MethodError trying to print a AnchoredInterval{Week(-1)}

[nickrobinson251]

The behaviour for printing a AnchoredInterval{Day(-1)} is:

julia> dt = DateTime(2016, 8, 11, 2)
2016-08-11T02:00:00

julia> AnchoredInterval{Day(-1)}(dt)
AnchoredInterval{Day(-1), DateTime, Open, Closed}(DateTime("2016-08-11T02:00:00"))

julia> print(ans)
(DE 2016-08-11 02:00:00]

And this style of print is available for AnchoredInterval{T(-1)} if T is Day, Month, Year or Millisecond, Second, Minute, Hour

But errors for Week, Quarter (new in Julia v1.6), or Nanosecond, Microsecond

E.g. for AnchoredInterval{Week(-1)}

julia> dt = DateTime(2016, 8, 11, 2)
2016-08-11T02:00:00

julia> AnchoredInterval{Week(-1)}(dt)
AnchoredInterval{Week(-1), DateTime, Open, Closed}(DateTime("2016-08-11T02:00:00"))

julia> print(ans)
ERROR: MethodError: no method matching prefix(::Type{Week})
Closest candidates are:
  prefix(::Period) at /Users/nick/.julia/packages/Intervals/ua9cq/src/description.jl:58
  prefix(::Type{Year}) at /Users/nick/.julia/packages/Intervals/ua9cq/src/description.jl:62
  prefix(::Type{Month}) at /Users/nick/.julia/packages/Intervals/ua9cq/src/description.jl:63
  ...
Stacktrace:
 [1] prefix(p::Week)
   @ Intervals ~/.julia/packages/Intervals/ua9cq/src/description.jl:59
 [2] description(dt::DateTime, p::Week, suffix::String)
   @ Intervals ~/.julia/packages/Intervals/ua9cq/src/description.jl:41
 [3] description(interval::AnchoredInterval{Week(-1), DateTime, Open, Closed}, s::String)
   @ Intervals ~/.julia/packages/Intervals/ua9cq/src/description.jl:4
 [4] description(i::AnchoredInterval{Week(-1), DateTime, Open, Closed})
   @ Intervals ~/.julia/packages/Intervals/ua9cq/src/description.jl:1
 [5] print(io::Base.TTY, interval::AnchoredInterval{Week(-1), DateTime, Open, Closed})
   @ Intervals ~/.julia/packages/Intervals/ua9cq/src/anchoredinterval.jl:256
 [6] print(xs::AnchoredInterval{Week(-1), DateTime, Open, Closed})
   @ Base ./coreio.jl:3

Assuming there's no reason not to support these Periods, i believe this is just a bug in the print defintions.

I think it can be fixed by adding methods to prefix:

Intervals.jl/src/description.jl

Lines 62 to 68 in f873f70

	prefix(::Type{Year}) = "Y"
	prefix(::Type{Month}) = "Mo"
	prefix(::Type{Day}) = "D"
	prefix(::Type{Hour}) = "H"
	prefix(::Type{Minute}) = "M"
	prefix(::Type{Second}) = "S"
	prefix(::Type{Millisecond}) = "ms"

And adding appropriate tests, like

Intervals.jl/test/anchoredinterval.jl

Lines 429 to 437 in f873f70

	AnchoredInterval{Day(-1)}(DateTime(dt)),
	"(DE 2016-08-11 02:00:00]",
	string(
	if VERSION >= v"1.6.0"
	"AnchoredInterval{$(repr(Day(-1))), DateTime, Open, Closed}"
	else
	"AnchoredInterval{$(repr(Day(-1))),DateTime,Open,Closed}"
	end,
	"($(repr(DateTime(2016, 8, 11, 2))))",

---

originally reported by @Ianlmgoddard

[omus]

Assuming there's no reason not to support these Periods, i believe this is just a bug in the print defintions.

There isn't a reason these aren't supported beyond a prefix letter needs to be chosen for these Period types. I do believe Microsecond and Nanosecond didn't exist when this code was originally written.

I'd also suggest defining prefix(T::Type{<:Period}) = error("A prefix for period $T has not yet been defined") or alternatively add a comment to prefix to make this behaviour clearer