Haclib adds higher-order, generic types to C. These include vectors (self-resizing arrays), sequences (linked lists),
and trees. These data structures are implemented as macros in headers with the base type being the first parameter,
so specific code is generated for each type and there is no overhead from tags or void pointers. Note that because of a
peculiarity in C where identical struct types are not compatible (eg struct{int i;} a; struct{int i;} b = a; will not
work), the macros *_T_NEW(base_t) must be used once before the macros *_T(base_t) to setup a typedef. Example with vectors:
#include <stdio.h>
#include "hac_vec.h"
int main(void){
HAC_VEC_T_NEW(int);
HAC_VEC_T(int) primes = HAC_VEC_LIST(int, 2);
for(int i = 2; i < 100; ++i){
if(HAC_VEC_ALL(int, &primes, i%e)){
HAC_VEC_PUSHR(int, &primes, i);
}
}
printf("%i primes:\n", (int)HAC_VEC_LEN(int, &primes));
HAC_VEC_FOREACH(int, &primes, printf("%i\n", e));
HAC_VEC_DELETE(int, &primes);
}
The code makes heavy use of statement expressions (the ({}) things), which are not standard C but supported by at least GCC and
Clang. The code also uses __typeof__(), another extension, one which could cause problems if its argument has side effects and
vm type. TCC, MSVC, Intel, and DMC compilers are untested.
The code for the data types is divided into separate files for different "typeclasses", which are only nominal but denote certain
behaviors. For example, the functor interface requires map and foreach, so these macros are placed in _hac_vec_functor.h.
To use the types, have a look at the typedefs in the *_T_NEW(base_t) macros located in the main headers
(ie the ones not beginning with an underscore). Usually you can use either vec.n or HAC_VEC_LEN(base_t, &vec) to get the
length of a vector, vec.a[i] or HAC_VEC_GET(base_t, &vec, i) to get the ith element, and so on.
Take a look at the test files to see some actual examples.
A note on debugging with macros: It is impossible to debug macros, so you will have to expand them if something goes wrong.
To do this, run GCC/Clang with -E to only do preprocessing. Before doing this, I would suggest commenting out the includes in
the haclib headers (eg stdlib.h) because they will add thousands of lines of definitions. Take them out of comments right after.
Also, you will probably only want to expand one macro, like HAC_VEC_FOREACH for instance. After your include of haclib, add
#undef s for every other macro you include. A file with all of these undefs can be found in undefs/.undefs, so copy and paste
it and remove the ones you want to expand in your source. These files are generated by the undefs/undefs.py script. Then format
the generated code so it looks pretty and compile with debugging support (-g). For instance, after removing includes and
adding the undefs, try
gcc -E -I/path/to/repo/src/ file | clang-format