Hi all,
I posted the following on the python tutor list 3 days ago ... and
haven't heard a peep from anyone - which is highly unusual on that list.
[Apologies for the slightly longer post due to code
with tests cases included at the end .]
I have created a severely restricted environment within with
users can learn the basics of programming in Python.
[note: eval, exec, chr, input, raw_input are not allowed.]
Within that environment, I want to have the user test the five
valid forms that an import statement can have, by attempting to
import a fake module whose name is useful. Other import
statements are disallowed.
1. import useful
2. from useful import *
3. from useful import valid_function1 [, valid_function2, ...]
4. from useful import valid_function as better_named_function
5. import useful as not_so_useful_after_all
As far as I can tell, the following works, but it looks rather
clunky to me. My *very limited* experience with the
re module may have something to do with this.
Any suggestion would be most welcome.
André
===Here's the code formatted (fingers crossed) to work if cut and
pasted from email =
# test_import.py
import re
isolate_words = re.compile(r'\W+') # used with .split()
# pre-compiled some regular expression with allowable use of import
imp_use = re.compile('^import useful', re.MULTILINE)
imp_use_as = re.compile('^import useful as (\w+)', re.MULTILINE)
from_use_imp_star = re.compile('^from useful import \*', re.MULTILINE)
from_use_imp_names = re.compile(
^from useful import (\w+(,[ ]*\w+)*),
re.MULTILINE)
from_use_imp_as = re.compile(
^from useful import (\w+) as (\w+),
re.MULTILINE)
# In the following, r is used so that \b identifies a word boundary,
# and is not interpreted as backslash by Python.
import_misuse = re.compile(r'\bimport\b', re.MULTILINE)
# use to commenting out the valid import statements after processed.
comment_from = re.compile('^from ', re.MULTILINE)
comment_import = re.compile('^import ', re.MULTILINE)
# Create a fake module which can be imported
right = turn_right():\n+\
turn_left()\n+\
turn_left()\n+\
turn_left()\n\n
around = turn_around():\n+\
turn_left()\n+\
turn_left()\n\n
up_east = climb_up_east():\n+\
turn_left()\n+\
move()\n+\
turn_left()\n+\
turn_left()\n+\
turn_left()\n\n
up_west = climb_up_west():\n+\
turn_left()\n+\
turn_left()\n+\
turn_left()\n+\
move()\n+\
turn_left()\n\n
down_west = climb_down_west():\n+\
turn_left()\n+\
move()\n+\
turn_left()\n+\
turn_left()\n+\
turn_left()\n\n
down_east = climb_down_east():\n+\
turn_left()\n+\
turn_left()\n+\
turn_left()\n+\
move()\n+\
turn_left()\n\n
commands = {'turn_right': right, 'turn_around': around,
'climb_up_east': up_east, 'climb_up_west': up_west,
'climb_down_east': down_east, 'climb_down_west': down_west}
#=== end of info on fake module
# The following fonctions are helper functions to
# process the import statement:
# they add the appropriate imported commands
# before the import statement,
# before commenting out (by pre-pending #) the import statement line
def import_useful():
added_text = ''
for instruction in commands:
new = def + 'useful.' + commands[instruction]
added_text += new
return added_text, True
def from_useful_import_star():
added_text = ''
for instruction in commands:
new = def + commands[instruction]
added_text += new
return added_text, True
def import_useful_as(syn):
added_text = ''
for instruction in commands:
new = def + syn + '.' + commands[instruction]
added_text += new
return added_text, True
def from_useful_import_names(names):
added_text = ''
for instruction in isolate_words.split(names):
try:
new = def + commands[instruction]
except:
print instruction, not found in module useful
added_text += new
return added_text, True
def from_useful_import_as(name, syn):
added_text = ''
try:
new = def + commands[name].replace(name, syn)
except:
print name, not found in module useful
added_text += new
return added_text, True
def process_no_import():
added_text = ''
return added_text, True
# the basic processing function
def process_file(file_text):
if imp_use_as.search(file_text): # look for import useful as ...
syn = imp_use_as.findall(file_text)
