I don't have any specific knowledge about this, but it probably has not
been done because it could easily cause some subtle bugs that aren't
immediately obvious, and the benefits aren't that great in comparison to
just using the format specification language to produce % representation.
Consider, if % was a postix operator:
>>> x = 1.11
>>> xmod1 = x % # whoops - forgot second argument, and no error to warn me
>>> print(f"the decimal portion of x is: {xmod1}") # no error here either
the modulo value is: 111.00000000000001%
yuck!
Another problem is: if you want a "%" sign displayed as part of the repr,
this would require a new "percent" numerical subtype with it's own
__repr__. Which opens up a big can of worms:
- should percent instances inter-operate with floats, ints, Decimals....?
- if so, what should the return value be when you add/subtract/etc them
with other types?
Also consider that if this was done, it would be the only postfix operator
in the entire language.
If you really want to do this, you could subclass float and overload the
__rmod__ and just have it take an ellipses as the RHS argument, which
doesn't look too awful to me:
>>> xpct = 1.11 % ... # not too bad! and errors are preserved when
misused...
>>> f"{xpct:.0f}"
'111'
>>> f"{xpct:.0f}%"
'111%'
But IMO there's already a much better way to do all of this:
>>> f"{x:.0%}"
'111%'
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