[apple/shell_cmds.git] / expr / expr.y

%{
/*-
 * Written by Pace Willisson (pace@blitz.com)
 * and placed in the public domain.
 *
 * Largely rewritten by J.T. Conklin (jtc@wimsey.com)
 *
 * $FreeBSD: src/bin/expr/expr.y,v 1.28 2011/07/09 12:20:15 se Exp $
 */

#include <sys/types.h>

#include <ctype.h>
#include <err.h>
#include <errno.h>
#include <inttypes.h>
#include <limits.h>
#include <locale.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <regex.h>
#include <unistd.h>

/*
 * POSIX specifies a specific error code for syntax errors.  We exit
 * with this code for all errors.
 */
#define	ERR_EXIT	2

enum valtype {
	integer, numeric_string, string
} ;

struct val {
	enum valtype type;
	union {
		char *s;
		intmax_t i;
	} u;
} ;

char		**av;
int		nonposix;
struct val	*result;

void		assert_to_integer(struct val *);
void		assert_div(intmax_t, intmax_t);
void		assert_minus(intmax_t, intmax_t, intmax_t);
void		assert_plus(intmax_t, intmax_t, intmax_t);
void		assert_times(intmax_t, intmax_t, intmax_t);
int		compare_vals(struct val *, struct val *);
void		free_value(struct val *);
int		is_integer(const char *);
int		is_string(struct val *);
int		is_zero_or_null(struct val *);
struct val	*make_integer(intmax_t);
struct val	*make_str(const char *);
struct val	*op_and(struct val *, struct val *);
struct val	*op_colon(struct val *, struct val *);
struct val	*op_div(struct val *, struct val *);
struct val	*op_eq(struct val *, struct val *);
struct val	*op_ge(struct val *, struct val *);
struct val	*op_gt(struct val *, struct val *);
struct val	*op_le(struct val *, struct val *);
struct val	*op_lt(struct val *, struct val *);
struct val	*op_minus(struct val *, struct val *);
struct val	*op_ne(struct val *, struct val *);
struct val	*op_or(struct val *, struct val *);
struct val	*op_plus(struct val *, struct val *);
struct val	*op_rem(struct val *, struct val *);
struct val	*op_times(struct val *, struct val *);
int		to_integer(struct val *);
void		to_string(struct val *);
int		yyerror(const char *);
int		yylex(void);
int		yyparse(void);

%}

%union
{
	struct val *val;
}

%left <val> '|'
%left <val> '&'
%left <val> '=' '>' '<' GE LE NE
%left <val> '+' '-'
%left <val> '*' '/' '%'
%left <val> ':'

%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); }
	;

%%

struct val *
make_integer(intmax_t i)
{
	struct val *vp;

	vp = (struct val *)malloc(sizeof(*vp));
	if (vp == NULL)
		errx(ERR_EXIT, "malloc() failed");

	vp->type = integer;
	vp->u.i  = i;
	return (vp);
}

struct val *
make_str(const char *s)
{
	struct val *vp;

	vp = (struct val *)malloc(sizeof(*vp));
	if (vp == NULL || ((vp->u.s = strdup(s)) == NULL))
		errx(ERR_EXIT, "malloc() failed");

	if (is_integer(s))
		vp->type = numeric_string;
	else
		vp->type = string;

	return (vp);
}

void
free_value(struct val *vp)
{
	if (vp->type == string || vp->type == numeric_string)
		free(vp->u.s);
}

int
to_integer(struct val *vp)
{
	intmax_t i;

	/* we can only convert numeric_string to integer, here */
	if (vp->type == numeric_string) {
		errno = 0;
		i  = strtoimax(vp->u.s, (char **)NULL, 10);
		/* just keep as numeric_string, if the conversion fails */
		if (errno != ERANGE) {
			free(vp->u.s);
			vp->u.i = i;
			vp->type = integer;
		}
	}
	return (vp->type == integer);
}

void
assert_to_integer(struct val *vp)
{
	if (vp->type == string)
		errx(ERR_EXIT, "not a decimal number: '%s'", vp->u.s);
	if (!to_integer(vp))
		errx(ERR_EXIT, "operand too large: '%s'", vp->u.s);
}

void
to_string(struct val *vp)
{
	char *tmp;

	if (vp->type == string || vp->type == numeric_string)
		return;

	/*
	 * log_10(x) ~= 0.3 * log_2(x).  Rounding up gives the number
	 * of digits; add one each for the sign and terminating null
	 * character, respectively.
	 */
#define	NDIGITS(x) (3 * (sizeof(x) * CHAR_BIT) / 10 + 1 + 1 + 1)
	tmp = malloc(NDIGITS(vp->u.i));
	if (tmp == NULL)
		errx(ERR_EXIT, "malloc() failed");

	sprintf(tmp, "%jd", vp->u.i);
	vp->type = string;
	vp->u.s  = tmp;
}

int
is_integer(const char *s)
{
	if (nonposix) {
		if (*s == '\0')
			return (1);
		while (isspace((unsigned char)*s))
			s++;
	}
	if (*s == '-' || (nonposix && *s == '+'))
		s++;
	if (*s == '\0')
		return (0);
	while (isdigit((unsigned char)*s))
		s++;
	return (*s == '\0');
}

int
is_string(struct val *vp)
{
	/* only TRUE if this string is not a valid integer */
	return (vp->type == string);
}

int
yylex(void)
{
	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(struct val *vp)
{
	if (vp->type == integer)
		return (vp->u.i == 0);

	return (*vp->u.s == 0 || (to_integer(vp) && vp->u.i == 0));
}

int
main(int argc, char *argv[])
{
#ifndef __APPLE__
	int c;
#endif

	setlocale(LC_ALL, "");
#ifdef __APPLE__
	av = argv + 1;
	if (*av && !strcmp(*av, "--"))
		av++;
#else
	if (getenv("EXPR_COMPAT") != NULL
	    || check_utility_compat("expr")) {
		av = argv + 1;
		nonposix = 1;
	} else {
		while ((c = getopt(argc, argv, "e")) != -1) {
			switch (c) {
			case 'e':
				nonposix = 1;
				break;
			default:
				errx(ERR_EXIT,
				    "usage: expr [-e] expression\n");
			}
		}
		av = argv + optind;
	}
#endif

	yyparse();

#ifdef __APPLE__
	if (to_integer(result))
#else
	if (result->type == integer)
#endif
		printf("%jd\n", result->u.i);
	else
		printf("%s\n", result->u.s);

	return (is_zero_or_null(result));
}

int
yyerror(const char *s __unused)
{
	errx(ERR_EXIT, "syntax error");
}

struct val *
op_or(struct val *a, struct val *b)
{
	if (!is_zero_or_null(a)) {
		free_value(b);
		return (a);
	}
	free_value(a);
	if (!is_zero_or_null(b))
		return (b);
	free_value(b);
	return (make_integer((intmax_t)0));
}

struct val *
op_and(struct val *a, struct val *b)
{
	if (is_zero_or_null(a) || is_zero_or_null(b)) {
		free_value(a);
		free_value(b);
		return (make_integer((intmax_t)0));
	} else {
		free_value(b);
		return (a);
	}
}

int
compare_vals(struct val *a, struct val *b)
{
	int r;

	if (is_string(a) || is_string(b)) {
		to_string(a);
		to_string(b);
		r = strcoll(a->u.s, b->u.s);
	} else {
		assert_to_integer(a);
		assert_to_integer(b);
		if (a->u.i > b->u.i)
			r = 1;
		else if (a->u.i < b->u.i)
			r = -1;
		else
			r = 0;
	}

	free_value(a);
	free_value(b);
	return (r);
}

struct val *
op_eq(struct val *a, struct val *b)
{
	return (make_integer((intmax_t)(compare_vals(a, b) == 0)));
}

struct val *
op_gt(struct val *a, struct val *b)
{
	return (make_integer((intmax_t)(compare_vals(a, b) > 0)));
}

struct val *
op_lt(struct val *a, struct val *b)
{
	return (make_integer((intmax_t)(compare_vals(a, b) < 0)));
}

struct val *
op_ge(struct val *a, struct val *b)
{
	return (make_integer((intmax_t)(compare_vals(a, b) >= 0)));
}

struct val *
op_le(struct val *a, struct val *b)
{
	return (make_integer((intmax_t)(compare_vals(a, b) <= 0)));
}

struct val *
op_ne(struct val *a, struct val *b)
{
	return (make_integer((intmax_t)(compare_vals(a, b) != 0)));
}

void
assert_plus(intmax_t a, intmax_t b, intmax_t r)
{
	/*
	 * sum of two positive numbers must be positive,
	 * sum of two negative numbers must be negative
	 */
	if ((a > 0 && b > 0 && r <= 0) ||
	    (a < 0 && b < 0 && r >= 0))
		errx(ERR_EXIT, "overflow");
}

struct val *
op_plus(struct val *a, struct val *b)
{
	struct val *r;

	assert_to_integer(a);
	assert_to_integer(b);
	r = make_integer(a->u.i + b->u.i);
	assert_plus(a->u.i, b->u.i, r->u.i);

	free_value(a);
	free_value(b);
	return (r);
}

void
assert_minus(intmax_t a, intmax_t b, intmax_t r)
{
	/* special case subtraction of INTMAX_MIN */
	if (b == INTMAX_MIN && a < 0)
		errx(ERR_EXIT, "overflow");
	/* check addition of negative subtrahend */
	assert_plus(a, -b, r);
}

struct val *
op_minus(struct val *a, struct val *b)
{
	struct val *r;

	assert_to_integer(a);
	assert_to_integer(b);
	r = make_integer(a->u.i - b->u.i);
	assert_minus(a->u.i, b->u.i, r->u.i);

	free_value(a);
	free_value(b);
	return (r);
}

void
assert_times(intmax_t a, intmax_t b, intmax_t r)
{
	/*
	 * if first operand is 0, no overflow is possible,
	 * else result of division test must match second operand
	 */
	if (a != 0 && r / a != b)
		errx(ERR_EXIT, "overflow");
}

struct val *
op_times(struct val *a, struct val *b)
{
	struct val *r;

	assert_to_integer(a);
	assert_to_integer(b);
	r = make_integer(a->u.i * b->u.i);
	assert_times(a->u.i, b->u.i, r->u.i);

	free_value(a);
	free_value(b);
	return (r);
}

void
assert_div(intmax_t a, intmax_t b)
{
	if (b == 0)
		errx(ERR_EXIT, "division by zero");
	/* only INTMAX_MIN / -1 causes overflow */
	if (a == INTMAX_MIN && b == -1)
		errx(ERR_EXIT, "overflow");
}

struct val *
op_div(struct val *a, struct val *b)
{
	struct val *r;

	assert_to_integer(a);
	assert_to_integer(b);
	/* assert based on operands only, not on result */
	assert_div(a->u.i, b->u.i);
	r = make_integer(a->u.i / b->u.i);

	free_value(a);
	free_value(b);
	return (r);
}

struct val *
op_rem(struct val *a, struct val *b)
{
	struct val *r;

	assert_to_integer(a);
	assert_to_integer(b);
	/* pass a=1 to only check for div by zero */
	assert_div(1, b->u.i);
	r = make_integer(a->u.i % b->u.i);

	free_value(a);
	free_value(b);
	return (r);
}

struct val *
op_colon(struct val *a, struct val *b)
{
	regex_t rp;
	regmatch_t rm[2];
	char errbuf[256];
	int eval;
	struct val *v;

	/* coerce both arguments to strings */
	to_string(a);
	to_string(b);

	/* compile regular expression */
	if ((eval = regcomp(&rp, b->u.s, 0)) != 0) {
		regerror(eval, &rp, errbuf, sizeof(errbuf));
		errx(ERR_EXIT, "%s", errbuf);
	}

	/* compare string against pattern */
	/* remember that patterns are anchored to the beginning of the line */
	if (regexec(&rp, a->u.s, (size_t)2, rm, 0) == 0 && rm[0].rm_so == 0)
		if (rm[1].rm_so >= 0) {
			*(a->u.s + rm[1].rm_eo) = '\0';
			v = make_str(a->u.s + rm[1].rm_so);
#ifdef __APPLE__
			v->type = string; /* 8319378 */
#endif

		} else
			v = make_integer((intmax_t)(rm[0].rm_eo - rm[0].rm_so));
	else
		if (rp.re_nsub == 0)
			v = make_integer((intmax_t)0);
		else
			v = make_str("");

	/* free arguments and pattern buffer */
	free_value(a);
	free_value(b);
	regfree(&rp);

	return (v);
}
Commit	Line	Data
1e9ba8f2 A	1	%{
	2	/*-
	3	* Written by Pace Willisson (pace@blitz.com)
	4	* and placed in the public domain.
	5	*
	6	* Largely rewritten by J.T. Conklin (jtc@wimsey.com)
	7	*
	8	* $FreeBSD: src/bin/expr/expr.y,v 1.28 2011/07/09 12:20:15 se Exp $
	9	*/
	10
	11	#include <sys/types.h>
	12
	13	#include <ctype.h>
	14	#include <err.h>
	15	#include <errno.h>
	16	#include <inttypes.h>
	17	#include <limits.h>
	18	#include <locale.h>
	19	#include <stdio.h>
	20	#include <stdlib.h>
	21	#include <string.h>
	22	#include <regex.h>
	23	#include <unistd.h>
	24
	25	/*
	26	* POSIX specifies a specific error code for syntax errors. We exit
	27	* with this code for all errors.
	28	*/
	29	#define ERR_EXIT 2
	30
	31	enum valtype {
	32	integer, numeric_string, string
	33	} ;
	34
	35	struct val {
	36	enum valtype type;
	37	union {
	38	char *s;
	39	intmax_t i;
	40	} u;
	41	} ;
	42
	43	char **av;
	44	int nonposix;
	45	struct val *result;
	46
	47	void assert_to_integer(struct val *);
	48	void assert_div(intmax_t, intmax_t);
	49	void assert_minus(intmax_t, intmax_t, intmax_t);
	50	void assert_plus(intmax_t, intmax_t, intmax_t);
	51	void assert_times(intmax_t, intmax_t, intmax_t);
	52	int compare_vals(struct val , struct val );
	53	void free_value(struct val *);
	54	int is_integer(const char *);
	55	int is_string(struct val *);
	56	int is_zero_or_null(struct val *);
	57	struct val *make_integer(intmax_t);
	58	struct val make_str(const char );
	59	struct val op_and(struct val , struct val *);
	60	struct val op_colon(struct val , struct val *);
	61	struct val op_div(struct val , struct val *);
	62	struct val op_eq(struct val , struct val *);
	63	struct val op_ge(struct val , struct val *);
	64	struct val op_gt(struct val , struct val *);
65	struct val op_le(struct val , struct val *);
66	struct val op_lt(struct val , struct val *);
67	struct val op_minus(struct val , struct val *);
68	struct val op_ne(struct val , struct val *);
69	struct val op_or(struct val , struct val *);
70	struct val op_plus(struct val , struct val *);
71	struct val op_rem(struct val , struct val *);
72	struct val op_times(struct val , struct val *);
73	int to_integer(struct val *);
74	void to_string(struct val *);
75	int yyerror(const char *);
76	int yylex(void);
77	int yyparse(void);
78
79	%}
80
81	%union
82	{
83	struct val *val;
84	}
85
86	%left <val> '\|'
87	%left <val> '&'
88	%left <val> '=' '>' '<' GE LE NE
89	%left <val> '+' '-'
90	%left <val> '*' '/' '%'
91	%left <val> ':'
92
93	%token <val> TOKEN
94	%type <val> start expr
95
96	%%
97
98	start: expr { result = $$; }
99
100	expr: TOKEN
101	\| '(' expr ')' { $$ = $2; }
102	\| expr '\|' expr { $$ = op_or($1, $3); }
103	\| expr '&' expr { $$ = op_and($1, $3); }
104	\| expr '=' expr { $$ = op_eq($1, $3); }
105	\| expr '>' expr { $$ = op_gt($1, $3); }
106	\| expr '<' expr { $$ = op_lt($1, $3); }
107	\| expr GE expr { $$ = op_ge($1, $3); }
108	\| expr LE expr { $$ = op_le($1, $3); }
109	\| expr NE expr { $$ = op_ne($1, $3); }
110	\| expr '+' expr { $$ = op_plus($1, $3); }
111	\| expr '-' expr { $$ = op_minus($1, $3); }
112	\| expr '*' expr { $$ = op_times($1, $3); }
113	\| expr '/' expr { $$ = op_div($1, $3); }
114	\| expr '%' expr { $$ = op_rem($1, $3); }
115	\| expr ':' expr { $$ = op_colon($1, $3); }
116	;
117
118	%%
119
120	struct val *
121	make_integer(intmax_t i)
122	{
123	struct val *vp;
124
125	vp = (struct val )malloc(sizeof(vp));
126	if (vp == NULL)
127	errx(ERR_EXIT, "malloc() failed");
128
129	vp->type = integer;
130	vp->u.i = i;
131	return (vp);
132	}
133
134	struct val *
135	make_str(const char *s)
136	{
137	struct val *vp;
138
139	vp = (struct val )malloc(sizeof(vp));
140	if (vp == NULL \|\| ((vp->u.s = strdup(s)) == NULL))
141	errx(ERR_EXIT, "malloc() failed");
142
143	if (is_integer(s))
144	vp->type = numeric_string;
145	else
146	vp->type = string;
147
148	return (vp);
149	}
150
151	void
152	free_value(struct val *vp)
153	{
154	if (vp->type == string \|\| vp->type == numeric_string)
155	free(vp->u.s);
156	}
157
158	int
159	to_integer(struct val *vp)
160	{
161	intmax_t i;
162
163	/* we can only convert numeric_string to integer, here */
164	if (vp->type == numeric_string) {
165	errno = 0;
166	i = strtoimax(vp->u.s, (char **)NULL, 10);
167	/* just keep as numeric_string, if the conversion fails */
168	if (errno != ERANGE) {
169	free(vp->u.s);
170	vp->u.i = i;
171	vp->type = integer;
172	}
173	}
174	return (vp->type == integer);
175	}
176
177	void
178	assert_to_integer(struct val *vp)
179	{
180	if (vp->type == string)
181	errx(ERR_EXIT, "not a decimal number: '%s'", vp->u.s);
182	if (!to_integer(vp))
183	errx(ERR_EXIT, "operand too large: '%s'", vp->u.s);
184	}
185
186	void
187	to_string(struct val *vp)
188	{
189	char *tmp;
190
191	if (vp->type == string \|\| vp->type == numeric_string)
192	return;
193
194	/*
195	* log_10(x) ~= 0.3 * log_2(x). Rounding up gives the number
196	* of digits; add one each for the sign and terminating null
197	* character, respectively.
198	*/
199	#define NDIGITS(x) (3 * (sizeof(x) * CHAR_BIT) / 10 + 1 + 1 + 1)
200	tmp = malloc(NDIGITS(vp->u.i));
201	if (tmp == NULL)
202	errx(ERR_EXIT, "malloc() failed");
203
204	sprintf(tmp, "%jd", vp->u.i);
205	vp->type = string;
206	vp->u.s = tmp;
207	}
208
209	int
210	is_integer(const char *s)
211	{
212	if (nonposix) {
213	if (*s == '\0')
214	return (1);
215	while (isspace((unsigned char)*s))
216	s++;
217	}
218	if (s == '-' \|\| (nonposix && s == '+'))
219	s++;
220	if (*s == '\0')
221	return (0);
222	while (isdigit((unsigned char)*s))
223	s++;
224	return (*s == '\0');
225	}
226
227	int
228	is_string(struct val *vp)
229	{
230	/* only TRUE if this string is not a valid integer */
231	return (vp->type == string);
232	}
233
234	int
235	yylex(void)
236	{
237	char *p;
238
239	if (*av == NULL)
240	return (0);
241
242	p = *av++;
243
244	if (strlen(p) == 1) {
245	if (strchr("\|&=<>+-/%:()", p))
246	return (*p);
247	} else if (strlen(p) == 2 && p[1] == '=') {
248	switch (*p) {
249	case '>': return (GE);
250	case '<': return (LE);
251	case '!': return (NE);
252	}
253	}
254
255	yylval.val = make_str(p);
256	return (TOKEN);
257	}
258
259	int
260	is_zero_or_null(struct val *vp)
261	{
262	if (vp->type == integer)
263	return (vp->u.i == 0);
264
265	return (*vp->u.s == 0 \|\| (to_integer(vp) && vp->u.i == 0));
266	}
267
268	int
269	main(int argc, char *argv[])
270	{
271	#ifndef __APPLE__
272	int c;
273	#endif
274
275	setlocale(LC_ALL, "");
276	#ifdef __APPLE__
277	av = argv + 1;
278	if (av && !strcmp(av, "--"))
279	av++;
280	#else
281	if (getenv("EXPR_COMPAT") != NULL
282	\|\| check_utility_compat("expr")) {
283	av = argv + 1;
284	nonposix = 1;
285	} else {
286	while ((c = getopt(argc, argv, "e")) != -1) {
287	switch (c) {
288	case 'e':
289	nonposix = 1;
290	break;
291	default:
292	errx(ERR_EXIT,
293	"usage: expr [-e] expression\n");
294	}
295	}
296	av = argv + optind;
297	}
298	#endif
299
300	yyparse();
301
302	#ifdef __APPLE__
303	if (to_integer(result))
304	#else
305	if (result->type == integer)
306	#endif
307	printf("%jd\n", result->u.i);
308	else
309	printf("%s\n", result->u.s);
310
311	return (is_zero_or_null(result));
312	}
313
314	int
315	yyerror(const char *s __unused)
316	{
317	errx(ERR_EXIT, "syntax error");
318	}
319
320	struct val *
321	op_or(struct val a, struct val b)
322	{
323	if (!is_zero_or_null(a)) {
324	free_value(b);
325	return (a);
326	}
327	free_value(a);
328	if (!is_zero_or_null(b))
329	return (b);
330	free_value(b);
331	return (make_integer((intmax_t)0));
332	}
333
334	struct val *
335	op_and(struct val a, struct val b)
336	{
337	if (is_zero_or_null(a) \|\| is_zero_or_null(b)) {
338	free_value(a);
339	free_value(b);
340	return (make_integer((intmax_t)0));
341	} else {
342	free_value(b);
343	return (a);
344	}
345	}
346
347	int
348	compare_vals(struct val a, struct val b)
349	{
350	int r;
351
352	if (is_string(a) \|\| is_string(b)) {
353	to_string(a);
354	to_string(b);
355	r = strcoll(a->u.s, b->u.s);
356	} else {
357	assert_to_integer(a);
358	assert_to_integer(b);
359	if (a->u.i > b->u.i)
360	r = 1;
361	else if (a->u.i < b->u.i)
362	r = -1;
363	else
364	r = 0;
365	}
366
367	free_value(a);
368	free_value(b);
369	return (r);
370	}
371
372	struct val *
373	op_eq(struct val a, struct val b)
374	{
375	return (make_integer((intmax_t)(compare_vals(a, b) == 0)));
376	}
377
378	struct val *
379	op_gt(struct val a, struct val b)
380	{
381	return (make_integer((intmax_t)(compare_vals(a, b) > 0)));
382	}
383
384	struct val *
385	op_lt(struct val a, struct val b)
386	{
387	return (make_integer((intmax_t)(compare_vals(a, b) < 0)));
388	}
389
390	struct val *
391	op_ge(struct val a, struct val b)
392	{
393	return (make_integer((intmax_t)(compare_vals(a, b) >= 0)));
394	}
395
396	struct val *
397	op_le(struct val a, struct val b)
398	{
399	return (make_integer((intmax_t)(compare_vals(a, b) <= 0)));
400	}
401
402	struct val *
403	op_ne(struct val a, struct val b)
404	{
405	return (make_integer((intmax_t)(compare_vals(a, b) != 0)));
406	}
407
408	void
409	assert_plus(intmax_t a, intmax_t b, intmax_t r)
410	{
411	/*
412	* sum of two positive numbers must be positive,
413	* sum of two negative numbers must be negative
414	*/
415	if ((a > 0 && b > 0 && r <= 0) \|\|
416	(a < 0 && b < 0 && r >= 0))
417	errx(ERR_EXIT, "overflow");
418	}
419
420	struct val *
421	op_plus(struct val a, struct val b)
422	{
423	struct val *r;
424
425	assert_to_integer(a);
426	assert_to_integer(b);
427	r = make_integer(a->u.i + b->u.i);
428	assert_plus(a->u.i, b->u.i, r->u.i);
429
430	free_value(a);
431	free_value(b);
432	return (r);
433	}
434
435	void
436	assert_minus(intmax_t a, intmax_t b, intmax_t r)
437	{
438	/* special case subtraction of INTMAX_MIN */
439	if (b == INTMAX_MIN && a < 0)
440	errx(ERR_EXIT, "overflow");
441	/* check addition of negative subtrahend */
442	assert_plus(a, -b, r);
443	}
444
445	struct val *
446	op_minus(struct val a, struct val b)
447	{
448	struct val *r;
449
450	assert_to_integer(a);
451	assert_to_integer(b);
452	r = make_integer(a->u.i - b->u.i);
453	assert_minus(a->u.i, b->u.i, r->u.i);
454
455	free_value(a);
456	free_value(b);
457	return (r);
458	}
459
460	void
461	assert_times(intmax_t a, intmax_t b, intmax_t r)
462	{
463	/*
464	* if first operand is 0, no overflow is possible,
465	* else result of division test must match second operand
466	*/
467	if (a != 0 && r / a != b)
468	errx(ERR_EXIT, "overflow");
469	}
470
471	struct val *
472	op_times(struct val a, struct val b)
473	{
474	struct val *r;
475
476	assert_to_integer(a);
477	assert_to_integer(b);
478	r = make_integer(a->u.i * b->u.i);
479	assert_times(a->u.i, b->u.i, r->u.i);
480
481	free_value(a);
482	free_value(b);
483	return (r);
484	}
485
486	void
487	assert_div(intmax_t a, intmax_t b)
488	{
489	if (b == 0)
490	errx(ERR_EXIT, "division by zero");
491	/* only INTMAX_MIN / -1 causes overflow */
492	if (a == INTMAX_MIN && b == -1)
493	errx(ERR_EXIT, "overflow");
494	}
495
496	struct val *
497	op_div(struct val a, struct val b)
498	{
499	struct val *r;
500
501	assert_to_integer(a);
502	assert_to_integer(b);
503	/* assert based on operands only, not on result */
504	assert_div(a->u.i, b->u.i);
505	r = make_integer(a->u.i / b->u.i);
506
507	free_value(a);
508	free_value(b);
509	return (r);
510	}
511
512	struct val *
513	op_rem(struct val a, struct val b)
514	{
515	struct val *r;
516
517	assert_to_integer(a);
518	assert_to_integer(b);
519	/* pass a=1 to only check for div by zero */
520	assert_div(1, b->u.i);
521	r = make_integer(a->u.i % b->u.i);
522
523	free_value(a);
524	free_value(b);
525	return (r);
526	}
527
528	struct val *
529	op_colon(struct val a, struct val b)
530	{
531	regex_t rp;
532	regmatch_t rm[2];
533	char errbuf[256];
534	int eval;
535	struct val *v;
536
537	/* coerce both arguments to strings */
538	to_string(a);
539	to_string(b);
540
541	/* compile regular expression */
542	if ((eval = regcomp(&rp, b->u.s, 0)) != 0) {
543	regerror(eval, &rp, errbuf, sizeof(errbuf));
544	errx(ERR_EXIT, "%s", errbuf);
545	}
546
547	/* compare string against pattern */
548	/* remember that patterns are anchored to the beginning of the line */
549	if (regexec(&rp, a->u.s, (size_t)2, rm, 0) == 0 && rm[0].rm_so == 0)
550	if (rm[1].rm_so >= 0) {
551	*(a->u.s + rm[1].rm_eo) = '\0';
552	v = make_str(a->u.s + rm[1].rm_so);
553	#ifdef __APPLE__
554	v->type = string; /* 8319378 */
555	#endif
556
557	} else
558	v = make_integer((intmax_t)(rm[0].rm_eo - rm[0].rm_so));
559	else
560	if (rp.re_nsub == 0)
561	v = make_integer((intmax_t)0);
562	else
563	v = make_str("");
564
565	/* free arguments and pattern buffer */
566	free_value(a);
567	free_value(b);
568	regfree(&rp);
569
570	return (v);
571	}