You might like Structure and Interpretation of Classical Mechanics by Sussman and Wisdom. It does classical mechanics using an MIT-Scheme library.

Lean/mathlib is a mix of functional programming and classical math notation. The community likes unicode quite a lot, with support by the editor (using quasi-Latex input methods in both VS Code and emacs). Here's an example from graph theory (I removed some conceptually irrelevant parts):

  theorem simple_graph.sum_degrees_eq_twice_card_edges (G : simple_graph V) [fintype V] :
    ∑ (v : V), G.degree v = 2 * G.edge_finset.card