loop comefrom

comefrom.cp

#include <stdio.h>

int main(int argc, char **argv) {
	int i = 10;

	comefrom loop;
	if(i < 0) {
		stop:;
	}

	printf("%d\n", i--);

	loop:

	comefrom stop;
	printf("done\n");
	return 0;
}

compile.sh

#!/usr/bin/bash

if [[ ! -f "$1" ]] || [[ -n "$2" ]]; then
	echo "usage: $0 <file.cf>"
	exit 0
fi

{
	echo "// secret comefrom sauce"
	echo "#define comefrom(x) x:"
	echo "#define alabel(x) goto x;"
	echo ""
	sed -r \
		-e 's/([^ \t]*):/alabel(\1);/' \
		-e 's/comefrom ([^ ]*);/comefrom(\1);/' \
		"$1"
} > out.c

gcc out.c

out.c

// secret comefrom sauce
#define comefrom(x) x:
#define alabel(x) goto x;

#include <stdio.h>

int main(int argc, char **argv) {
	int i = 10;

	comefrom(loop);
	if(i < 0) {
		alabel(stop);;
	}

	printf("%d\n", i--);

	alabel(loop);

	comefrom(stop);
	printf("done\n");
	return 0;
}