A simple C macro to make keyword default arguments inspired by m1lkweed#4353. See main.c for examples
From main.c
pythonize(void, foo, ARGS(int x, int y), KWARGS(int a; int b)) {
printf("x: %d\ny: %d\na: %d\nb: %d\n", ARG(x), ARG(y), KWARG(a), KWARG(b));
};Once expanded will generate something equivalent to
struct func_params_foo { int sentinel_; int a; int b; };
void foo(int x, int y , struct func_params_foo *args) {
printf("x: %d\ny: %d\na: %d\nb: %d\n", x, y, args->a, args->b);
};It is important to note that ARGS(int x, int y) keeps the arguments packed together.
For invoking such a function, it should be called through the pythonic macro
pythonic(foo, 1, 2)(.a = 1);Will expand into
foo (1, 2 , (&(struct func_params_foo) { .sentinel_ = 0, .a = 1 }));While it may appear to be incredibly easy to use, it will not be as easy to debug. Your linter will most likely reject any code using pythonize instantly. A better alternative is to simply create specialized structs for yourself.
For example, if you incorrectly miss an argument
pythonize(void, foo, ARGS(int x, int y), KWARGS(int a; int b)) {
printf("x: %d\ny: %d\na: %d\nb: %d\n", ARG(x), ARG(y), KWARG(a), KWARG(b));
};
pythonic(foo, 1)(.a = 1);You'll get this horrendous error message, something right out of a badly written C++ error message
<source>:14:43: warning: passing argument 2 of 'foo' makes integer from pointer without a cast [-Wint-conversion]
14 | func_name (__VA_ARGS__ __VA_OPT__(,) (&(struct func_params_ ## func_name) { .sentinel_ = 0, wrap_pythonic
| ^
| |
| struct func_params_foo *
<source>:25:5: note: in expansion of macro 'pythonic'
25 | pythonic(foo, 1)(.a = 1); // returns 42
| ^~~~~~~~
<source>:20:38: note: expected 'int' but argument is of type 'struct func_params_foo *'
20 | pythonize(void, foo, ARGS(int x, int y), KWARGS(int a; int b)) {
| ~~~~^
<source>:12:32: note: in definition of macro 'pythonize_II'
12 | function_ret function_name(__VA_ARGS__ __VA_OPT__(,) struct func_params_ ## function_name *args)
| ^~~~~~~~~~~
<source>:5:62: note: in expansion of macro 'pythonize_I'
5 | #define pythonize(function_ret, function_name, args, kwargs) pythonize_I(function_ret, function_name, kwargs, args)
| ^~~~~~~~~~~
<source>:20:1: note: in expansion of macro 'pythonize'
20 | pythonize(void, foo, ARGS(int x, int y), KWARGS(int a; int b)) {
| ^~~~~~~~~
<source>:20:22: note: in expansion of macro 'ARGS'
20 | pythonize(void, foo, ARGS(int x, int y), KWARGS(int a; int b)) {
| ^~~~
<source>:25:14: error: too few arguments to function 'foo'
25 | pythonic(foo, 1)(.a = 1); // returns 42
| ^~~
<source>:14:5: note: in definition of macro 'pythonic'
14 | func_name (__VA_ARGS__ __VA_OPT__(,) (&(struct func_params_ ## func_name) { .sentinel_ = 0, wrap_pythonic
| ^~~~~~~~~
<source>:20:17: note: declared here
20 | pythonize(void, foo, ARGS(int x, int y), KWARGS(int a; int b)) {
| ^~~
<source>:12:18: note: in definition of macro 'pythonize_II'
12 | function_ret function_name(__VA_ARGS__ __VA_OPT__(,) struct func_params_ ## function_name *args)
| ^~~~~~~~~~~~~
<source>:5:62: note: in expansion of macro 'pythonize_I'
5 | #define pythonize(function_ret, function_name, args, kwargs) pythonize_I(function_ret, function_name, kwargs, args)
| ^~~~~~~~~~~
<source>:20:1: note: in expansion of macro 'pythonize'
20 | pythonize(void, foo, ARGS(int x, int y), KWARGS(int a; int b)) {
| ^~~~~~~~~
So save yourself the trouble and resist the temptation to make a macro to make anything similar to this.
If you want to use this anyway, be my guest. Adding pragma to disable warnings around the code using pythonize can be a start.
If you wish to inquire further about this code, contact me through discord.
Discord - (traits*)sbrk(sizeof *traits)#1732