Question about how to get the value of function

[Hsiu-Hao Tsao]

Hello guile users ,

 

I am new to scheme and sorry to ask a newbie question.

 

I want to let function return the value , for example , in Drscheme :

 

>(define add2 (lambda (i) (+ i i)))

>(add2 2)

4

 

I type (add2 2) in command line and it will return a value 4.

 

But when I type my function foo in the command line

 

>(define y '(1 2 3 4))

>(define dt 1)

>(define foo
      (lambda (t) (do ((i 0 (+ i 1))) ((> i 3)) (if (and (>= t 0) (and (>= t (* i dt)) (< t (* (+ i 1) dt)))) (list-ref y i) #f))))

 

>(foo 0)  ---->this should return 1 , but there is no value to come out.

 

>(foo 1)  ---->this should return 2

.

.

.

and so on.

 

Can anyone tell me how to solve this problem ? I really appreciate your knowledge and hope I won't cause your inconvenience.

 

Best Regards ,

 

Hsiu-Hao Tsao

 

Master Student

 

Ultrafast Photonics Laboratory ,
Institute Photonics of Technologies ,
National Tsing Hua University , Taiwan

 

Lab : +8863-5715131-34178
Office : +8863-5715131-34007
Cell Phone : +886920158033