@ocots @PierreMartinon @joseph-gergaud @j-l-s Some todo's suggestions:

• add single sided inequalities (see also Functional: revise CTBase.jl#67 as having a kwargs version of constraint! does help for this)
• add reverse inequalities (≥)
• declare time, state, control, variable simultaneously according to

(t, x, u) ∈ [ 0, 1 ] × R³ × R²
(t, x, u, v) ∈ [ 0, v₂ ] × R³ × R² × R²            # meaning that final time is free and equal to v[2] = v₂

• [ ] in place dynamics (f!(ẋ(t), x(t), u(t))) or even DAE form (F(ẋ(t), x(t), u(t)) == 0)
• [ ] for the in place form, using a keyword like

ẋ(t) == f(x(t), u(t)), inplace

• parse dynamics in several steps: x'[2](t) == ..., x'[2:4](t) == ... (each time call dynamics!, and assemble afterwards what the dynamics is...) [Feature] Dynamics components #22
• allow @Lie [ X, Y ] and @Poisson { f, g } directly (= without @) in the DSL?