Replaced Base.@kwdef with @kwdef and added import Base: @kwdef in src/PowerSystems.jl for downward compatibility with Julia v1.8.x and below

Author: sambuddhac

src/PowerSystems.jl

@@ -474,6 +474,7 @@ export generate_struct_files
 #################################################################################
 # Imports
 
+import Base: @kwdef
 import LinearAlgebra
 import Unicode: normalize
 import Logging

src/models/cost_functions/HydroGenerationCost.jl

@@ -12,7 +12,7 @@ fuel curves to model specific water intake.
 
 The `variable` cost is a required parameter, but `zero(CostCurve)` can be used to set it to 0.
 """
-Base.@kwdef mutable struct HydroGenerationCost <: OperationalCost
+@kwdef mutable struct HydroGenerationCost <: OperationalCost
     "Production variable cost represented by a `FuelCurve`, where the fuel is water,
     or a `CostCurve` in currency."
     variable::ProductionVariableCostCurve

src/models/cost_functions/LoadCost.jl

@@ -10,7 +10,7 @@ fixed and variable cost components.
 
 The `variable` cost is a required parameter, but `zero(CostCurve)` can be used to set it to 0.
 """
-Base.@kwdef mutable struct LoadCost <: OperationalCost
+@kwdef mutable struct LoadCost <: OperationalCost
     "Variable cost represented as a [`CostCurve`](@ref)"
     variable::CostCurve
     "(default: 0) Fixed cost. For some cost represenations this field can be

src/models/cost_functions/MarketBidCost.jl

@@ -9,7 +9,7 @@ $(TYPEDFIELDS)
 An operating cost for market bids of energy and ancilliary services for any asset.
 Compatible with most US Market bidding mechanisms that support demand and generation side.
 """
-Base.@kwdef mutable struct MarketBidCost <: OperationalCost
+@kwdef mutable struct MarketBidCost <: OperationalCost
     "No load cost"
     no_load_cost::Union{TimeSeriesKey, Float64}
     "Start-up cost at different stages of the thermal cycle as the unit cools after a 

src/models/cost_functions/RenewableGenerationCost.jl

@@ -12,7 +12,7 @@ can be used to represent the loss of tax incentives.
 
 The `variable` cost is a required parameter, but `zero(CostCurve)` can be used to set it to 0.
 """
-Base.@kwdef mutable struct RenewableGenerationCost <: OperationalCost
+@kwdef mutable struct RenewableGenerationCost <: OperationalCost
     "Variable cost represented as a [`CostCurve`](@ref)"
     variable::CostCurve
     "(default of 0) Cost of curtailing power represented as a [`CostCurve`](@ref)"

src/models/cost_functions/StorageCost.jl

@@ -13,7 +13,7 @@ or discharge.
 This data structure is not intended to represent market storage systems market operations
 like the submission of buy/sell bids -- see [`MarketBidCost`](@ref) instead.
 """
-Base.@kwdef mutable struct StorageCost <: OperationalCost
+@kwdef mutable struct StorageCost <: OperationalCost
     "(default of 0) Variable cost of charging represented as a [`CostCurve`](@ref)"
     charge_variable_cost::CostCurve = zero(CostCurve)
     "(default of 0) Variable cost of discharging represented as a [`CostCurve`](@ref)"

src/models/cost_functions/ThermalGenerationCost.jl

@@ -8,7 +8,7 @@ $(TYPEDFIELDS)
 An operational cost for thermal generators which includes fixed cost, variable cost, shut-down
 cost, and  multiple options for start up costs.
 """
-Base.@kwdef mutable struct ThermalGenerationCost <: OperationalCost
+@kwdef mutable struct ThermalGenerationCost <: OperationalCost
     "Variable production cost. Can take a [`CostCurve`](@ref) or [`FuelCurve`](@ref)"
     variable::ProductionVariableCostCurve
     "Fixed cost of keeping the unit online. For some cost represenations this field can be

src/models/cost_functions/ValueCurves.jl

@@ -21,7 +21,7 @@ Can be used, for instance, in the representation of a [`CostCurve`](@ref) where
 and `y` is currency/hr, or in the representation of a [`FuelCurve`](@ref) where `x` is MW
 and `y` is fuel/hr.
 """
-Base.@kwdef struct InputOutputCurve{
+@kwdef struct InputOutputCurve{
     T <: Union{QuadraticFunctionData, LinearFunctionData, PiecewiseLinearData},
 } <: ValueCurve{T}
     "The underlying `FunctionData` representation of this `ValueCurve`"
@@ -42,7 +42,7 @@ cost: `y = f'(x)`. Can be used, for instance, in the representation of a [`CostC
 where `x` is MW and `y` is currency/MWh, or in the representation of a [`FuelCurve`](@ref)
 where `x` is MW and `y` is fuel/MWh.
 """
-Base.@kwdef struct IncrementalCurve{T <: Union{LinearFunctionData, PiecewiseStepData}} <:
+@kwdef struct IncrementalCurve{T <: Union{LinearFunctionData, PiecewiseStepData}} <:
               ValueCurve{T}
     "The underlying `FunctionData` representation of this `ValueCurve`"
     function_data::T
@@ -67,7 +67,7 @@ origin: `y = f(x)/x`. Can be used, for instance, in the representation of a
 [`FuelCurve`](@ref) where `x` is MW and `y` is fuel/MWh. Typically calculated by dividing
 absolute values of cost rate or fuel input rate by absolute values of electric power.
 """
-Base.@kwdef struct AverageRateCurve{T <: Union{LinearFunctionData, PiecewiseStepData}} <:
+@kwdef struct AverageRateCurve{T <: Union{LinearFunctionData, PiecewiseStepData}} <:
               ValueCurve{T}
     "The underlying `FunctionData` representation of this `ValueCurve`, in the case of `AverageRateCurve{LinearFunctionData}` representing only the oblique asymptote"
     function_data::T

src/models/cost_functions/variable_cost.jl

@@ -39,7 +39,7 @@ of a [`ValueCurve`](@ref) that may represent input-output, incremental, or avera
 data. The default units for the x-axis are MW and can be specified with
 `power_units`.
 """
-Base.@kwdef struct CostCurve{T <: ValueCurve} <: ProductionVariableCostCurve{T}
+@kwdef struct CostCurve{T <: ValueCurve} <: ProductionVariableCostCurve{T}
     "The underlying `ValueCurve` representation of this `ProductionVariableCostCurve`"
     value_curve::T
     "(default: natural units (MW)) The units for the x-axis of the curve"
@@ -78,7 +78,7 @@ liters, m^3, etc.), coupled with a conversion factor between fuel and currency.
 a [`ValueCurve`](@ref) that may represent input-output, incremental, or average rate data.
 The default units for the x-axis are MW and can be specified with `power_units`.
 """
-Base.@kwdef struct FuelCurve{T <: ValueCurve} <: ProductionVariableCostCurve{T}
+@kwdef struct FuelCurve{T <: ValueCurve} <: ProductionVariableCostCurve{T}
     "The underlying `ValueCurve` representation of this `ProductionVariableCostCurve`"
     value_curve::T
     "(default: natural units (MW)) The units for the x-axis of the curve"