On 2019-10-18 10:23, Ricky Teachey wrote:
but i'm -0 because i am very concerned it will not be obvious to new learners,
without constantly looking it up, whether adding two mappings together would either:
The big trade off I'm gathering from this mega-thread is that the |, |=
operators are more accurate, but less obvious to newcomers, who will first try
+, += instead.
I've tried them in this order myself several times over the years.
Had an idea, why not choose the more accurate syntax: |, |= after all? Then, to
help newcomers and forgetful pros a custom error message is implemented for +,
+=. In pseudo C/Python, something like this:
class dict:
def __add__(self, other):
if isinstance(other, dict):
raise TypeError(
'unsupported operand type(s) for +: … '
'Dictionary merging leads to last-value-wins data '
'loss. If acceptable, use the union "|" operator.'
)
else:
raise TypeError(std_err_msg)
I think it is worth it to lead the newcomer to a moment's reflection on why
dictionary combining/merging is potentially lossy. Everyone is informed with
the proper mental model, then on their way and left alone afterward.
Thoughts?
-Mike
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