spell magic: execute named blocks of code

jupyter_kernel/magics/spell_magic.py

@@ -0,0 +1,115 @@
+# Copyright (c) Calico Development Team.
+# Distributed under the terms of the Modified BSD License.
+# http://calicoproject.org/
+
+from jupyter_kernel import Magic, option
+import inspect
+import ast
+import os
+
+class SpellMagic(Magic):
+    spells = {"renumber-cells": """%%javascript
+
+        var cells = IPython.notebook.get_cells();
+        // We only keep the code cells.
+        cells = cells.filter(function(c)
+            {
+                return c instanceof IPython.CodeCell; 
+            })
+        // We set the input prompt of all code cells.
+        for (var i = 0; i < cells.length; i++) {
+            cells[i].set_input_prompt(i + 1);
+        }
+"""}
+
+    def __init__(self, *args, **kwargs):
+        super(SpellMagic, self).__init__(*args, **kwargs)
+        self._load_spells()
+
+    @option(
+        '-d', '--delete', action='store_true', default=False,
+        help='delete a named spell'
+    )
+    @option(
+        '-l', '--list', action='store_true', default=False,
+        help='list spells'
+    )
+    def line_spell(self, name, delete=False, list=False):
+        """
+        %spell [-l] [-d] [INCANTATION] - call a spell to perform it's magic
+
+        This line magic will execute the spell.
+
+        Example:
+            %spell renumber-cells
+        """
+        if list:
+            retval = "Available spells:\n"
+            if name in ["all", "system"]:
+                retval += "    System:\n"
+                for spell in sorted(self.spells.keys()):
+                    retval += "        %s\n" % spell
+            if name in ["all", "learned"]:
+                retval += "    Learned:\n"
+                for spell in sorted(self.learned.keys()):
+                    retval += "        %s\n" % spell
+            self.kernel.Print(retval)
+        elif name in self.spells:
+            if delete:
+                raise Exception("Can't delete system spell")
+            else:
+                self.code = self.code.strip()
+                if self.code: 
+                    self.code += "\n"
+                self.code += self.spells[name]
+        elif name in self.learned:
+            if delete:
+                del self.learned[name]
+                self._save_spells()
+            else:
+                self.code = self.code.strip()
+                if self.code: 
+                    self.code += "\n"
+                self.code += self.learned[name]
+        else:
+            raise Exception("No such spell: '%s'" % name)
+        self.evaluate = True
+
+    def _load_spells(self):
+        self.learned = {}
+        local_magics_dir = self.kernel.get_local_magics_dir()
+        # Search all of the places there could be spells:
+        files = [os.path.join(os.path.dirname(os.path.abspath(__file__)), "spells.json"),
+                 os.path.join(os.path.dirname(os.path.abspath(inspect.getfile(self.__class__))), "spells.json"),
+                 os.path.join(local_magics_dir, "spells.json")]
+        for spell_file in files:
+            try:
+                data = ast.literal_eval(open(spell_file).read()) 
+            except:
+                continue
+            self.learned.update(data)
+
+    def _save_spells(self):
+        local_magics_dir = self.kernel.get_local_magics_dir()
+        filename = os.path.join(local_magics_dir, "spells.json")
+        open(filename, "w").write(str(self.learned))
+
+    def cell_spell(self, name):
+        """
+        %%spell INCANTATION - teach a spell
+
+        This cell magic will teach the spell.
+
+        Example:
+            %%spell COMMAND
+
+            CODE
+        """
+        self.learned[name] = self.code
+        self._save_spells()
+        self.evaluate = False
+
+def register_magics(kernel):
+    kernel.register_magics(SpellMagic)
+
+