Parametric Field Names

General Usage
7

Seems like setproperty! is the way to go (using setfield! internally to avoid the stack-overflow).

E.g.

mutable struct Square
   side
   area
end
function Base.setproperty!(x::Square, field::Symbol, val)
  if field == :side
    setfield!(x, :side, val)
    setfield!(x, :area, val^2)
  else
    # .. or whatever else you want to do here
    error("oops!")
  end
end

s1 = Square(2,4)
s1.side = 5
println(s1.area)
# output is 25

Alternatively, you could define a set of “derrived” properties that have no fields in the struct, and override propertynames and getproperty and use those to generate the derived properties.

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