Question

So, I previously asked this question:

Can someone help me compare using F# over C# in this specific example (IP Address expressions)?

I was looking at the posted code and I was wondering if this code could be written without it producing a warning:

let [|a;b;c;d|] = s.Split [|'.'|]
IP(parseOrParts a, parseOrParts b, parseOrParts c, parseOrParts d)

Is it possible to do something for the match _ pattern ot ignore? Without adding in something like Active Patterns? i want to keep the code as simple as possible… can I do this without drastically changing this code?

NOTE: Warning is as follows

Warning Incomplete pattern matches on this expression. For example, the value ‘[|_; _; _; _; _|]’ may indicate a case not covered by the pattern(s).

Answer 1

You might try

#nowarn "25"

before the partial function.

But of course you’re disabling a warning, and I think this turns it off for the whole file. I remember seeing a way to disable warnings for only part of a file, but I can’t find it right now.

There is also the compiler option --nowarn:25, but this is even worse since it applies to the whole project.

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To do this the Right Way, you need to replace your two lines with three:

match Array.map parseOrParts (s.Split [|'.'|]) with
| [|a;b;c;d|] -> IP(a,b,c,d)
| _ -> failwith "Oh no!"   // preferably, your exception of choice goes here.