[Ace17]

> Perhaps the biggest hurdle is that the code is not best read linearly. The reader must understand the order of evaluation, which follows very simple rules, in order to understand the code correctly.

Could you please give some details about how the order of evaluation differs from, say, C? Thanks!

[billsix]

They are very similar. They are both applicative-order, meaning that the arguments to a procedure are evaluated before the procedure is applied.

The evaluation of a lambda results in a function value, which captures the enclosing scope, but the procedure is not yet applied to anything.

But the main difference that I've seen anecdotally is that imperative programmers as a whole tend to get confused by nested expressions, or lets just say they prefer sequential statements over nested expressions. My assumption is that they don't fully understand the order of evaluation in their language of choice.

[kazinator]

Scheme and C evaluation rules are very similar: in both languages, the order of evaluation of function arguments is unspecified.

Common Lisp is left to right, so that (list (inc i) (inc i) (inc i)) will reliably produce (1 2 3) if i starts at zero.