It's not a comparison either. OP's statement is just wrong; the obvious meaning of = is equality. For the definition of a pure function, = is the obvious symbol to use since the RHS can be substituted in for the LHS in any context.
-> for definition is just annoying. On every keyboard layout, it takes two strikes to type, possibly with shift involved.
Use ≟ for comparison. I don't know where to find it on my keyboard, though. Maybe language designers should invent a keyboard along with their language.
-> for definition is just annoying. On every keyboard layout, it takes two strikes to type, possibly with shift involved.