Add the public Dates.periods function for getting the Vector of Periods that comprise a CompoundPeriod

NEWS.md

@@ -68,6 +68,7 @@ Standard library changes
 
 #### Dates
 
+* The `Dates.periods` function can be used to get the `Vector` of `Period`s that comprise a `CompoundPeriod` ([#39169]).
 
 #### Statistics
 

stdlib/Dates/docs/src/index.md

@@ -747,6 +747,7 @@ Dates.Period(::Any)
 Dates.CompoundPeriod(::Vector{<:Dates.Period})
 Dates.value
 Dates.default
+Dates.periods
 ```
 
 ### Rounding Functions

stdlib/Dates/src/periods.jl

@@ -196,6 +196,13 @@ struct CompoundPeriod <: AbstractTime
     end
 end
 
+"""
+    periods(::CompoundPeriod) -> Vector{Period}
+
+Return the `Vector` of `Period`s that comprise the given `CompoundPeriod`. 
+"""
+periods(x::CompoundPeriod) = x.periods
+
 """
     CompoundPeriod(periods) -> CompoundPeriod
 

stdlib/Dates/test/periods.jl

@@ -366,6 +366,7 @@ end
     @test isequal(d - h, 2d - 2h - 1d + 1h)
     @test sprint(show, y + m) == string(y + m)
     @test convert(Dates.CompoundPeriod, y) + m == y + m
+    @test Dates.periods(convert(Dates.CompoundPeriod, y)) == convert(Dates.CompoundPeriod, y).periods
 end
 @testset "compound period simplification" begin
     # reduce compound periods into the most basic form