[Python-ideas] adding dictionaries

[Stephen J. Turnbull]

Terry Reedy writes:


 > This assumes the same range set (of addable items) also.  If Python were 
 > to add d1 + d2 and d1 += d2, I think we should use this existing and 
 > most common definition and add values.

IMHO[1] that's way too special for the generic mapping types.  If one
wants such operations, she should define NumericValuedMapping and
StringValuedMapping etc classes for each additive set of values.

 > >  For functions on different domains, I've seen it used to
 > > mean "apply the appropriate function on the disjoint union of the
 > > domains".
 > 
 > According to https://en.wikipedia.org/wiki/Disjoint_union, d_u has at 
 > least two meaning.

Either meaning will do here, with the distinction that the set-
theoretic meaning (which I intended) applies to any two functions,
while the alternate meaning imposes a restriction on the functions
that can be added (and therefore is inappropriate for this discussion
IMHO).

Footnotes: 
[1]  I mean the "H", I'm no authority.