An option is a type that can potentially hold a value. In other words, it is used to represent a situation where there may or may not be a value. It is similar to Option<T> in rust or Nullable<T> in C#.
Unlike most of the other data structures included in this library, all of the functions related to Option pass their arguments by value instead of through a pointer.
OPTION_DEFINE_H(type_name, function_prefix, value_type)
| Name | Description |
|---|---|
| type_name | The name of the generated type. |
| function_prefix | The name to prefix the map functions with. |
| value_type | The type that can potentially be held by the option. |
These shouldn’t be accessed directly. Instead, use the corresponding functions (which should be inlined) or macros. However, they’re documented just in case.
| Name | Type | Description |
|---|---|---|
| value | value_type | The value held by the option. |
| has_value | bool | Determines if the option has a value or not. |
#include <generic_option.h>
OPTION_DEFINE_H(StringOption, str_opt, char*)
StringOption none = str_opt_default();
StringOption some = str_opt_make("Hello World");
printf("none has value? %s\n", str_opt_has_value(none) ? "true" : "false");
printf("some has value? %s\n", str_opt_has_value(some) ? "true" : "false");
printf("somes value: %s\n", str_opt_value(some));
// Output:
// none has value? false
// some has value? true
// somes value: Hello World