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copied!<p>Firstly, here is a trivial example that shows how the syntax should look like:</p> <pre><code>let inline zero< ^NUM when ^NUM : (static member get_Zero: unit-> ^NUM)> (n:^NUM) = (^NUM : (static member get_Zero : unit -> ^NUM) ()) </code></pre> <p>In some cases, you don't need to write the constraints explicitly (the F# compiler will actually warn you about that if you write the above), because some static members are well-known to the compiler and there are standard functions for using them. So, you can use the function and the compiler will infer the constraint:</p> <pre><code>let inline zero (n:^T) = LanguagePrimitives.GenericZero< ^T > </code></pre> <p>Unfortunately, this really doesn't help you, because recursive functions cannot be declared as <code>inline</code> (for obvious reasons - the compiler cannot inline the function at compile time, because it doesn't know how many times), so static constraints are probably not powerful enough for your problem.</p> <p>[<strong>EDIT</strong>: This is actually possible for some functions (see kvb's answer)]</p> <p>I think you'll need <code>NumericAssociations</code> instead, which were alreaday discussed <a href="https://stackoverflow.com/questions/2225949/does-f-have-generic-arithmetic-support">in this question</a> (these are processed at runtime, so they are slower - but are used to implement for example F# matrix type - the matrix can cache the dynamically obtained information, so it is reasonably efficient).</p>

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