def __init__(self, raw_pattern, raw_previous, weight, alternates,
method, rulename):
""" Create a new Rule object based on information supplied to the
@rule decorator. Arguments:
raw_pattern - simplified regular expression string supplied to @rule
raw_previous - simplified regular expression string supplied to @rule
weight - weight supplied to @rule
alternates - dictionary of variable names and values that can
be substituted in the patterns
method - reference to method decorated by @rule
rulename - modulename.classname.methodname, used to make better
error messages
Raises PatternError, PatternVariableNotFoundError,
PatternVariableValueError
"""
try:
previous = ""
if not raw_pattern:
raise PatternError("Empty string found")
self.pattern = Pattern(raw_pattern, alternates)
previous = "previous "
self.previous = Pattern(raw_previous, alternates)
except (TypeError, PatternError, PatternVariableValueError,
PatternVariableNotFoundError) as e:
msg = " in {0}pattern of {1}".format(previous, rulename)
e.args = (e.args[0] + msg,) + e.args[1:]
raise
self.weight = weight
self.method = method
self.rulename = rulename
def _parse_alternates(self, alternates, script_class_name):
"""Construct Pattern objects for all the values in the alternates
instance variable (hopefully a dictionary) of a Script
subclass, and construct a dictionary of the keys from
alternates and the pattern object. Wrap that in another
dictionary keyed by 'a' so it can be used by %a:varname in
other patterns.
"""
valid = {}
k = ""
try:
for k, v in alternates.items():
valid[k] = Pattern(v, simple=True).formatted_pattern
except Exception as e:
msg = " in alternates"
if k:
msg += '["{0}"]'.format(k)
msg += " of {0}".format(script_class_name)
e.args = (e.args[0] + msg,) + e.args[1:]
raise
return {"a": valid}
