def input_object(prompt_text, cast, default=None, castarg=[], castkwarg={}):
"""Gets input from the command line and validates it.
prompt_text
A string. Used to prompt the user.
cast
This can be any callable object (class, function, type, etc). It
simply calls the cast with the given arguements and returns the
result. If a ValueError is raised, it
will output an error message and prompt the user again.
Because some builtin python objects don't do casting in the way
that we might like you can easily write a wrapper function that
looks and the input and returns the appropriate object or exception.
Look in the cast submodule for examples.
default
function returns this value if the user types nothing in. This is
can be used to cancel the input so-to-speek
castarg, castkwarg
list and dictionary. Extra arguments passed on to the cast.
"""
while True:
try:
t = raw_input(prompt_text)
if t == '': return default
value = cast(t, *castarg, **castkwarg)
except ValueError, details:
if cast in NICE_INPUT_ERRORS: # see comment above this constant
stdout.write(ERROR_MESSAGE % (NICE_INPUT_ERRORS[cast] % t))
else: stdout.write(ERROR_MESSAGE % (DEFAULT_INPUT_ERRORS % str(details)))
continue
except EOFError:
return false
def file_chooser(prompt_text = "Enter File: ", default=None, filearg=[], filekwarg={}):
"""A simple tool to get a file from the user. Takes keyworded arguemnts
and passes them to open().
If the user enters nothing the function will return the ``default`` value.
Otherwise it continues to prompt the user until it get's a decent response.
filekwarg may contain arguements passed on to ``open()``.
"""
try:
import readline
import rl
completer = rl.PathCompleter()
readline.set_completer_delims(completer.delims)
readline.parse_and_bind("tab: complete")
readline.set_completer(completer.complete)
except ImportError:
pass
while True:
f = raw_input(prompt_text)
if f == '': return default
f = os.path.expanduser(f)
if len(f) != 0 and f[0] == os.path.sep:
f = os.path.abspath(f)
try:
return open(f, *filearg, **filekwarg)
except IOError, e:
stdout.write(ERROR_MESSAGE % ("unable to open %s : %s" % (f, e)))
def query(prompt_text, answers, default=None, list_values = False, ignorecase = True ):
"""Preset a few options
The prompt_text argument is a string, nothing magical.
The answers argument accepts input in two different forms. The simpler form
(a tuple with strings) looks like:
.. code-block:: Python
('Male','Female')
And it will pop up a question asking the user for a gender and requiring
the user to enter either 'male' or 'female' (case doesn't matter unless
you set the third arguement to false).
The other form is something like:
.. code-block:: Python
({'values':('Male','M'),'fg':'cyan'},
{'values':('Female','F'),'fg':'magenta'})
This will pop up a question with Male/Female (each with appropriate
colouring). Additionally, if the user types in just 'M', it will be
treated as if 'Male' was typed in. The first item in the 'values' tuple
is treated as default and is the one that is returned by the function
if the user chooses one in that group.
In addition the function can handle non-string objects quite fine. It
simple displays the output object.__str__() and compares the user's input
against that. So the the code
.. code-block:: Python
query("Python rocks? ",(True, False))
will return a bool (True) when the user types in the string 'True' (Of
course there isn't any other reasonable answer than True anyways :P)
``default`` is the value function returns if the user types nothing in. This is
can be used to cancel the input so-to-speek
Using list_values = False will display a list, with descriptions printed out
from the 'desc' keyword
"""
answers = list(answers)
for i in range(len(answers)):
if not isinstance(answers[i], dict):
answers[i] = {'values': [answers[i]]}
try:
import readline
import rl
wordlist = [ str(values) for answer in answers
for values in answer['values']]
completer = rl.ListCompleter(wordlist, ignorecase)
readline.parse_and_bind("tab: complete")
readline.set_completer(completer.complete)
except ImportError:
pass
answerslist = []
if list_values:
for item in answers:
answerslist.append(
color('bright', fg=item.get('fg'), bg=item.get('bg')) +
str(item['values'][0]) +
color('default') +
' : ' + item['desc'])
prompt_text += os.linesep + os.linesep.join(answerslist) + os.linesep
else:
for item in answers:
answerslist.append(
color('bright', fg=item.get('fg'), bg=item.get('bg')) +
str(item['values'][0]) +
color('default'))
prompt_text += '[' + '/'.join(answerslist) + ']'
while True:
stdout.write(prompt_text)
t = raw_input(': ')
if t == '': return default
if ignorecase: response = t.lower()
else: response = t
for item in answers:
for a in item['values']:
if ignorecase and (response == str(a).lower()):
return item['values'][0]
if response == a:
return item['values'][0]
stdout.write(ERROR_MESSAGE % (
"Response '%s' not understood, please try again." % t))
