Made registering commands better

Registering commands requires adding the name as a string so that we can
have nice PEP 8-compatible class names for commands.

psh/__init__.py

@@ -0,0 +1,11 @@
+from psh.commands import registered_cmds
+
+# Import the exported commands
+from psh.example_cmd import *
+
+# Instantiate the registered commands
+for name, cls in registered_cmds.items():
+	globals()[name] = cls()
+
+# Only export the names of registered commands
+__all__ = registered_cmds.keys()

psh/commands.py

@@ -38,9 +38,11 @@ class BaseCommand(object):
         return cmd
 
 
-registered_cmds = []
+registered_cmds = {}
 
-def register_cmd(cls):
-    """Decorator for putting all of the commands in one nice place."""
-    registered_cmds.append(cls.__name__)
-    return cls
+def register_cmd(name):
+    def decorator(cls):
+        """Decorator for putting all of the commands in one nice place."""
+        registered_cmds[name] = cls
+        return cls
+    return decorator

psh/example_cmd.py

@@ -1,8 +1,8 @@
 from psh.commands import BaseCommand, register_cmd
 
 
-@register_cmd
-class example_cmd(BaseCommand):
+@register_cmd("example")
+class Example(BaseCommand):
     """Simple command that just returns 'example' and 'command'. Does
     nothing at all with the input."""
 
@@ -13,13 +13,13 @@ class example_cmd(BaseCommand):
         return output_generator
 
 
-@register_cmd
-class echo(BaseCommand):
+@register_cmd("echo")
+class Echo(BaseCommand):
     """Echoes anything from the command line arguments as well as input
     from the previous command."""
 
-    def __init__(self, args):
-        super(echo, self).__init__()
+    def __init__(self, args=[]):
+        super(Echo, self).__init__()
         self.args = args
 
     def call(self,*args,**kwargs):