How do I do a pattern match on a variable that has type string option ref in OCaml. I need to extract the string part of this variable, but I can't get it to work.
OCaml match on string option ref
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1 Answers
A ref is just a record type with a mutable field called contents:
type 'a ref = { mutable contents: 'a }
So you pattern match on it just like any other record:
match foo with
| { contents = Some str } -> str
| { contents = None } -> ...
Although I would much prefer to unwrap the ref first instead of matching on it:
match !foo with
| Some str -> str
| None -> ...
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