def get_lookup_table(modname, *lookup, **args):
"""
get_lookup_table() is used to get lookup table style sets of variables
from a common facility, allowing the storage in common (global) space
so that multiple scripts can refer to one lookup table
without having to manage where this table is stored. E.g. the Calculator
(see L{Descriptors}) for NIRI data requires a NIRI lookup table that
other parts of the package, unrelated to Descriptors, also need to
access. This facility saves these separate components from knowing
where the configuration is actually stored, or even that other
parts of the system are relying on it, and ensure that changes will
affect every part of the system.
@param modname: namespace specifier for the table... in default case this
is the directory and file name of the module in which the lookup
table is stored, and the file is pure python. However, the Lookups
module can redirect this, using the modname, for example, as a
key to find the lookup table in a database or elsewhere. Nothing like
the latter is done at this time, and what is loaded are pure python
files (e.g. a dict definition) from disk.
@type modname: string
@param lookup: name of the lookup table to load
@type lookup: string
"""
retval = None
context = None
if "context" in args:
context = args["context"]
if context == None:
context = ConfigSpace.get_current_default_context()
# if not context:
# modname = ConfigSpace.lookup_path(modname)
# else:
modname = ConfigSpace.lookup_context_path(modname, context=context)
if not modname or (not os.path.exists(modname)):
return None
if ".py" in modname:
f = file(modname)
g = {}
l = {}
exec(f, g, l)
# print "L38:",l.keys(),l
f.close()
if len(lookup) == 1:
if lookup[0] in l:
retval = l[lookup[0]]
else:
retval = [None]
elif len(lookup) == 0:
retval = []
for key in l:
retval.append(l[key])
else:
retval = []
for item in lookup:
if item in l:
retval.append(l[item])
else:
retval.append(None)
elif ".fits" in modname:
# in this case lookup will have extension ids
table = pyfits.open(modname)
if len(lookup) == 1:
retval = table[lookup[0]]
else:
retval = []
for item in lookup:
retval.append(table[item])
else:
raise "this should never happen, tell someone"
return retval
