citizen428/Makefile

## abuse.c
#include <netinet/in.h>
#include <stdio.h>
#include <string.h>
#include <unistd.h>

#include "abuse.h"

// clang-format off
#define WATER_CSS "https://cdn.jsdelivr.net/npm/water.css@2/out/water.css"

#define HTML                                                              \
  head(                                                                   \
    tag(title, C Preprocessor Abuse)                                      \
    link(_(rel="stylesheet" href=WATER_CSS))                              \
  )                                                                       \
  body(                                                                   \
    div(attr(class, "container"),                                         \
      h1(, C Preprocessor Abuse)                                          \
      hr                                                                  \
      p(, This page was generated entirely by the C preprocessor.)        \
      p(, HTML tags are defined as function-like macros that expand to    \
          angle-bracket syntax. The entire page is a single string        \
          literal assembled at compile time via token stringification.)   \
      tag(blockquote, tag(em, The compiler is the template engine.))      \
      hr                                                                  \
    )                                                                     \
  )
// clang-format on

int main(void) {
  char *response = "HTTP/1.1 200 OK\r\n"
                   "Content-Type: text/html\r\n"
                   "\r\n" html(HTML);

  int fd = socket(AF_INET, SOCK_STREAM, 0);
  int opt = 1;
  setsockopt(fd, SOL_SOCKET, SO_REUSEADDR, &opt, sizeof(opt));

  struct sockaddr_in addr = {
      .sin_family = AF_INET,
      .sin_port = htons(8080),
      .sin_addr.s_addr = htonl(INADDR_LOOPBACK),
  };
  bind(fd, (struct sockaddr *)&addr, sizeof(addr));
  listen(fd, 1);

  puts("Listening on http://localhost:8080");

  while (true) {
    int client = accept(fd, NULL, NULL);
    char buf[1024];
    read(client, buf, sizeof(buf));
    write(client, response, strlen(response));
    close(client);
  }
}

## abuse.h
#define _(...) __VA_ARGS__

#define html_(x) "<html>" #x "</html>"
#define html(x) html_(x)

#define tag(name, x) <name>x</name>
#define tag_attr(name, attrs, x) <name attrs>x</name>
#define tag_void(name, attrs) <name attrs>
#define attr(name, value) name = value

#define head(x) tag(head, x)
#define link(attrs) tag_void(link, attrs)

#define body(x) tag(body, x)
#define div(attrs, x) tag_attr(div, attrs, x)
#define h1(attrs, x) tag_attr(h1, attrs, x)
#define hr <hr />
#define p(attrs, x) tag_attr(p, attrs, x)

## Makefile
CC ?= clang
CFLAGS = -std=c23 -Wall -Werror

run: clean abuse
	@./abuse

abuse:
	@$(CC) $(CFLAGS) -I. -o abuse abuse.c

clean:
	@rm -f ./abuse

.PHONY: clean run
	#include <netinet/in.h>
	#include <stdio.h>
	#include <string.h>
	#include <unistd.h>

	#include "abuse.h"

	// clang-format off
	#define WATER_CSS "https://cdn.jsdelivr.net/npm/water.css@2/out/water.css"

	#define HTML \
	head( \
	tag(title, C Preprocessor Abuse) \
	link(_(rel="stylesheet" href=WATER_CSS)) \
	) \
	body( \
	div(attr(class, "container"), \
	h1(, C Preprocessor Abuse) \
	hr \
	p(, This page was generated entirely by the C preprocessor.) \
	p(, HTML tags are defined as function-like macros that expand to \
	angle-bracket syntax. The entire page is a single string \
	literal assembled at compile time via token stringification.) \
	tag(blockquote, tag(em, The compiler is the template engine.)) \
	hr \
	) \
	)
	// clang-format on

	int main(void) {
	char *response = "HTTP/1.1 200 OK\r\n"
	"Content-Type: text/html\r\n"
	"\r\n" html(HTML);

	int fd = socket(AF_INET, SOCK_STREAM, 0);
	int opt = 1;
	setsockopt(fd, SOL_SOCKET, SO_REUSEADDR, &opt, sizeof(opt));

	struct sockaddr_in addr = {
	.sin_family = AF_INET,
	.sin_port = htons(8080),
	.sin_addr.s_addr = htonl(INADDR_LOOPBACK),
	};
	bind(fd, (struct sockaddr *)&addr, sizeof(addr));
	listen(fd, 1);

	puts("Listening on http://localhost:8080");

	while (true) {
	int client = accept(fd, NULL, NULL);
	char buf[1024];
	read(client, buf, sizeof(buf));
	write(client, response, strlen(response));
	close(client);
	}
	}
	#define _(...) __VA_ARGS__

	#define html_(x) "<html>" #x "</html>"
	#define html(x) html_(x)

	#define tag(name, x) <name>x</name>
	#define tag_attr(name, attrs, x) <name attrs>x</name>
	#define tag_void(name, attrs) <name attrs>
	#define attr(name, value) name = value

	#define head(x) tag(head, x)
	#define link(attrs) tag_void(link, attrs)

	#define body(x) tag(body, x)
	#define div(attrs, x) tag_attr(div, attrs, x)
	#define h1(attrs, x) tag_attr(h1, attrs, x)
	#define hr <hr />
	#define p(attrs, x) tag_attr(p, attrs, x)
	CC ?= clang
	CFLAGS = -std=c23 -Wall -Werror

	run: clean abuse
	@./abuse

	abuse:
	@$(CC) $(CFLAGS) -I. -o abuse abuse.c

	clean:
	@rm -f ./abuse

	.PHONY: clean run