TODO

Many things to do!

(1) Capture parameters in functions and capture lambdas
(2) Improve the "is" capture, the second part is ignored for now.
(3) Capture if then else
(4) Avoid comparison (<, >, =, <=, >=) in minimize/maximize scopes.
(5) Allow a single comparison in constraints.
(6) Create operator "in" to avoid function in(...)
(7) Remove keyword set from set initializer set{...}
(8) Capture minimize[ ... ] as keyword (even the [ ]) for lexicographic obj.
(9) Better organize the language tokens. Many things are done twice.
(10) ...


Keep in mind: commas are intended to separate VALUES (in parameter lists,
 sets, sequences) and semi-commas separate COMMANDS (inside constrained tuples,
sum and forall).