Missing division of time periods

[cstjean]

Currently,

julia> Millisecond(10) / Millisecond(1)
10.0

julia> Minute(10) / Millisecond(1)
ERROR: MethodError: no method matching /(::Minute, ::Millisecond)

If division is supported at all, it would be very convenient to be able to divide across compatible units.

[oscardssmith]

The problem is that there is no unique answer here. Consider Year(1)/Day(1) should this be 364 or 365?

[cstjean]

Right, it should only be done for units that can be converted.

julia> convert(Millisecond, Year(1))
ERROR: MethodError: Cannot `convert` an object of type Year to an object of type Millisecond
Closest candidates are:
  convert(::Type{Millisecond}, ::Second) at /Users/osx/buildbot/slave/package_osx64/build/usr/share/julia/stdlib/v0.7/Dates/src/periods.jl:421
  convert(::Type{Millisecond}, ::Minute) at /Users/osx/buildbot/slave/package_osx64/build/usr/share/julia/stdlib/v0.7/Dates/src/periods.jl:421
  convert(::Type{Millisecond}, ::Hour) at /Users/osx/buildbot/slave/package_osx64/build/usr/share/julia/stdlib/v0.7/Dates/src/periods.jl:421
  ...
Stacktrace:
 [1] top-level scope at none:0

julia> convert(Millisecond, Day(1))
86400000 milliseconds

Converting the bigger of the two units to the smaller unit seems like the best way to go about it.

[oscardssmith]

in that case, only second to millisecond should work, as leap seconds allow impression for all larger units

[oscardssmith]

it's unfortunate, but time units really sex sic suck

[cstjean]

in that case, only second to millisecond should work, as leap seconds allow impression for all larger units

I think that Dates is not meant for high-fidelity date manipulation. Its DateTime + Period arithmetic is not even associative 😛

julia> DateTime(2017, 2) + (Day(30) + Month(1))
2017-03-31T00:00:00

julia> (DateTime(2017, 2) + Day(30)) + Month(1)
2017-04-03T00:00:00

In any case, all I'm asking is for / to be the natural extension of convert.

[laborg]

This has been implemented in #43360

julia> Minute(10) / Millisecond(1)
600000.0