doc-src/Codegen/Thy/examples/arbitrary.ML

try to avoid races again (cf. 8c37cb84065f and fd3a36e48b09);

structure Codegen = 
struct

val arbitrary_option : 'a option = NONE;

fun dummy_option [] = arbitrary_option
  | dummy_option (x :: xs) = SOME x;

end; (*struct Codegen*)