MRAB wrote:
> On 12/09/2012 19:04, Alister wrote:
>> On Wed, 12 Sep 2012 18:56:46 +0200, Jabba Laci wrote:
>>
>>>> For example:
>>>>
>>>> def install_java():
>>>> pass
>>>>
>>>> def install_tomcat():
>>>> pass
>>>
>>> Thanks for the answers. I decided to use numbers in the name of the
>>> functions to facilitate function calls. Now if you have this menu option
>>> for instance:
>>>
>>> (5) install mc
>>>
>>> You can type just "5" as user input and step_5() is called
>>> automatically. If I use descriptive names like install_java() then
>>> selecting a menu point would be more difficult. And I don't want users
>>> to type "java", I want to stick to simple numbers.
>>>
>>> Laszlo
>>
>> No No NO!
>> you cant just pass user input to system calls without validating it first
>> (google sql injection for examples of the damage unsanitised input can
>> cause, it is not just as SQL problem)
>>
>> it is just as easy so select a reasonably named function as a bad one
>>
>> option=raw_input('select your option :')
>>
>> if option =="1": install_java()
>> if option =="2": install_other()
>>
>> alternatively you cold add your functions into a dictionary an call them
>> from that
>>
>> opts={'1':install java,'2':install_other}
>>
>> option=raw_input('select your option :')
>> opts[option]
>>
>> Poorly named functions are a major example of poor programming style.
>>
>> one of the fundamental pillars for python is readability!
>>
> Or you could do this:
>
>
> def install_java():
> "Install Java"
> print "Installing Java"
>
> def install_tomcat():
> "Install Tomcat"
> print "Installing Tomcat"
>
> menu = [install_java, install_tomcat]
>
> for index, func in enumerate(menu, start=1):
> print "{0}) {1}".format(index, func.__doc__)
>
> option = raw_input("Select your option : ")
>
> try:
> opt = int(option)
> except ValueError:
> print "Not a valid option"
> else:
> if 1 <= opt < len(menu):
> menu[opt - 1]()
> else:
> print "Not a valid option"
I'd still argue that a function index is the wrong approach. You can use tab
completion to make entering descriptive names more convenient:
import cmd
class Cmd(cmd.Cmd):
prompt = "Enter a command (? for help): "
def do_EOF(self, args):
return True
def do_quit(self, args):
return True
@classmethod
def install_command(class_, f):
def wrapped(self, arg):
if arg:
print "Discarding argument {!r}".format(arg)
return f()
wrapped.__doc__ = f.__doc__
wrapped.__name__ = f.__name__
class_._add_method("do_" + f.__name__, wrapped)
return f
@classmethod
def _add_method(class_, methodname, method):
if hasattr(class_, methodname):
raise ValueError("Duplicate command {!r}".format(methodname))
setattr(class_, methodname, method)
command = Cmd.install_command
@command
def install_java():
"Install Java"
print "Installing Java"
@command
def install_tomcat():
"Install Tomcat"
print "Installing Tomcat"
if __name__ == "__main__":
Cmd().cmdloop()
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