def solve_resolve(expr, vars):
"""Use IStructured.resolve to get member (rhs) from the object (lhs).
This operation supports both scalars and repeated values on the LHS -
resolving from a repeated value implies a map-like operation and returns a
new repeated values.
"""
objs, _ = __solve_for_repeated(expr.lhs, vars)
member = solve(expr.rhs, vars).value
try:
results = [
structured.resolve(o, member) for o in repeated.getvalues(objs)
]
except (KeyError, AttributeError):
# Raise a better exception for the non-existent member.
raise errors.EfilterKeyError(root=expr.rhs,
key=member,
query=expr.source)
except (TypeError, ValueError):
# Is this a null object error?
if vars.locals is None:
raise errors.EfilterNoneError(
root=expr,
query=expr.source,
message="Cannot resolve member %r from a null." % member)
else:
raise
except NotImplementedError:
raise errors.EfilterError(
root=expr,
query=expr.source,
message="Cannot resolve members from a non-structured value.")
return Result(repeated.meld(*results), ())
def solve_select(expr, vars):
"""Use IAssociative.select to get key (rhs) from the data (lhs).
This operation supports both scalars and repeated values on the LHS -
selecting from a repeated value implies a map-like operation and returns a
new repeated value.
"""
data = solve(expr.lhs, vars).value
key = solve(expr.rhs, vars).value
try:
results = [associative.select(d, key) for d in repeated.getvalues(data)]
except (KeyError, AttributeError):
# Raise a better exception for accessing a non-existent key.
raise errors.EfilterKeyError(root=expr, key=key, query=expr.source)
except (TypeError, ValueError):
# Raise a better exception for what is probably a null pointer error.
if vars.locals is None:
raise errors.EfilterNoneError(
root=expr, query=expr.source,
message="Cannot select key %r from a null." % key)
else:
raise
except NotImplementedError:
raise errors.EfilterError(
root=expr, query=expr.source,
message="Cannot select keys from a non-associative value.")
return Result(repeated.meld(*results), ())
def solve_var(expr, vars):
"""Returns the value of the var named in the expression."""
try:
return Result(structured.resolve(vars, expr.value), ())
except (KeyError, AttributeError) as e:
# Raise a better exception for accessing a non-existent member.
raise errors.EfilterKeyError(root=expr,
key=expr.value,
message=e,
query=expr.source)
except (TypeError, ValueError) as e:
# Raise a better exception for what is probably a null pointer error.
if vars.locals is None:
raise errors.EfilterNoneError(
root=expr,
query=expr.source,
message="Trying to access member %r of a null." % expr.value)
else:
raise errors.EfilterTypeError(root=expr,
query=expr.source,
message="%r (vars: %r)" % (e, vars))
except NotImplementedError as e:
raise errors.EfilterError(
root=expr,
query=expr.source,
message="Trying to access member %r of an instance of %r." %
(expr.value, type(vars)))