Yes being a CAS and a general purpose language is at odds. I guess there's two paths a) use sigils to signal that some variable should be treated as an abstrac

Yes being a CAS and a general purpose language is at odds. I guess there's two paths a) use sigils to signal that some variable should be treated as an abstract values for CAS purposes. like, :x + :x rather than x + x (or.. use sigils to signal that a variable is "normal", like $x is a normal variable and x + x is CAS stuff) b) declare CAS variables as such before using them. like with a "var" keyword or something. optionally, declare normal variables, but with a different keyword Note that formal math always look like "b)" (we declare our variables before using them), it's informal math that looks what Mathematica is doing