def build_named_args_command(self):
com = Command('named my_arg <-f filename> [-g othername]', 'Demonstrate arguments')
def _val(*args, **kwargs):
success,message = com.default_validate(*args, **kwargs)
if not success:
if len(args) == 0 and len(kwargs) == 0:
self.put("""
Some commands accept command line arguments.
When creating a command, you specify these arguments with a special (simple) syntax.
For example, this command is called "%s". It accepts both positional and named arguments.
Positional arguments are indicated by a bare word following the command's name
in the command definition.
Named arguments are wrapped in either <> or [], and contain both the argument name
(starting with '-') and a helpful tip about the argument function.
Named arguments with <> are required, those with [] are optional.
This command also demonstrates customizable tab completion hooks. Try pressing
Tab after typing '%s s' and before typing enter. You'll see a list of possible
completions for your argument.
You can customize these commands by supplying callbacks to Command.tabcomplete_hooks.
Try passing arguments to this command!
""" % (com.name, com.name))
else:
self.put("""
This command requires one unnamed argument followed by a named argument (-f).
Try this:
%s helloworld -f data.txt
""" % com.name)
return (False, message)
return (success, message)
com.validate = _val
def _run(*args, **kwargs):
self.put("Got arguments:")
self.put(args)
self.put(kwargs)
self.put("Arguments are passed around in a format quite familiar to python:")
self.put("Positional arguments in a list, named arguments in a dictionary")
return constants.CHOICE_VALID
com.run = _run
def _complete_myarg(frag):
return ['some', 'random', 'choices']
com.tabcomplete_hooks['my_arg'] = _complete_myarg
def _complete_file(frag):
from os import listdir
from os.path import isfile, join
onlyfiles = [f for f in listdir('.') if isfile(join('.',f))]
return onlyfiles
com.tabcomplete_hooks['filename'] = _complete_file
return com
def build_sticker_command(self):
com = Command('make_sticker text', 'Make a new sticker')
def _run(*args, **kwargs):
self.put("""
This command places a 'sticker' on the terminal. Use these to present persistent
data to the user.
""")
self.sticker(" ".join(args))
return constants.CHOICE_VALID
com.run = _run
return com
def build_hello_command(self):
com = Command('first_command', 'Intro to commands')
def _run(*args, **kwargs):
self.put("""
Congratulations, you just invoked your first command in Candela.
This text is being printed from inside a callback function passed to the library
via a Command object.
You can print text to your shell from anywhere in your Shell subclass by calling
self.put().
""")
return constants.CHOICE_VALID
com.run = _run
return com
def build_builtin_command(self):
com = Command('builtins', 'Go to builtin commands menu')
def _run(*args, **kwargs):
self.put("""
Commands can conditionally lead the user to other menus.
This demo app has two menus defined: the main menu and the built-in commands menu.
The command you just ran has returned the string 'builtins' to point to the
builtins menu. 'builtins' is the name of the new menu.
Notice that the options menu has changed to reflect the new commands available in this menu.
""")
return 'builtins'
com.run = _run
return com
def build_complex_command(self):
com = Command('cat <-f filename>', 'Demonstrate arbitrary python running')
def _run(*args, **kwargs):
self.put("""
Commands can run arbitrary python via a callback. Here's a callback that reads a
file from your local drive and prints it to the shell.
""")
try:
with open(kwargs['f'], 'r') as f:
self.put(f.read())
except IOError:
self.put("%s : No such file!" % kwargs['f'])
return constants.CHOICE_VALID
com.run = _run
return com
def build_invalid_command(self):
com = Command('broken', 'Demonstrate invalid command')
def _run(*args, **kwargs):
self.put("I will never print")
return constants.CHOICE_VALID
com.run = _run
def _val(*args, **kwargs):
message = """
You can write custom validation functions for your commands.
A validation function will run before execution of the command.
If the validation returns False, the command is not run.
The default validation function checks for the presence of all required
arguments, but you can override this behavior by setting the Command's validate member.
This is a command that always fails to validate.
"""
return (False, message)
com.validate = _val
return com
