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* Parameters value lookup: use try..except EAFP rather LBYL approach.

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* Add simple checks for _p, _opts_ default arguments in case they are not
  indexable/dict-like objects. This is needed to avoid bizzare error messages
  later then the Parameters object is in use.
This commit is contained in:
wirawan
2011-09-07 15:05:54 +00:00
parent 1181a7e516
commit 4aff740f55
1 changed files with 47 additions and 9 deletions
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56
params/params_flat.py
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@@ -1,4 +1,4 @@
# $Id: params_flat.py,v 1.2 2011-03-10 19:20:35 wirawan Exp $
# $Id: params_flat.py,v 1.3 2011-09-07 15:05:54 wirawan Exp $
#
# wpylib.params.params_flat module
# Created: 20100930
@@ -175,10 +175,17 @@ class Parameters(dict):
"""
if self._no_null_:
for ov in self._list_:
if key in ov and ov[key] != None: return ov[key]
try:
v = ov[key]
if v != None: return v
except KeyError:
pass
else:
for ov in self._list_:
if key in ov: return ov[key]
try:
return ov[key]
except KeyError:
pass
# Otherwise: -- but most likely this will return attribute error:
return dict.__getattribute__(self, key)
def __setattr__(self, key, value):
@@ -196,10 +203,17 @@ class Parameters(dict):
def __getitem__(self, key):
if self._no_null_:
for ov in self._list_:
if key in ov and ov[key] != None: return ov[key]
try:
v = ov[key]
if v != None: return v
except KeyError:
pass
else:
for ov in self._list_:
if key in ov: return ov[key]
try:
return ov[key]
except KeyError:
pass
raise KeyError, "Cannot find parameter `%s'" % key
#def __setitem__(self, key, value): # -- inherited from dict
# self._prm_[key] = value
@@ -274,17 +288,41 @@ class Parameters(dict):
# then _opts_ excess-keyword parameters (see example of doit() above)
if kwparam in localvars:
_opts_ = localvars[kwparam]
contexts.append(_opts_)
if _opts_ != None:
# add this minimal check for a dict-like behavior rather
# than encountering a strange error later
if not hasattr(_opts_, "__getitem__") or not hasattr(_opts_, "__contains__"):
raise TypeError, \
("The keyword parameter (variable/parameter `%s' in function `%s')" +
" is not a dict-like object)") \
% (kwparam, caller.f_code.co_name)
contexts.append(_opts_)
else:
_opts_ = {}
# then opts, an explicitly-defined argument which contain a set of parameters
if userparam in localvars:
opts = localvars[userparam]
contexts.append(opts)
if opts != None:
# add this minimal check for a dict-like behavior rather
# than encountering a strange error later
if not hasattr(opts, "__getitem__") or not hasattr(opts, "__contains__"):
raise TypeError, \
("The user parameter (variable/parameter `%s' in function `%s')" +
" is not a dict-like object)") \
% (userparam, caller.f_code.co_name)
contexts.append(opts)
else:
opts = {}
if userparam in _opts_:
contexts.append(_opts_[userparam])
opts = _opts_[userparam]
if opts != None:
# add this minimal check for a dict-like behavior rather
# than encountering a strange error later
if not hasattr(opts, "__getitem__") or not hasattr(opts, "__contains__"):
raise TypeError, \
("The user parameter (variable/parameter `%s' in function `%s')" +
" is not a dict-like object)") \
% (userparam, caller.f_code.co_name)
contexts.append(opts)
# then this own Parameters data will come here:
contexts.append(self)