SWIG example of multiple typechecks with different pecedences.

typecheck_eg.i

%typemap(typecheck, precedence=5000)(MyComplex) {
$1 = QuicklyCheckIfReallyIsMyComplex($input);
}
%typemap(typecheck, precedence=5500)(MyDouble) {
$1 = QuicklyCheckIfReallyIsMyDouble($input);
}
%typemap(typecheck, precedence=6000)(MyDouble) {
$1 = LongCheckToSeeIfCanBeConvertedToADouble($input);
}
%typemap(typecheck, precedence=6500)(MyComplex) {
$1 = LongCheckToSeeIfCanBeConvertedToAComplex($input);
}

%typemap(in)(MyDouble) { $1 = ProcessMyDouble($input); }
%typemap(in)(MyComplex) { $1 = ProcessMyComplex($input); }

MyDouble f(MyDouble x) { return x; }
MyComplex f(MyComplex x) { return x; }

This is compiled with:

swig -module mod -c++ -o typecheck_wrap.cpp -python typecheck_eg.i