Recursive function

Learning
1

I have a function x that sequentially calls two other functions f1 and f1 for eg. , passes the results of f1 to f2 and repeats the process by calling itself.

let requestHandler option1 = 
  Printf.printf "Inside RequestHandler : %s\n" option1 ;
  option1
 
let valueStore option2 =
  Printf.printf "Inside valueStore : %s\n" option2
  
let rec main =
  (* print_endline(res); *)
  let vall1 = requestHandler "stringVar" in 
  valueStore vall1 ;
  main

But this throws error .

Entering directory '/home/ocaml/'
File "/client.ml", lines 13-15, characters 2-6:
13 | ..let vall1 = requestHandler "stringVar" in 
14 |   valueStore vall1 ;
15 |   main
Error: This kind of expression is not allowed as right-hand side of `let rec'
2

You can’t have a function with zero arguments. You must use unit to have this effect.
Define main as:

let rec main () = ...

and call it like this:

main ()
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3

After defining the function with unit , it compiles and executes too but doesn’t print anything, and also it terminates which should not happen as it is being called recursively.

4

Most likely you forgot to call main. If you are compiling add this as the last line:

let () = main ()
1 Like