CODEWITHSUNDEEP
functional-programmingocaml
newarsenic
newarsenic

Reputation: 151

"Syntax error" while writing OCaml function?

I am writing a function in OCaml to raise x to the power of y. My code is:

#let rec pow x y =
if y == 0 then 1 else
if (y mod 2 = 0) then pow x y/2 * pow x y/2 else
x * pow x y/2 * pow x y/2;;

When I try to execute it, I get an error for syntax in line one, but it doesn't tell me what it is.

Upvotes: 0

Views: 117

Answers (1)

Del
Del

Reputation: 1329

When you wrote the code, did you type the #? The # is just a character that the OCaml REPL outputs to prompt for input; it is not part of the code. You should not type it.

Here are some other errors that you should fix:

  • == is physical equality in OCaml. = is structural equality. Although both work the same for unboxed types (such as int), it's better practice to do y = 0. Note that you use =, the recommended equality, in the expression y mod 2 = 0.
  • You need parentheses around y/2. pow x y/2 parses as (pow x y) / 2, but you want pow x (y / 2).

Upvotes: 1

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