NetBSD/bin/expr/expr.y

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%{
/* Written by Pace Willisson (pace@blitz.com)
* and placed in the public domain
*
* PATCHES MAGIC LEVEL PATCH THAT GOT US HERE
* -------------------- ----- ----------------------
* CURRENT PATCH LEVEL: 1 00092
* -------------------- ----- ----------------------
*
* 15 Mar 93 J.T. Conklin Added support for parens, string
* expressions that are numeric, and
* fixed division by zero.
* Enhanced performance and memory use.
*/
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <ctype.h>
enum valtype {
integer, string
} ;
struct val {
enum valtype type;
union {
char *s;
int i;
} u;
};
struct val *result;
struct val *op_or ();
struct val *op_and ();
struct val *op_eq ();
struct val *op_gt ();
struct val *op_lt ();
struct val *op_ge ();
struct val *op_le ();
struct val *op_ne ();
struct val *op_plus ();
struct val *op_minus ();
struct val *op_times ();
struct val *op_div ();
struct val *op_rem ();
struct val *op_colon ();
char **av;
%}
%union
{
struct val *val;
}
%left <val> '|'
%left <val> '&'
%left <val> '=' '>' '<' GE LE NE
%left <val> '+' '-'
%left <val> '*' '/' '%'
%left <val> ':'
%left UNARY
%token <val> TOKEN
%type <val> start expr
%%
start: expr { result = $$; }
expr: TOKEN
| '(' expr ')' { $$ = $2; }
| expr '|' expr { $$ = op_or ($1, $3); }
| expr '&' expr { $$ = op_and ($1, $3); }
| expr '=' expr { $$ = op_eq ($1, $3); }
| expr '>' expr { $$ = op_gt ($1, $3); }
| expr '<' expr { $$ = op_lt ($1, $3); }
| expr GE expr { $$ = op_ge ($1, $3); }
| expr LE expr { $$ = op_le ($1, $3); }
| expr NE expr { $$ = op_ne ($1, $3); }
| expr '+' expr { $$ = op_plus ($1, $3); }
| expr '-' expr { $$ = op_minus ($1, $3); }
| expr '*' expr { $$ = op_times ($1, $3); }
| expr '/' expr { $$ = op_div ($1, $3); }
| expr '%' expr { $$ = op_rem ($1, $3); }
| expr ':' expr { $$ = op_colon ($1, $3); }
| '-' expr %prec UNARY { $$ = op_minus (NULL, $2); }
;
%%
struct val *
make_integer (i)
int i;
{
struct val *vp;
vp = malloc (sizeof (*vp));
if (vp == NULL) {
fprintf (stderr, "expr: out of memory\n");
exit (2);
}
vp->type = integer;
vp->u.i = i;
return vp;
}
struct val *
make_str (s)
char *s;
{
struct val *vp;
vp = malloc (sizeof (*vp));
if (vp == NULL || ((vp->u.s = strdup (s)) == NULL)) {
fprintf (stderr, "expr: out of memory\n");
exit (2);
}
vp->type = string;
return vp;
}
void
free_value (vp)
struct val *vp;
{
if (vp->type == string)
free (vp->u.s);
}
int
to_integer (vp)
struct val *vp;
{
char *s;
int neg;
int i;
if (vp->type == integer)
return 1;
s = vp->u.s;
i = 0;
neg = (*s == '-');
if (neg)
s++;
for (;*s; s++) {
if (!isdigit (*s))
return 0;
i *= 10;
i += *s - '0';
}
free (vp->u.s);
if (neg)
i *= -1;
vp->type = integer;
vp->u.i = i;
return 1;
}
void
to_string (vp)
struct val *vp;
{
char *tmp;
if (vp->type == string)
return;
tmp = malloc (25);
if (tmp == NULL) {
fprintf (stderr, "expr: out of memory\n");
exit (2);
}
sprintf (tmp, "%d", vp->u.i);
vp->type = string;
vp->u.s = tmp;
}
int
isstring (vp)
struct val *vp;
{
return (vp->type == string);
}
int
yylex ()
{
struct val *vp;
char *p;
if (*av == NULL)
return (0);
p = *av++;
if (strlen (p) == 1) {
if (strchr ("|&=<>+-*/%:()", *p))
return (*p);
} else if (strlen (p) == 2 && p[1] == '=') {
switch (*p) {
case '>': return (GE);
case '<': return (LE);
case '!': return (NE);
}
}
yylval.val = make_str (p);
return (TOKEN);
}
int
is_zero_or_null (vp)
struct val *vp;
{
if (vp->type == integer) {
if (vp->u.i == 0)
return (1);
} else {
if (*vp->u.s == 0)
return (1);
}
return (0);
}
void
main (argc, argv)
int argc;
char **argv;
{
av = argv + 1;
yyparse ();
if (result->type == integer)
printf ("%d\n", result->u.i);
else
printf ("%s\n", result->u.s);
if (is_zero_or_null (result))
exit (1);
else
exit (0);
}
int
yyerror (s)
char *s;
{
fprintf (stderr, "expr: syntax error\n");
exit (2);
}
struct val *
op_or (a, b)
struct val *a, *b;
{
if (is_zero_or_null (a)) {
free_value (a);
return (b);
} else {
free_value (b);
return (a);
}
}
struct val *
op_and (a, b)
struct val *a, *b;
{
if (is_zero_or_null (a) || is_zero_or_null (b)) {
free_value (a);
free_value (b);
return (make_integer (0));
} else {
free_value (b);
return (a);
}
}
struct val *
op_eq (a, b)
struct val *a, *b;
{
struct val *r;
/* attempt to coerce both arguments to integers */
(void) to_integer (a);
(void) to_integer (b);
/* But if either one of them really is a string, do
a string comparison */
if (isstring (a) || isstring (b)) {
to_string (a);
to_string (b);
r = make_integer (strcmp (a->u.s, b->u.s) == 0);
} else {
r = make_integer (a->u.i == b->u.i);
}
free_value (a);
free_value (b);
return r;
}
struct val *
op_gt (a, b)
struct val *a, *b;
{
struct val *r;
/* attempt to coerce both arguments to integers */
(void) to_integer (a);
(void) to_integer (b);
/* But if either one of them really is a string, do
a string comparison */
if (isstring (a) || isstring (b)) {
to_string (a);
to_string (b);
r = make_integer (strcmp (a->u.s, b->u.s) > 0);
} else {
r= make_integer (a->u.i > b->u.i);
}
free_value (a);
free_value (b);
return r;
}
struct val *
op_lt (a, b)
struct val *a, *b;
{
struct val *r;
/* attempt to coerce both arguments to integers */
(void) to_integer (a);
(void) to_integer (b);
/* But if either one of them really is a string, do
a string comparison */
if (isstring (a) || isstring (b)) {
to_string (a);
to_string (b);
r = make_integer (strcmp (a->u.s, b->u.s) < 0);
} else {
r = make_integer (a->u.i < b->u.i);
}
free_value (a);
free_value (b);
return r;
}
struct val *
op_ge (a, b)
struct val *a, *b;
{
struct val *r;
/* attempt to coerce both arguments to integers */
(void) to_integer (a);
(void) to_integer (b);
/* But if either one of them really is a string, do
a string comparison */
if (isstring (a) || isstring (b)) {
to_string (a);
to_string (b);
r = make_integer (strcmp (a->u.s, b->u.s) >= 0);
} else {
r = make_integer (a->u.i >= b->u.i);
}
free_value (a);
free_value (b);
return r;
}
struct val *
op_le (a, b)
struct val *a, *b;
{
struct val *r;
/* attempt to coerce both arguments to integers */
(void) to_integer (a);
(void) to_integer (b);
/* But if either one of them really is a string, do
a string comparison */
if (isstring (a) || isstring (b)) {
to_string (a);
to_string (b);
r = make_integer (strcmp (a->u.s, b->u.s) <= 0);
} else {
r = make_integer (a->u.i <= b->u.i);
}
free_value (a);
free_value (b);
return r;
}
struct val *
op_ne (a, b)
struct val *a, *b;
{
struct val *r;
/* attempt to coerce both arguments to integers */
(void) to_integer (a);
(void) to_integer (b);
/* But if either one of them really is a string, do
a string comparison */
if (isstring (a) || isstring (b)) {
to_string (a);
to_string (b);
r = make_integer (strcmp (a->u.s, b->u.s) != 0);
} else {
r = make_integer (a->u.i != b->u.i);
}
free_value (a);
free_value (b);
return r;
}
struct val *
op_plus (a, b)
struct val *a, *b;
{
struct val *r;
if (!to_integer (a) || !to_integer (b)) {
fprintf (stderr, "expr: non-numeric argument\n");
exit (2);
}
r = make_integer (a->u.i + b->u.i);
free_value (a);
free_value (b);
return r;
}
struct val *
op_minus (a, b)
struct val *a, *b;
{
struct val *r;
if (!to_integer (a) || !to_integer (b)) {
fprintf (stderr, "expr: non-numeric argument\n");
exit (2);
}
r = make_integer (a->u.i - b->u.i);
free_value (a);
free_value (b);
return r;
}
struct val *
op_times (a, b)
struct val *a, *b;
{
struct val *r;
if (!to_integer (a) || !to_integer (b)) {
fprintf (stderr, "expr: non-numeric argument\n");
exit (2);
}
r = make_integer (a->u.i * b->u.i);
free_value (a);
free_value (b);
return (r);
}
struct val *
op_div (a, b)
struct val *a, *b;
{
struct val *r;
if (!to_integer (a) || !to_integer (b)) {
fprintf (stderr, "expr: non-numeric argument\n");
exit (2);
}
if (b->u.i == 0) {
fprintf (stderr, "expr: division by zero\n");
exit (2);
}
r = make_integer (a->u.i / b->u.i);
free_value (a);
free_value (b);
return r;
}
struct val *
op_rem (a, b)
struct val *a, *b;
{
struct val *r;
if (!to_integer (a) || !to_integer (b)) {
fprintf (stderr, "expr: non-numeric argument\n");
exit (2);
}
if (b->u.i == 0) {
fprintf (stderr, "expr: division by zero\n");
exit (2);
}
r = make_integer (a->u.i % b->u.i);
free_value (a);
free_value (b);
return r;
}
#include <regexp.h>
struct val *
op_colon (a, b)
struct val *a, *b;
{
regexp *rp;
char *newexp;
char *p;
char *q;
newexp = malloc (3 * strlen (b->u.s));
p = b->u.s;
q = newexp;
*q++ = '^';
while (*p) {
if (*p == '\\') {
p++;
if (*p == '(' || *p == ')') {
*q++ = *p++;
} else {
*q++ = '\\';
*q++ = *p++;
}
} else if (*p == '(' || *p == ')') {
*q++ = '\\';
*q++ = *p++;
} else {
*q++ = *p++;
}
}
*q = 0;
if ((rp = regcomp (newexp)) == NULL)
yyerror ("invalid regular expression");
if (regexec (rp, a->u.s)) {
if (rp->startp[1]) {
rp->endp[1][0] = 0;
return (make_str (rp->startp[1]));
} else {
return (make_integer (rp->endp[0] - rp->startp[0]));
}
} else {
return (make_integer (0));
}
}