Create a new type for Population about dispersal.jl HOT 1 OPEN

struct Phenotype_unit
    name::String
    value::Float64 # value of the trait for 1 individual
end

name(pu::Phenotype_unit) = Phenotype_unit.name
value(pu::Phenotype_unit) = Phenotype_unit.value

Base.:*(p::Phenotype_unit, x::Number) = Phenotype_unit(x*p.phenotype) 
Base.:*(x::Number, p::Phenotype_unit) = Phenotype_unit(x*p.phenotype) 
Base.:+(p::Phenotype_unit, x::Number) = Phenotype_unit(p.phenotype + x)  
Base.:+(x::Number, p::Phenotype_unit) = Phenotype_unit(p.phenotype + x)  
# Base.:+(p1::Phenotype_unit, p2::Phenotype_unit) =  ... sense ? 
Base.:-(p::Phenotype_unit, x::Number) = Phenotype_unit(p.phenotype - x) 
Base.:-(x::Number, p::Phenotype_unit) = Phenotype_unit(p.phenotype - x) 
# Base.:-(p1::Phenotype_unit, p2::Phenotype_unit) = ... # sense ?
Base.zero(::Type{<:Phenotype_unit{T}}) where {T} = Phenotype_unit(zero(T))

struct Phenotype <: AbstractIndividual
    phenotype::Array{Phenotype_unit, 1} # set of values of trait for 1 individual
    # TODO: 1. Each name of Phenotype_unit has to be unique within the phenotype vector
end

# Using genericity of Phenotype Unit
# Base.:*(p::Phenotype, x::Number) = ...
# Base.:*(x::Number, p::Phenotype) = ...

struct Population <: AbstractPopulation
    size::Float64 # Size of the population. Again an Integer could be relevant
    phenotypes::Array{Phenotype, 1} # set of values of trait for 1 individual
    # TODO: size is the length of phenotypes vector
end

size(pp::Population) = pp.size
phenotypes(pp::Population) = pp.phenotypes

struct StatsPopulation <: StatisticsPopulation
    size::Int64 
    phenotypeNames::Array{String, 1} # retrieve from Phenotype_unit
    phenotypeMean::Array{Float64, 1}
    phenotypeVariance::Array{Float64, 1}
    # TODO: INTERNAL CONSTRUCTOR based on 
end

size(sp::StatsPopulation) = sp.size
names(sp::StatsPopulation) = sp.phenotypeNames
means(sp::StatsPopulation) = sp.phenotypeMean
variances(sp::StatsPopulation) = sp.phenotypeVariance