def pre_map(self, function):
"""
Iterates over layout objects pointed in `self.slice` executing `function` on them.
It passes `function` penultimate layout object and the position where to find last one
"""
if isinstance(self.slice, slice):
for i in range(*self.slice.indices(len(self.layout.fields))):
function(self.layout, i)
elif isinstance(self.slice, list):
# A list of pointers Ex: [[[0, 0], 'div'], [[0, 2, 3], 'field_name']]
for pointer in self.slice:
position = pointer[0]
# If it's pointing first level
if len(position) == 1:
function(self.layout, position[-1])
else:
layout_object = self.layout.fields[position[0]]
for i in position[1:-1]:
layout_object = layout_object.fields[i]
try:
function(layout_object, position[-1])
except IndexError:
# We could avoid this exception, recalculating pointers.
# However this case is most of the time an undesired behavior
raise DynamicError(
"Trying to wrap a field within an already wrapped field, \
recheck your filter or layout")
def wrap_together(self, LayoutClass, *args, **kwargs):
"""
Wraps all layout objects pointed in `self.slice` together under a `LayoutClass`
instance with `args` and `kwargs` passed.
"""
if isinstance(self.slice, slice):
# The start of the slice is replaced
start = self.slice.start if self.slice.start is not None else 0
self.layout.fields[start] = self.wrapped_object(
LayoutClass, self.layout.fields[self.slice], *args, **kwargs
)
# The rest of places of the slice are removed, as they are included in the previous
for i in reversed(range(*self.slice.indices(len(self.layout.fields)))):
if i != start:
del self.layout.fields[i]
elif isinstance(self.slice, list):
raise DynamicError("wrap_together doesn't work with filter, only with [] operator")