Expand Just Macros (Not Includes) in C

.clang-format

BasedOnStyle: LLVM
SeparateDefinitionBlocks: Always
EmptyLineBeforeAccessModifier: LogicalBlock

expand.sh

gcc -xc -E -P -o temp.c <(sed -e '/#include/!b' -e 'w includes.txt' -e 'd' main.c) && cat includes.txt temp.c | clang-format > expanded.c

expanded.c

#include <stdio.h>
#include <stdlib.h>

typedef struct generatorCtx {
  int line;
  int i;
} generatorCtx;

int generator(generatorCtx *ctx, int n) {
  switch (ctx->line) {
  default:
    ctx->i = 0;
    for (; ctx->i < n; ctx->i++) {
      ctx->line = 20;
      return ctx->i;
    case 20:
    }
    return -1;
  }
}

int main(void) {
  generatorCtx ctx;
  ctx.line = 0;
  for (int i = 0; i < 10; i++) {
    int d = generator(&ctx, 5);
    if (d < 0)
      return 0;
    printf("Got %d\n", d);
  }
  return 0;
}

main.c

#include <stdio.h>

#define coroutine(c, r, f, a, b) typedef struct f##Ctx { \
		int line; \
		c \
	} f##Ctx; \
	r f a { \
	switch (ctx->line) { default: \
	b \
	} \
}
#define yield(x) ctx->line = __LINE__; return x; case __LINE__:
#define init(f, n) f##Ctx n; n.line = 0;

coroutine(int i;, int, generator, (generatorCtx *ctx, int n),
	ctx->i = 0;
	for (; ctx->i < n; ctx->i++) {
		yield(ctx->i)
	}
	return -1;
)

int main(void) {
	init(generator, ctx)
	for (int i = 0; i < 10; i++) {
		int d = generator(&ctx, 5);
		if (d < 0)
			return 0;
		printf("Got %d\n", d);
	}

	return 0;
}