#!/home/arne/wisp/wisp-multiline.sh 
; !#

use-modules : srfi srfi-11

define : running-stat-fun
     let
       : n 0
         sum 0
         sum² 0
       define : mean-std x
                set! n : + n 1
                set! sum : + sum x
                set! sum² : + sum² : expt x 2
                let*
                  : mean : / sum n
                    σ 
                      - : / sum² n
                        . mean
                  values mean σ
       . mean-std

define statfun : running-stat-fun

write : statfun 5
newline
write : statfun 4
newline
let-values 
    : (mean σ) : statfun 5
    display mean 
    display '±
    display σ
    newline