add @constantvalue macro

src/shared_utilities/Parameters.jl

@@ -26,9 +26,8 @@ Base.@kwdef struct LandParameters{FT, TP, SFP, IP} <: ALP
     surf_flux_params::SFP
     insol_params::IP
 end
-
 Base.eltype(::LandParameters{FT}) where {FT} = FT
-Base.broadcastable(ps::LandParameters) = tuple(ps)
+@ConstantValue LandParameters
 
 # wrapper methods:
 P_ref(ps::ALP) = ps.MSLP

src/shared_utilities/utils.jl

@@ -3,7 +3,7 @@ import SciMLBase
 import ClimaDiagnostics.Schedules: EveryCalendarDtSchedule
 import Dates
 
-export FTfromY
+export FTfromY, @ConstantValue
 
 """
      heaviside(x::FT)::FT where {FT}
@@ -492,3 +492,24 @@ function isdivisible(
     # have any common divisor)
     return isinteger(Dates.Day(1) / dt_small)
 end
+
+"""
+    ConstantValue(T)
+
+This macro defines functions required for broadcasting over an object.
+This is a more complete approach than just defining `broadcastable` for an
+object, and avoids type inference failures when broadcasting over multiple
+complex objects.
+
+Usage:
+- `@ConstantValue T`, as opposed to e.g. `Base.broadcastable(x::T) = tuple(x)`
+"""
+macro ConstantValue(T)
+    quote
+        Base.broadcastable(x::$T) = x
+        Base.axes(x::$T) = ()
+        Base.getindex(x::$T, i...) = x
+        Base.getindex(x::$T, i) = x
+        Base.ndims(x::Type{<:$T}) = 0
+    end
+end

src/standalone/Soil/retention_models.jl

@@ -42,6 +42,7 @@ function vanGenuchten{FT}(; α::FT, n::FT) where {FT}
     S_c = (1 + ((n - 1) / n)^(1 - 2 * n))^(-m)
     return vanGenuchten{FT}(α, n, m, S_c)
 end
+@ConstantValue vanGenuchten
 
 """
    BrooksCorey{FT} <: AbstractSoilHydrologyClosure{FT}