add script magics

Base %%script magic, and add wrappers for a few common interpreters.

The list of wrapped magics is configurable.

IPython/core/magics/script.py

@@ -0,0 +1,155 b''
+"""Magic functions for running cells in various scripts."""
+#-----------------------------------------------------------------------------
+#  Copyright (c) 2012 The IPython Development Team.
+#
+#  Distributed under the terms of the Modified BSD License.
+#
+#  The full license is in the file COPYING.txt, distributed with this software.
+#-----------------------------------------------------------------------------
+
+#-----------------------------------------------------------------------------
+# Imports
+#-----------------------------------------------------------------------------
+
+# Stdlib
+import os
+import re
+import sys
+from subprocess import Popen, PIPE
+
+# Our own packages
+from IPython.config.configurable import Configurable
+from IPython.core.error import UsageError
+from IPython.core.magic import  (
+    Magics, magics_class, line_magic, cell_magic
+)
+from IPython.testing.skipdoctest import skip_doctest
+from IPython.utils.process import find_cmd, FindCmdError
+from IPython.utils.traitlets import List, Dict
+
+#-----------------------------------------------------------------------------
+# Magic implementation classes
+#-----------------------------------------------------------------------------
+
+@magics_class
+class ScriptMagics(Magics, Configurable):
+    """Magics for talking to scripts
+    
+    This defines a base `%%script` cell magic for running a cell
+    with a program in a subprocess, and registers a few top-level
+    magics that call %%script with common interpreters.
+    """
+    script_magics = List(config=True,
+        help="""Extra script cell magics to define
+        
+        This generates simple wrappers of `%%script foo` as `%%foo`.
+        
+        If you want to add script magics that aren't on your path,
+        specify them in script_paths
+        """,
+    )
+    def _script_magics_default(self):
+        """default to a common list of programs if we find them"""
+        
+        defaults = []
+        to_try = []
+        if os.name == 'nt':
+            defaults.append('cmd')
+            to_try.append('powershell')
+        to_try.extend([
+            'sh',
+            'bash',
+            'perl',
+            'ruby',
+            'python3',
+            'pypy',
+        ])
+        
+        for cmd in to_try:
+            if cmd in self.script_paths:
+                defaults.append(cmd)
+            else:
+                try:
+                    find_cmd(cmd)
+                except FindCmdError:
+                    # command not found, ignore it
+                    pass
+                except ImportError:
+                    # Windows without pywin32, find_cmd doesn't work
+                    pass
+                else:
+                    defaults.append(cmd)
+        return defaults
+    
+    script_paths = Dict(config=True,
+        help="""Dict mapping short 'ruby' names to full paths, such as '/opt/secret/bin/ruby'
+        
+        Only necessary for items in script_magics where the default path will not
+        find the right interpreter.
+        """
+    )
+    
+    def __init__(self, shell=None):
+        Configurable.__init__(self, config=shell.config)
+        self._generate_script_magics()
+        Magics.__init__(self, shell=shell)
+    
+    def _generate_script_magics(self):
+        cell_magics = self.magics['cell']
+        for name in self.script_magics:
+            cell_magics[name] = self._make_script_magic(name)
+    
+    def _make_script_magic(self, name):
+        """make a named magic, that calls %%script with a particular program"""
+        # expand to explicit path if necessary:
+        script = self.script_paths.get(name, name)
+        
+        def named_script_magic(line, cell):
+            # if line, add it as cl-flags
+            if line:
+                 line = "%s %s" % (script, line)
+            else:
+                line = script
+            return self.shebang(line, cell)
+        
+        # write a basic docstring:
+        named_script_magic.__doc__ = \
+        """%%{name} script magic
+        
+        Run cells with {script} in a subprocess.
+        
+        This is a shortcut for `%%script {script}`
+        """.format(**locals())
+        
+        return named_script_magic
+
+    @cell_magic("script")
+    def shebang(self, line, cell):
+        """Run a cell via a shell command
+        
+        The `%%script` line is like the #! line of script,
+        specifying a program (bash, perl, ruby, etc.) with which to run.
+        
+        The rest of the cell is run by that program.
+        
+        Examples
+        --------
+        ::
+        
+            In [1]: %%script bash
+               ...: for i in 1 2 3; do
+               ...:   echo $i
+               ...: done
+            1
+            2
+            3
+        """
+        p = Popen(line, stdout=PIPE, stderr=PIPE, stdin=PIPE)
+        out,err = p.communicate(cell)
+        sys.stdout.write(out)
+        sys.stdout.flush()
+        sys.stderr.write(err)
+        sys.stderr.flush()
+    
+    # expose %%script as %%!
+    cell_magic('!')(shebang)

IPython/core/interactiveshell.py

@@ -2017,7 +2017,8 b' class InteractiveShell(SingletonConfigurable):'
         self.register_magics(m.AutoMagics, m.BasicMagics, m.CodeMagics,
             m.ConfigMagics, m.DeprecatedMagics, m.ExecutionMagics,
             m.ExtensionMagics, m.HistoryMagics, m.LoggingMagics,
-            m.NamespaceMagics, m.OSMagics, m.PylabMagics )
+            m.NamespaceMagics, m.OSMagics, m.PylabMagics, m.ScriptMagics,
+        )
 
         # FIXME: Move the color initialization to the DisplayHook, which
         # should be split into a prompt manager and displayhook. We probably

IPython/core/magics/__init__.py

@@ -25,6 +25,7 b' from .logging import LoggingMagics'
 from .namespace import NamespaceMagics
 from .osm import OSMagics
 from .pylab import PylabMagics
+from .script import ScriptMagics
 
 #-----------------------------------------------------------------------------
 # Magic implementation classes