R Interface to the 'Uno' Nonlinear Optimization Solver // Bindings to 'Uno' (Unifying Nonlinear Optimization), a C++ solver for smooth nonlinearly constrained optimization. 'Uno' unifies Lagrange-Newton methods, including sequential quadratic programming and interior-point methods, by decomposing them into interacting building blocks (constraint-relaxation, inequality-handling, Hessian, and globalization strategies) that can be freely combined, either through options or through presets that reproduce established solvers such as 'filterSQP' and 'IPOPT'. The framework is described in Vanaret and Leyffer (2024) doi:10.48550/arXiv.2406.13454.