attributes.
@@ -921,7 +931,8 @@ class SList(list):
         .l (or .list) : value as list (the list itself).
         .n (or .nlstr): value as a string, joined on newlines.
         .s (or .spstr): value as a string, joined on spaces.
-
+        .p (or .paths): list of path objects
+        
     Any values which require transformations are computed only once and
     cached."""