so, I have the following form in some code I wrote:

(let [[rightOperand operands] (pop operands)]
     (let [[leftOperand operands] (pop operands)]
           (recur operators (push operands ( list operator leftOperand rightOperand)))
     ))

is this pattern of nested lets a code smell or a common pattern?

FWIW: (defn pop [c] [(first c) (rest c)])

It’s not common; let forms allow multiple bindings that are evaluated in order and can refer to prior bindings

The rebinding of operands might be confusing, but it could be a reasonable choice

so

(let [[rightOperand operands] (pop operands)
[leftOperand operands] (pop operands)] … )

would be OK?

in this case, the rebind makes sense… i’m trying to implement the pop off a stack

so returning the popped value and the new stack

thanks, by the way

Yeah, that should work

it did!

thanks

working through Clojure for the Brave & True and finally completed the infix->prefix converter in Chapter 7

@dancrumb: that was the hardest exercise so far for me 😉 I even had to look up the shunting-yard algorithm

@zzamboni: yeah! i’d actually heard of the algorithm and dug out a really nice SO answer that described it. implementing it was… interesting… but really satisfying once i got there

crontab l