Since code-is-data, you can put that exact if statement into several functions. Since code-is-data, you can swap the if and else clauses around. This applies t

Since code-is-data, you can put that exact if statement into several functions. Since code-is-data, you can swap the if and else clauses around. This applies to all the functions where you've inserted the if statement. This kind of thing makes it difficult to compile a function to a fast set of machine instructions with the same effect. Not impossible, but difficult.