From a736ad78adfbbc273299cdbe8d31727baf66a1b7 2013-07-31 01:40:26
From: Alex Rudy <alex.rudy@gmail.com>
Date: 2013-07-31 01:40:26
Subject: [PATCH] Adds p.break_ for explicit newlines in lib.pretty

p.break_() explicitly includes a newline while pretty printing, and maintains indentation.
A simple test is included to show this working.

---

diff --git a/IPython/lib/pretty.py b/IPython/lib/pretty.py
index 36d7824..ee5e059 100644
--- a/IPython/lib/pretty.py
+++ b/IPython/lib/pretty.py
@@ -229,7 +229,17 @@ class PrettyPrinter(_PrettyPrinterBase):
             self.buffer.append(Breakable(sep, width, self))
             self.buffer_width += width
             self._break_outer_groups()
-
+            
+    def break_(self):
+        """
+        Explicitly insert a newline into the output, maintaining correct indentation.
+        """
+        self.flush()
+        self.output.write(self.newline)
+        self.output.write(' ' * self.indentation)
+        self.output_width = self.indentation
+        self.buffer_width = 0
+        
 
     def begin_group(self, indent=0, open=''):
         """
diff --git a/IPython/lib/tests/test_pretty.py b/IPython/lib/tests/test_pretty.py
index 689ae48..db5224c 100644
--- a/IPython/lib/tests/test_pretty.py
+++ b/IPython/lib/tests/test_pretty.py
@@ -58,6 +58,13 @@ class NoModule(object):
 
 NoModule.__module__ = None
 
+class Breaking(object):
+    def _repr_pretty_(self, p, cycle):
+        with p.group(4,"TG: ",":"):
+            p.text("Breaking(")
+            p.break_()
+            p.text(")")
+
 
 def test_indentation():
     """Test correct indentation in groups"""
@@ -118,3 +125,11 @@ def test_pprint_nomod():
     """
     output = pretty.pretty(NoModule)
     nt.assert_equal(output, 'NoModule')
+    
+def test_pprint_break():
+    """
+    Test that p.break_ produces expected output
+    """
+    output = pretty.pretty(Breaking())
+    expected = "TG: Breaking(\n    ):"
+    nt.assert_equal(output, expected)