/* See LICENSE file for copyright and license details. */
#include <libparser.h>
#include <libsimple.h>
#include <libsimple-arg.h>
USAGE("");
static void
free_input(struct libparser_unit *node)
{
struct libparser_unit *next;
for (; node; next = node->next, free(node), node = next)
free_input(node->in);
}
static intmax_t
calculate(struct libparser_unit *node, const char *line)
{
struct libparser_unit *next;
intmax_t value = 0;
int op;
if (!node->rule) {
next = node->in->next;
value = calculate(node->in, line);
free_input(next);
} else if (!strcmp(node->rule, "DIGIT")) {
value = (intmax_t)(line[node->start] - '0');
} else if (!strcmp(node->rule, "sign")) {
value = !strcmp(node->in->rule, "SUB") ? -1 : +1;
free(node->in);
} else if (!strcmp(node->rule, "unsigned")) {
value = 0;
next = node->in;
free(node);
for (node = next; node; node = next) {
next = node->next;
value *= 10;
value += calculate(node, line);
}
} else if (!strcmp(node->rule, "number")) {
next = node->in->next;
value = calculate(node->in, line);
free(node);
for (node = next; node; node = next) {
next = node->next;
value *= calculate(node, line);
}
} else if (!strcmp(node->rule, "value")) {
next = node->in->next;
value = calculate(node->in, line);
if (next)
value *= calculate(next, line);
} else if (!strcmp(node->rule, "hyper1")) {
next = node->in->next;
value = calculate(node->in, line);
free(node);
node = next;
while (node) {
next = node->next;
op = !strcmp(node->rule, "SUB") ? -1 : +1;
free(node);
node = next;
next = node->next;
if (op < 0)
value -= calculate(node, line);
else
value += calculate(node, line);
node = next;
}
} else if (!strcmp(node->rule, "hyper2")) {
next = node->in->next;
value = calculate(node->in, line);
free(node);
node = next;
while (node) {
next = node->next;
op = !strcmp(node->rule, "DIV") ? -1 : +1;
free(node);
node = next;
next = node->next;
if (op < 0)
value /= calculate(node, line);
else
value *= calculate(node, line);
node = next;
}
} else if (node->rule[0] != '@') {
abort();
} else if (node->in) {
next = node->in->next;
value = calculate(node->in, line);
if (next)
free_input(next);
}
free(node);
return value;
}
int
main(int argc, char *argv[])
{
struct libparser_unit *input;
char *line = NULL;
size_t size = 0;
ssize_t len;
intmax_t res;
int exception;
ARGBEGIN {
default:
usage();
} ARGEND;
if (argc)
usage();
while ((len = getline(&line, &size, stdin)) >= 0) {
if (len && line[len - 1] == '\n')
line[--len] = '\0';
input = libparser_parse_file(libparser_rule_table, line, (size_t)len, &exception);
if (!input) {
weprintf("didn't find anything to parse\n");
free_input(input);
continue;
} else if (input->end != (size_t)len) {
weprintf("line could not be parsed, stopped at column %zu\n", input->end);
free_input(input);
continue;
} else if (exception) {
weprintf("premature end of line\n");
free_input(input);
continue;
}
res = calculate(input, line);
printf("%ji\n", res);
}
free(line);
return 0;
}
