I'm working my way through the book, and when entering this code from pg 129 ex 4.29
let a = newarray(2, -99)
p = proc (x)
let v = arrayref(x,1)
in arrayset(x,1,-(v, -1))
arrayset(a, 1, 0);
I get " parsing: at line 3: looking for "in", found identifier p in production..."
I'm keying all my code incrementally as I work through the exercises so this could just be my bug, but when I look in the code for mutable pairs or the site, I see nothing which would suggest let should allow multiple declarations in a let. Is this really a typo?