// "./cfa prolog.c" extern "C" { extern int printf( const char *fmt, ... ); } void printResult( int x ) { printf( "int\n" ); } void printResult( double x ) { printf( "double\n" ); } void printResult( char * x ) { printf( "char*\n" ); } void is_arithmetic( int x ) {} void is_arithmetic( double x ) {} void is_integer( int x ) {} context ArithmeticType( type T ) { void is_arithmetic( T ); }; context IntegralType( type T | ArithmeticType( T ) ) { void is_integer( T ); }; forall( type T | IntegralType( T ) | { void printResult( T ); } ) void hornclause( T param ) { printResult( param ); } int main() { int x; double x; char * x; hornclause( x ); }