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|
%{
#define _XOPEN_SOURCE 700
#include <locale.h>
#include <string.h>
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <inttypes.h>
typedef struct {
int type;
union {
intmax_t i;
char *s;
} u;
} expr_yystype;
static char **expr_args;
static int expr_end = 0;
#define YYSTYPE expr_yystype
static int yylex(void);
static int yyerror(const char *s);
static void expr_only_integers(YYSTYPE *y1, YYSTYPE *y2);
static int expr_compare(YYSTYPE *y1, YYSTYPE *y2);
static void expr_print(YYSTYPE *y1);
%}
%token INTEGER
%token STRING
%token '(' ')'
%left ':'
%left '*' '/' '%'
%left '+' '-'
%left '=' '<' '>' LE GE NE
%left '&'
%left '|'
%start expr
%%
expr : STRING {
expr_print(&$1);
}
| INTEGER {
expr_print(&$1);
}
| '(' expr ')' {
$$ = $2;
return $$.type;
}
| expr ':' expr {
printf("match\n");
/* TODO: number of initial characters in $1.u.s matching re $2.u.s */
}
| expr '*' expr {
expr_only_integers(&$1, &$3);
$$.u.i = $1.u.i * $3.u.i;
expr_print(&$$);
return $$.type;
}
| expr '/' expr {
expr_only_integers(&$1, &$3);
$$.u.i = $1.u.i / $3.u.i;
expr_print(&$$);
return $$.type;
}
| expr '%' expr {
expr_only_integers(&$1, &$3);
$$.u.i = $1.u.i % $3.u.i;
expr_print(&$$);
return $$.type;
}
| expr '+' expr {
expr_only_integers(&$1, &$3);
$$.u.i = $1.u.i + $3.u.i;
expr_print(&$$);
return $$.type;
}
| expr '-' expr {
expr_only_integers(&$1, &$3);
$$.u.i = $1.u.i - $3.u.i;
expr_print(&$$);
return $$.type;
}
| expr '=' expr {
$$.type = INTEGER;
$$.u.i = expr_compare(&$1, &$3) == 0;
expr_print(&$$);
return $$.type;
}
| expr NE expr {
$$.type = INTEGER;
$$.u.i = expr_compare(&$1, &$3) != 0;
expr_print(&$$);
return $$.type;
}
| expr '<' expr {
$$.type = INTEGER;
$$.u.i = expr_compare(&$1, &$3) < 0;
expr_print(&$$);
return $$.type;
}
| expr LE expr {
$$.type = INTEGER;
$$.u.i = expr_compare(&$1, &$3) <= 0;
expr_print(&$$);
return $$.type;
}
| expr '>' expr {
$$.type = INTEGER;
$$.u.i = expr_compare(&$1, &$3) > 0;
expr_print(&$$);
return $$.type;
}
| expr GE expr {
$$.type = INTEGER;
$$.u.i = expr_compare(&$1, &$3) >= 0;
expr_print(&$$);
return $$.type;
}
| expr '&' expr {
printf("and\n");
}
| expr '|' expr {
printf("or\n");
}
;
%%
static void expr_print(YYSTYPE *y1)
{
if (!expr_end) {
return;
}
if (y1->type == INTEGER) {
printf("%jd\n", y1->u.i);
} else {
printf("%s\n", y1->u.s);
}
}
static void expr_only_integers(YYSTYPE *y1, YYSTYPE *y2)
{
if (y1->type == STRING) {
fprintf(stderr, "expr: %s is not an integer\n", y1->u.s);
exit(1);
}
if (y2->type == STRING) {
fprintf(stderr, "expr: %s is not an integer\n", y2->u.s);
exit(1);
}
}
static int expr_compare(YYSTYPE *y1, YYSTYPE *y2)
{
if (y1->type == INTEGER && y2->type == INTEGER) {
return y1->u.i - y2->u.i;
}
char buf[64];
char *s1 = y1->u.s;
char *s2 = y2->u.s;
if (y1->type == INTEGER) {
snprintf(buf, sizeof(buf), "%jd", y1->u.i);
s1 = buf;
} else if (y2->type == INTEGER) {
snprintf(buf, sizeof(buf), "%jd", y2->u.i);
s2 = buf;
}
return strcmp(s1, s2);
}
static int yylex(void)
{
if (expr_args[optind] == NULL) {
expr_end = 1;
return 0;
}
char *s = expr_args[optind];
if (strlen(s) == 1) {
char c = s[0];
if (strchr("|&=+-*/%():", c)) {
optind++;
return c;
}
}
if (strlen(s) == 2) {
if (!strcmp(s, ">=")) {
optind++;
return GE;
}
if (!strcmp(s, "<=")) {
optind++;
return LE;
}
if (!strcmp(s, "!=")) {
optind++;
return NE;
}
}
char *end = NULL;
yylval.type = INTEGER;
yylval.u.i = strtoimax(s, &end, 10);
if (end && *end != '\0') {
yylval.type = STRING;
yylval.u.s = s;
}
optind++;
return yylval.type;
}
static int yyerror(const char *s)
{
fprintf(stderr, "expr: %s\n", s);
return 0;
}
int main(int argc, char *argv[])
{
setlocale(LC_ALL, "");
int c;
while ((c = getopt(argc, argv, "")) != -1) {
switch (c) {
default:
return -1;
}
}
if (optind >= argc) {
fprintf(stderr, "expr: missing operands\n");
return 1;
}
expr_args = argv;
return yyparse();
}
|
