[Dev] First parsing

[ocots]

@AnasXbouali This idea is to convert this

ocp = @loss_def begin

    t ∈ [ 0, tf ], time
    x ∈ R^2, state
    u ∈ R, control

    0.5 ≤  x₂(t)  ≤ 3.5, loss_region

    x₁(0) == 0
    x₂(0) == 0
    x₂(tf) == 4

    -π/2  ≤  u(t)  ≤ π/2

    ∂x₁ = x₂(t) + cos(u(t))
    ∂x₂ = sin(u(t))

    ẋ(t) == [ ∂x₁, ∂x₂ ]

    -x₁(tf) → min

end

to

ocp = @loss_def begin

    t ∈ [ 0, tf ], time
    x ∈ R^2, state
    u ∈ R, control

    x₁(0) == 0
    x₂(0) == 0
    x₂(tf) == 4

    -π/2  ≤  u(t)  ≤ π/2

    ∂x₁ = x₂(t) + cos(u(t))
    ∂x₂ = sin(u(t))

    ẋ(t) == [ ∂x₁, ∂x₂ ]

    -x₁(tf) → min

end

and then, to parse it with @def from CTBase.jl.

• Remove all the lines with loss_region tag.
• Parse the new expression with @def.

Warning

It is important to add some unit tests here.

[AnasXbouali]

Is there a precise way to define mixed (control/state) constraints? for example:

u(t)*x(t) == 1

I saw that there is CTBase.mixed_constraints!, but there isn't an example showing how to use it.

Thanks!