[neonscribe]

Dynamic scoping is usually implemented with shallow binding, where a single value cell for a variable is located at a fixed address, with each new binding saving and restoring the enclosing value on the stack. This allows constant time variable access, even in an interpreter working directly from S-expressions without a compilation phase. Lexical scoping in a pure interpreter requires a linear search through an environment. In compiled code, lexically-scoped variable access is more efficient than dynamically-scoped variable access, since it can be implemented with either a stack location at a fixed offset in the frame, or inside a closure object at a fixed offset.