while(<>){
	if( /IF\(expr1,expr2,expr3\)/ ) { 
		if( rand() > 0.1 ) {
			s/IF\(expr1,expr2,expr3\)/CASE\nWHEN condition THEN result\n[ WHEN condition THEN result ]...\n[ ELSE result ]\nEND\n/;
		} else {
			s/IF\(expr1,expr2,expr3\)/CASE expression\nWHEN value THEN result\n[ WHEN value THEN result ]...\n[ ELSE result ]\nEND\n/;
		}
	}
}