import traceback
import optparse
import inspect
import sys
import os
import shlex
from ast import literal_eval as safe_eval
try:
_maxsize = sys.maxint
except:
# python3
_maxsize = sys.maxsize
PY3 = sys.version_info[0] == 3
class MagicOptionParser(optparse.OptionParser):
def error(self, msg):
raise Exception('Magic Parse error: "%s"' % msg)
def exit(self, status=0, msg=None):
if msg:
sys.stderr.write(msg)
raise Exception(msg)
## FIXME: override help to also stop processing
## currently --help gives syntax error
[docs]class Magic(object):
"""
Base class to define magics for MetaKernel based kernels.
Users can redefine the default magics provided by Metakernel
by creating a module with the exact same name as the
Metakernel magic.
For example, you can override %matplotlib in your kernel by
writing a new magic inside magics/matplotlib_magic.py
"""
def __init__(self, kernel):
self.kernel = kernel
self.evaluate = True
self.code = ''
def get_args(self, mtype, name, code, args) :
self.code = code
old_args = args
mtype = mtype.replace('sticky', 'cell')
func = getattr(self, mtype + '_' + name)
try:
args, kwargs = _parse_args(func, args, usage=self.get_help(mtype, name))
except Exception as e:
self.kernel.Error(str(e))
return self
arg_spec = inspect.getfullargspec(func) if PY3 \
else inspect.getargspec(func)
fargs = arg_spec.args
if fargs[0] == 'self':
fargs = fargs[1:]
fargs = [f for f in fargs if not f in kwargs.keys()]
if len(args) > len(fargs) and not arg_spec.varargs:
extra = ' '.join(str(s) for s in (args[len(fargs) - 1:]))
args = args[:len(fargs) - 1] + [extra]
return (args, kwargs, old_args)
def call_magic(self, mtype, name, code, args):
self.code = code
old_args = args
mtype = mtype.replace('sticky', 'cell')
func = getattr(self, mtype + '_' + name)
try:
args, kwargs = _parse_args(func, args, usage=self.get_help(mtype, name))
except Exception as e:
self.kernel.Error(str(e))
return self
arg_spec = inspect.getfullargspec(func) if PY3 \
else inspect.getargspec(func)
fargs = arg_spec.args
if fargs[0] == 'self':
fargs = fargs[1:]
fargs = [f for f in fargs if not f in kwargs.keys()]
if len(args) > len(fargs) and not arg_spec.varargs:
extra = ' '.join(str(s) for s in (args[len(fargs) - 1:]))
args = args[:len(fargs) - 1] + [extra]
try:
try:
func(*args, **kwargs)
except TypeError:
func(old_args)
except Exception as exc:
msg = "Error in calling magic '%s' on %s:\n %s\n args: %s\n kwargs: %s" % (
name, mtype, str(exc), args, kwargs)
self.kernel.Error(msg)
self.kernel.Error(traceback.format_exc())
self.kernel.Error(self.get_help(mtype, name))
# return dummy magic to end processing:
return Magic(self.kernel)
return self
def get_help(self, mtype, name, level=0):
if hasattr(self, mtype + '_' + name):
func = getattr(self, mtype + '_' + name)
if level == 0:
if func.__doc__:
return _trim(func.__doc__)
else:
return "No help available for magic '%s' for %ss." % (name, mtype)
else:
filename = inspect.getfile(func)
if filename and os.path.exists(filename):
with open(filename) as f: return f.read()
else:
return "No help available for magic '%s' for %ss." % (name, mtype)
else:
return "No such magic '%s' for %ss." % (name, mtype)
def get_help_on(self, info, level=0):
return "Sorry, no help is available on '%s'." % info['code']
[docs] def get_completions(self, info):
"""
Get completions based on info dict from magic.
"""
return []
def get_magics(self, mtype):
magics = []
for name in dir(self):
if name.startswith(mtype + '_'):
magics.append(name.replace(mtype + '_', ''))
return magics
def get_code(self):
return self.code
def post_process(self, retval):
return retval
[docs]def option(*args, **kwargs):
"""Return decorator that adds a magic option to a function.
"""
def decorator(func):
help_text = ""
if not getattr(func, 'has_options', False):
func.has_options = True
func.options = []
help_text += 'Options:\n-------\n'
try:
option = optparse.Option(*args, **kwargs)
except optparse.OptionError:
help_text += args[0] + "\n"
else:
help_text += _format_option(option) + "\n"
func.options.append(option)
if func.__doc__:
func.__doc__ += _indent(func.__doc__, help_text)
else:
func.__doc__ = help_text
return func
return decorator
def _parse_args(func, args, usage=None):
"""Parse the arguments given to a magic function"""
if isinstance(args, list):
args = ' '.join(args)
args = _split_args(args)
kwargs = dict()
if getattr(func, 'has_options', False):
parser = MagicOptionParser(usage=usage, conflict_handler="resolve")
parser.add_options(func.options)
left = []
value = None
if '--' in args:
left = args[:args.index('--')]
value, args = parser.parse_args(args[args.index('--') + 1:])
else:
while args:
try:
value, args = parser.parse_args(args)
except Exception:
left.append(args.pop(0))
else:
break
args = left + args
if value:
kwargs = value.__dict__
new_args = []
for arg in args:
try:
new_args.append(safe_eval(arg))
except:
new_args.append(arg)
for (key, value) in kwargs.items():
try:
kwargs[key] = safe_eval(value)
except:
pass
return new_args, kwargs
def _split_args(args):
try:
# do not use posix mode, to avoid eating quote characters
args = shlex.split(args, posix=False)
except:
# parse error; let's pass args along rather than crashing
args = args.split()
new_args = []
temp = ''
for arg in args:
if arg.startswith('-'):
new_args.append(arg)
elif temp:
arg = temp + ' ' + arg
try:
safe_eval(arg)
except:
temp = arg
else:
new_args.append(arg)
temp = ''
elif arg.startswith(('(', '[', '{')) or '(' in arg:
try:
safe_eval(arg)
except:
temp = arg
else:
new_args.append(arg)
else:
new_args.append(arg)
if temp:
new_args.append(temp)
return new_args
def _format_option(option):
output = ''
if option._short_opts:
output = option._short_opts[0] + ' '
output += option.get_opt_string() + ' '
output += ' ' * (15 - len(output))
output += option.help + ' '
if not option.default == ('NO', 'DEFAULT'):
output += '[default: %s]' % option.default
return output
def _trim(docstring, return_lines=False):
"""
Trim of unnecessary leading indentations.
"""
# from: http://legacy.python.org/dev/peps/pep-0257/
if not docstring:
return ''
# Convert tabs to spaces (following the normal Python rules)
# and split into a list of lines:
lines = docstring.expandtabs().splitlines()
indent = _min_indent(lines)
# Remove indentation (first line is special):
trimmed = [lines[0].strip()]
if indent < _maxsize:
for line in lines[1:]:
trimmed.append(line[indent:].rstrip())
# Strip off trailing and leading blank lines:
while trimmed and not trimmed[-1]:
trimmed.pop()
while trimmed and not trimmed[0]:
trimmed.pop(0)
if return_lines:
return trimmed
else:
# Return a single string:
return '\n'.join(trimmed)
def _min_indent(lines):
"""
Determine minimum indentation (first line doesn't count):
"""
indent = _maxsize
for line in lines[1:]:
stripped = line.lstrip()
if stripped:
indent = min(indent, len(line) - len(stripped))
return indent
def _indent(docstring, text):
"""
Returns text indented at appropriate indententation level.
"""
if not docstring:
return text
lines = docstring.expandtabs().splitlines()
indent = _min_indent(lines)
if indent < _maxsize:
newlines = _trim(text, return_lines=True)
return "\n" + ("\n".join([(" " * indent) + line for line in newlines]))
else:
return "\n" + text