gistfile1.txt

$ ./gosh -ftest ./t
Benchmark: ran giterate0, giterate0-1, giterate1, giterate2, gunfold1, each for 10 times.
    giterate0: 14.336 real, 21.140 cpu (20.990 user + 0.150 sys)@0.47/s n=10
  giterate0-1:  6.291 real,  6.290 cpu ( 6.290 user + 0.000 sys)@1.59/s n=10
    giterate1:  7.002 real,  7.000 cpu ( 7.000 user + 0.000 sys)@1.43/s n=10
    giterate2:  5.903 real,  5.910 cpu ( 5.910 user + 0.000 sys)@1.69/s n=10
     gunfold1: 14.704 real, 14.720 cpu (14.710 user + 0.010 sys)@0.68/s n=10

              Rate giterate0 giterate0-1 giterate1 giterate2 gunfold1
    giterate0  0/s        --       0.298     0.331     0.280    0.696
  giterate0-1  2/s     3.361          --     1.113     0.940    2.340
    giterate1  1/s     3.020       0.899        --     0.844    2.103
    giterate2  2/s     3.577       1.064     1.184        --    2.491
     gunfold1  1/s     1.436       0.427     0.476     0.401       --
     

t.scm

(use gauche.time)
(use gauche.generator)

(define (giterate0 f x)
  (^[]
    (begin0 x
      (set! x (f x)))))

(define (giterate0-1 f x)
  (^[]
    (rlet1 x_ x
      (set! x (f x)))))

(define (giterate1 f x)
  (gcons* x
          (^[]
            (set! x (f x))
            x)))

(define (giterate2 f x)
  (^[]
    (set! x (f x))
    x))

(define (gunfold1 f x)
  (gunfold (^_ #f) identity f x))

(define (runner proc)
  (^[] ((gdrop (proc (cut + 1 <>) 1) 10000000))))

(define (main args)
  (time-these/report
   10
   `((giterate0   . ,(runner giterate0))
     (giterate0-1 . ,(runner giterate0-1)) 
     (giterate1   . ,(runner giterate1))
     (giterate2   . ,(runner giterate2))
     (gunfold1    . ,(runner gunfold1))
     )))