What kind of evidence do you have for this claim? The amount of copying in a functional or imperative program depends on how they're written, how they're optimi

What kind of evidence do you have for this claim? The amount of copying in a functional or imperative program depends on how they're written, how they're optimized, and how they've compiled or evaluated. For example, in programs with mutable state, it's not uncommon for modules to return deep copies of objects to avoid mutation-related bugs. Java's String objects are immutable precisely to avoid having to do this.