Use := for intermediate calculations

[ChrisRackauckas]

No description provided.

[maedoc]

Is this by chance a way to use auxiliary variables? e.g. I have

using ParameterizedFunctions

f = @ode_def rww begin
    c = a + b * b
    dx = c - x
end a b

which complains that Symbolic calculations could not initiate. Likely there's a function which is not differentiable by SymEngine.

the actual model would be a 200 character line, so I don't want to write in all in one line, and auxiliary variables (as xppaut calls them) would be helpful

[ChrisRackauckas]

That's what this feature would give, but it's not implemented yet. I think we're going to just leave this as a hanging thread since this library is essentially deprecated and we encourage people to use ModelingToolkit.jl instead. But if anyone wants to take this on I'd be willing to review it.