src/common/calfunc.c

#ifndef lint
static const char       RCSid[] = "$Id: calfunc.c,v 2.20 2019/03/04 20:34:13 greg Exp $";
#endif
/*
 *  calfunc.c - routines for calcomp using functions.
 *
 *      If VARIABLE is not set, only library functions
 *  can be accessed.
 *
 *  2/19/03     Eliminated conditional compiles in favor of esupport extern.
 */

#include "copyright.h"

#include  <stdio.h>
#include  <string.h>
#include  <errno.h>
#include  <math.h>

#include  "rterror.h"
#include  "calcomp.h"

                                /* bits in argument flag (better be right!) */
#define  AFLAGSIZ       (8*sizeof(unsigned long))
#define  ALISTSIZ       8       /* maximum saved argument list */

typedef struct activation {
    char  *name;                /* function name */
    struct activation  *prev;   /* previous activation */
    double  *ap;                /* argument list */
    unsigned long  an;          /* computed argument flags */
    EPNODE  *fun;               /* argument function */
}  ACTIVATION;          /* an activation record */

static ACTIVATION  *curact = NULL;

static double  libfunc(char *fname, VARDEF *vp);

#ifndef  MAXLIB
#define  MAXLIB         64      /* maximum number of library functions */
#endif

static double  l_if(char *), l_select(char *);
static double  l_min(char *), l_max(char *);
static double  l_rand(char *);
static double  l_floor(char *), l_ceil(char *);
static double  l_sqrt(char *);
static double  l_sin(char *), l_cos(char *), l_tan(char *);
static double  l_asin(char *), l_acos(char *), l_atan(char *), l_atan2(char *);
static double  l_exp(char *), l_log(char *), l_log10(char *);

                        /* functions must be listed alphabetically */
static LIBR  library[MAXLIB] = {
    { "acos", 1, ':', l_acos },
    { "asin", 1, ':', l_asin },
    { "atan", 1, ':', l_atan },
    { "atan2", 2, ':', l_atan2 },
    { "ceil", 1, ':', l_ceil },
    { "cos", 1, ':', l_cos },
    { "exp", 1, ':', l_exp },
    { "floor", 1, ':', l_floor },
    { "if", 3, ':', l_if },
    { "log", 1, ':', l_log },
    { "log10", 1, ':', l_log10 },
    { "max", 1, ':', l_max },
    { "min", 1, ':', l_min },
    { "rand", 1, ':', l_rand },
    { "select", 1, ':', l_select },
    { "sin", 1, ':', l_sin },
    { "sqrt", 1, ':', l_sqrt },
    { "tan", 1, ':', l_tan },
};

static int  libsize = 16;

#define  resolve(ep)    ((ep)->type==VAR?(ep)->v.ln:argf((ep)->v.chan))


int
fundefined(                     /* return # of req'd arguments for function */
        char  *fname
)
{
    LIBR  *lp;
    VARDEF  *vp;

    if ((vp = varlookup(fname)) != NULL && vp->def != NULL
                && vp->def->v.kid->type == FUNC)
        return(nekids(vp->def->v.kid) - 1);
    lp = vp != NULL ? vp->lib : liblookup(fname);
    if (lp == NULL)
        return(0);
    return(lp->nargs);
}


double
funvalue(                       /* return a function value to the user */
        char  *fname,
        int  n,
        double  *a
)
{
    ACTIVATION  act;
    VARDEF  *vp;
    double  rval;
                                        /* push environment */
    act.name = fname;
    act.prev = curact;
    act.ap = a;
    if (n < AFLAGSIZ)
        act.an = (1L<<n)-1;
    else {
        act.an = ~0;
        if (n > AFLAGSIZ)
            wputs("Excess arguments in funvalue()\n");
    }
    act.fun = NULL;
    curact = &act;

    if ((vp = varlookup(fname)) == NULL || vp->def == NULL
                || vp->def->v.kid->type != FUNC)
        rval = libfunc(fname, vp);
    else
        rval = evalue(vp->def->v.kid->sibling);

    curact = act.prev;                  /* pop environment */
    return(rval);
}


void
funset(                         /* set a library function */
        char  *fname,
        int  nargs,
        int  assign,
        double  (*fptr)(char *)
)
{
    int  oldlibsize = libsize;
    char *cp;
    LIBR  *lp;
                                                /* check for context */
    for (cp = fname; *cp; cp++)
        ;
    if (cp == fname)
        return;
    while (cp[-1] == CNTXMARK) {
        *--cp = '\0';
        if (cp == fname) return;
    }
    if ((lp = liblookup(fname)) == NULL) {      /* insert */
        if (libsize >= MAXLIB) {
            eputs("Too many library functons!\n");
            quit(1);
        }
        for (lp = &library[libsize]; lp > library; lp--)
            if (strcmp(lp[-1].fname, fname) > 0)
                lp[0] = lp[-1];
            else
                break;
        libsize++;
    }
    if (fptr == NULL) {                         /* delete */
        while (lp < &library[libsize-1]) {
            lp[0] = lp[1];
            lp++;
        }
        libsize--;
    } else {                                    /* or assign */
        lp[0].fname = fname;            /* string must be static! */
        lp[0].nargs = nargs;
        lp[0].atyp = assign;
        lp[0].f = fptr;
    }
    if (libsize != oldlibsize)
        libupdate(fname);                       /* relink library */
}


int
nargum(void)                    /* return number of available arguments */
{
    int  n;

    if (curact == NULL)
        return(0);
    if (curact->fun == NULL) {
        for (n = 0; (1L<<n) & curact->an; n++)
            ;
        return(n);
    }
    return(nekids(curact->fun) - 1);
}


double
argument(int n)                 /* return nth argument for active function */
{
    ACTIVATION  *actp = curact;
    EPNODE  *ep = NULL;
    double  aval;

    if (!n)                                     /* asking for # arguments? */
        return((double)nargum());

    if (!actp | (--n < 0)) {
        eputs("Bad call to argument!\n");
        quit(1);
    }
    if ((n < AFLAGSIZ) & actp->an >> n)         /* already computed? */
        return(actp->ap[n]);

    if (!actp->fun || !(ep = ekid(actp->fun, n+1))) {
        eputs(actp->name);
        eputs(": too few arguments\n");
        quit(1);
    }
    curact = actp->prev;                        /* previous context */
    aval = evalue(ep);                          /* compute argument */
    curact = actp;                              /* put back calling context */
    if (n < ALISTSIZ) {                         /* save value if room */
        actp->ap[n] = aval;
        actp->an |= 1L<<n;
    }
    return(aval);
}


VARDEF *
argf(int n)                     /* return function def for nth argument */
{
    ACTIVATION  *actp;
    EPNODE  *ep;

    for (actp = curact; actp != NULL; actp = actp->prev) {

        if (n <= 0)
            break;

        if (actp->fun == NULL)
            goto badarg;

        if ((ep = ekid(actp->fun, n)) == NULL) {
            eputs(actp->name);
            eputs(": too few arguments\n");
            quit(1);
        }
        if (ep->type == VAR)
            return(ep->v.ln);                   /* found it */

        if (ep->type != ARG)
            goto badarg;

        n = ep->v.chan;                         /* try previous context */
    }
    eputs("Bad call to argf!\n");
    quit(1);

badarg:
    eputs(actp->name);
    eputs(": argument not a function\n");
    quit(1);
        return NULL; /* pro forma return */
}


char *
argfun(int n)                   /* return function name for nth argument */
{
    return(argf(n)->name);
}


double
efunc(EPNODE *ep)                       /* evaluate a function */
{
    ACTIVATION  act;
    double  alist[ALISTSIZ];
    double  rval;
    VARDEF  *dp;
                                        /* push environment */
    dp = resolve(ep->v.kid);
    act.name = dp->name;
    act.prev = curact;
    act.ap = alist;
    act.an = 0;
    act.fun = ep;
    curact = &act;

    if (dp->def == NULL || dp->def->v.kid->type != FUNC)
        rval = libfunc(act.name, dp);
    else
        rval = evalue(dp->def->v.kid->sibling);
    
    curact = act.prev;                  /* pop environment */
    return(rval);
}


LIBR *
liblookup(char *fname)          /* look up a library function */
{
    int  upper, lower;
    int  cm, i;

    lower = 0;
    upper = cm = libsize;

    while ((i = (lower + upper) >> 1) != cm) {
        cm = strcmp(fname, library[i].fname);
        if (cm > 0)
            lower = i;
        else if (cm < 0)
            upper = i;
        else
            return(&library[i]);
        cm = i;
    }
    return(NULL);
}


/*
 *  The following routines are for internal use:
 */


static double
libfunc(                                /* execute library function */
        char  *fname,
        VARDEF  *vp
)
{
    LIBR  *lp;
    double  d;
    int  lasterrno;

    if (vp != NULL)
        lp = vp->lib;
    else
        lp = liblookup(fname);
    if (lp == NULL) {
        eputs(fname);
        eputs(": undefined function\n");
        quit(1);
    }
    lasterrno = errno;
    errno = 0;
    d = (*lp->f)(lp->fname);
#ifdef  isnan
    if (errno == 0) {
        if (isnan(d))
            errno = EDOM;
        else if (isinf(d))
            errno = ERANGE;
    }
#endif
    if (errno == EDOM || errno == ERANGE) {
        wputs(fname);
        if (errno == EDOM)
                wputs(": domain error\n");
        else if (errno == ERANGE)
                wputs(": range error\n");
        else
                wputs(": error in call\n");
        return(0.0);
    }
    errno = lasterrno;
    return(d);
}


/*
 *  Library functions:
 */


static double
l_if(char *nm)          /* if(cond, then, else) conditional expression */
                        /* cond evaluates true if greater than zero */
{
    if (argument(1) > 0.0)
        return(argument(2));
    else
        return(argument(3));
}


static double
l_select(char *nm)      /* return argument #(A1+1) */
{
        int  n;

        n = (int)(argument(1) + .5);
        if (n == 0)
                return(nargum()-1);
        if (n < 1 || n > nargum()-1) {
                errno = EDOM;
                return(0.0);
        }
        return(argument(n+1));
}


static double
l_max(char *nm)         /* general maximum function */
{
        int  n = nargum();
        int  i = 1;
        int  vmax = argument(1);

        while (i++ < n) {
                double  v = argument(i);
                if (vmax < v)
                        vmax = v;
        }
        return(vmax);
}


static double
l_min(char *nm)         /* general minimum function */
{
        int  n = nargum();
        int  i = 1;
        int  vmin = argument(1);

        while (i++ < n) {
                double  v = argument(i);
                if (vmin > v)
                        vmin = v;
        }
        return(vmin);
}


static double
l_rand(char *nm)                /* random function between 0 and 1 */
{
    double  x;

    x = argument(1);
    x *= 1.0/(1.0 + x*x) + 2.71828182845904;
    x += .785398163397447 - floor(x);
    x = 1e5 / x;
    return(x - floor(x));
}


static double
l_floor(char *nm)               /* return largest integer not greater than arg1 */
{
    return(floor(argument(1)));
}


static double
l_ceil(char *nm)                /* return smallest integer not less than arg1 */
{
    return(ceil(argument(1)));
}


static double
l_sqrt(char *nm)
{
    return(sqrt(argument(1)));
}


static double
l_sin(char *nm)
{
    return(sin(argument(1)));
}


static double
l_cos(char *nm)
{
    return(cos(argument(1)));
}


static double
l_tan(char *nm)
{
    return(tan(argument(1)));
}


static double
l_asin(char *nm)
{
    return(asin(argument(1)));
}


static double
l_acos(char *nm)
{
    return(acos(argument(1)));
}


static double
l_atan(char *nm)
{
    return(atan(argument(1)));
}


static double
l_atan2(char *nm)
{
    return(atan2(argument(1), argument(2)));
}


static double
l_exp(char *nm)
{
    return(exp(argument(1)));
}


static double
l_log(char *nm)
{
    return(log(argument(1)));
}


static double
l_log10(char *nm)
{
    return(log10(argument(1)));
}
Revision:	2.21
Committed:	Mon Jun 10 13:56:52 2019 UTC (4 years, 11 months ago) by greg
Content type:	text/plain
Branch:	MAIN
Changes since 2.20:	+45 -4 lines
Log Message:	Added max() and min() as .cal library functions
#	User	Rev	Content
1	greg	1.1	#ifndef lint
2	greg	2.21	static const char RCSid[] = "$Id: calfunc.c,v 2.20 2019/03/04 20:34:13 greg Exp $";
3	greg	1.1	#endif
4			/*
5			* calfunc.c - routines for calcomp using functions.
6			*
7	greg	2.8	* If VARIABLE is not set, only library functions
8			* can be accessed.
9			*
10			* 2/19/03 Eliminated conditional compiles in favor of esupport extern.
11			*/
12
13	greg	2.9	#include "copyright.h"
14	greg	1.1
15			#include <stdio.h>
16	schorsch	2.11	#include <string.h>
17	greg	1.1	#include <errno.h>
18	greg	2.5	#include <math.h>
19
20	schorsch	2.12	#include "rterror.h"
21	greg	1.1	#include "calcomp.h"
22
23	greg	1.5	/* bits in argument flag (better be right!) */
24			#define AFLAGSIZ (8*sizeof(unsigned long))
25	greg	2.19	#define ALISTSIZ 8 /* maximum saved argument list */
26	greg	1.1
27			typedef struct activation {
28			char name; / function name */
29			struct activation prev; / previous activation */
30			double ap; / argument list */
31			unsigned long an; /* computed argument flags */
32			EPNODE fun; / argument function */
33			} ACTIVATION; /* an activation record */
34
35			static ACTIVATION *curact = NULL;
36
37	schorsch	2.12	static double libfunc(char fname, VARDEF vp);
38	greg	1.1
39	greg	2.8	#ifndef MAXLIB
40	greg	1.1	#define MAXLIB 64 /* maximum number of library functions */
41	greg	2.8	#endif
42	greg	1.1
43	greg	2.21	static double l_if(char ), l_select(char );
44			static double l_min(char ), l_max(char );
45			static double l_rand(char *);
46	greg	2.13	static double l_floor(char ), l_ceil(char );
47			static double l_sqrt(char *);
48			static double l_sin(char ), l_cos(char ), l_tan(char *);
49			static double l_asin(char ), l_acos(char ), l_atan(char ), l_atan2(char );
50			static double l_exp(char ), l_log(char ), l_log10(char *);
51	greg	1.1
52			/* functions must be listed alphabetically */
53			static LIBR library[MAXLIB] = {
54	greg	1.4	{ "acos", 1, ':', l_acos },
55			{ "asin", 1, ':', l_asin },
56			{ "atan", 1, ':', l_atan },
57			{ "atan2", 2, ':', l_atan2 },
58			{ "ceil", 1, ':', l_ceil },
59			{ "cos", 1, ':', l_cos },
60			{ "exp", 1, ':', l_exp },
61			{ "floor", 1, ':', l_floor },
62			{ "if", 3, ':', l_if },
63			{ "log", 1, ':', l_log },
64			{ "log10", 1, ':', l_log10 },
65	greg	2.21	{ "max", 1, ':', l_max },
66			{ "min", 1, ':', l_min },
67	greg	1.4	{ "rand", 1, ':', l_rand },
68			{ "select", 1, ':', l_select },
69			{ "sin", 1, ':', l_sin },
70			{ "sqrt", 1, ':', l_sqrt },
71			{ "tan", 1, ':', l_tan },
72	greg	1.1	};
73
74			static int libsize = 16;
75
76			#define resolve(ep) ((ep)->type==VAR?(ep)->v.ln:argf((ep)->v.chan))
77
78
79			int
80	greg	2.21	fundefined( /* return # of req'd arguments for function */
81	greg	2.16	char *fname
82			)
83	greg	1.1	{
84	greg	2.16	LIBR *lp;
85			VARDEF *vp;
86	greg	1.1
87	greg	2.7	if ((vp = varlookup(fname)) != NULL && vp->def != NULL
88			&& vp->def->v.kid->type == FUNC)
89	greg	1.1	return(nekids(vp->def->v.kid) - 1);
90	greg	2.7	lp = vp != NULL ? vp->lib : liblookup(fname);
91			if (lp == NULL)
92			return(0);
93			return(lp->nargs);
94	greg	1.1	}
95
96
97			double
98	greg	2.16	funvalue( /* return a function value to the user */
99			char *fname,
100			int n,
101			double *a
102			)
103	greg	1.1	{
104			ACTIVATION act;
105	greg	2.16	VARDEF *vp;
106	greg	1.1	double rval;
107			/* push environment */
108			act.name = fname;
109			act.prev = curact;
110			act.ap = a;
111	greg	2.19	if (n < AFLAGSIZ)
112			act.an = (1L<<n)-1;
113			else {
114	greg	1.5	act.an = ~0;
115	greg	2.19	if (n > AFLAGSIZ)
116			wputs("Excess arguments in funvalue()\n");
117			}
118	greg	1.1	act.fun = NULL;
119			curact = &act;
120
121			if ((vp = varlookup(fname)) == NULL \|\| vp->def == NULL
122			\|\| vp->def->v.kid->type != FUNC)
123			rval = libfunc(fname, vp);
124			else
125			rval = evalue(vp->def->v.kid->sibling);
126
127			curact = act.prev; /* pop environment */
128			return(rval);
129			}
130
131
132	greg	2.8	void
133	greg	2.16	funset( /* set a library function */
134			char *fname,
135			int nargs,
136			int assign,
137			double (fptr)(char )
138			)
139	greg	1.1	{
140	greg	2.6	int oldlibsize = libsize;
141	greg	2.8	char *cp;
142	greg	2.16	LIBR *lp;
143	greg	2.8	/* check for context */
144			for (cp = fname; *cp; cp++)
145			;
146			if (cp == fname)
147			return;
148	greg	2.21	while (cp[-1] == CNTXMARK) {
149	greg	2.8	*--cp = '\0';
150	greg	2.21	if (cp == fname) return;
151			}
152	greg	2.2	if ((lp = liblookup(fname)) == NULL) { /* insert */
153	greg	1.1	if (libsize >= MAXLIB) {
154			eputs("Too many library functons!\n");
155			quit(1);
156			}
157			for (lp = &library[libsize]; lp > library; lp--)
158	greg	2.17	if (strcmp(lp[-1].fname, fname) > 0)
159			lp[0] = lp[-1];
160			else
161	greg	1.1	break;
162			libsize++;
163			}
164	greg	2.2	if (fptr == NULL) { /* delete */
165			while (lp < &library[libsize-1]) {
166	greg	2.17	lp[0] = lp[1];
167	greg	2.2	lp++;
168			}
169			libsize--;
170			} else { /* or assign */
171			lp[0].fname = fname; /* string must be static! */
172			lp[0].nargs = nargs;
173			lp[0].atyp = assign;
174			lp[0].f = fptr;
175			}
176	greg	2.6	if (libsize != oldlibsize)
177			libupdate(fname); /* relink library */
178	greg	1.1	}
179
180
181			int
182	greg	2.16	nargum(void) /* return number of available arguments */
183	greg	1.1	{
184	greg	2.16	int n;
185	greg	1.1
186			if (curact == NULL)
187			return(0);
188			if (curact->fun == NULL) {
189			for (n = 0; (1L<<n) & curact->an; n++)
190			;
191			return(n);
192			}
193			return(nekids(curact->fun) - 1);
194			}
195
196
197			double
198	greg	2.16	argument(int n) /* return nth argument for active function */
199	greg	1.1	{
200	greg	2.16	ACTIVATION *actp = curact;
201			EPNODE *ep = NULL;
202	greg	1.1	double aval;
203
204	greg	2.21	if (!n) /* asking for # arguments? */
205			return((double)nargum());
206
207	greg	2.19	if (!actp \| (--n < 0)) {
208	greg	1.1	eputs("Bad call to argument!\n");
209			quit(1);
210			}
211	greg	2.20	if ((n < AFLAGSIZ) & actp->an >> n) /* already computed? */
212	greg	1.1	return(actp->ap[n]);
213
214	greg	2.19	if (!actp->fun \|\| !(ep = ekid(actp->fun, n+1))) {
215	greg	1.1	eputs(actp->name);
216			eputs(": too few arguments\n");
217			quit(1);
218			}
219	greg	2.19	curact = actp->prev; /* previous context */
220	greg	1.1	aval = evalue(ep); /* compute argument */
221	greg	2.20	curact = actp; /* put back calling context */
222			if (n < ALISTSIZ) { /* save value if room */
223	greg	1.1	actp->ap[n] = aval;
224			actp->an \|= 1L<<n;
225			}
226			return(aval);
227			}
228
229
230			VARDEF *
231	greg	2.16	argf(int n) /* return function def for nth argument */
232	greg	1.1	{
233	greg	2.16	ACTIVATION *actp;
234			EPNODE *ep;
235	greg	1.1
236			for (actp = curact; actp != NULL; actp = actp->prev) {
237
238			if (n <= 0)
239			break;
240
241			if (actp->fun == NULL)
242			goto badarg;
243
244			if ((ep = ekid(actp->fun, n)) == NULL) {
245			eputs(actp->name);
246			eputs(": too few arguments\n");
247			quit(1);
248			}
249			if (ep->type == VAR)
250			return(ep->v.ln); /* found it */
251
252			if (ep->type != ARG)
253			goto badarg;
254
255			n = ep->v.chan; /* try previous context */
256			}
257			eputs("Bad call to argf!\n");
258			quit(1);
259
260			badarg:
261			eputs(actp->name);
262			eputs(": argument not a function\n");
263			quit(1);
264	schorsch	2.11	return NULL; /* pro forma return */
265	greg	1.1	}
266
267
268			char *
269	greg	2.16	argfun(int n) /* return function name for nth argument */
270	greg	1.1	{
271			return(argf(n)->name);
272			}
273
274
275			double
276	greg	2.16	efunc(EPNODE ep) / evaluate a function */
277	greg	1.1	{
278			ACTIVATION act;
279			double alist[ALISTSIZ];
280			double rval;
281	greg	2.16	VARDEF *dp;
282	greg	1.1	/* push environment */
283			dp = resolve(ep->v.kid);
284			act.name = dp->name;
285			act.prev = curact;
286			act.ap = alist;
287			act.an = 0;
288			act.fun = ep;
289			curact = &act;
290
291			if (dp->def == NULL \|\| dp->def->v.kid->type != FUNC)
292			rval = libfunc(act.name, dp);
293			else
294			rval = evalue(dp->def->v.kid->sibling);
295
296			curact = act.prev; /* pop environment */
297			return(rval);
298			}
299
300
301			LIBR *
302	greg	2.16	liblookup(char fname) / look up a library function */
303	greg	1.1	{
304			int upper, lower;
305	greg	2.16	int cm, i;
306	greg	1.1
307			lower = 0;
308			upper = cm = libsize;
309
310			while ((i = (lower + upper) >> 1) != cm) {
311			cm = strcmp(fname, library[i].fname);
312			if (cm > 0)
313			lower = i;
314			else if (cm < 0)
315			upper = i;
316			else
317			return(&library[i]);
318			cm = i;
319			}
320			return(NULL);
321			}
322
323
324			/*
325			* The following routines are for internal use:
326			*/
327
328
329			static double
330	greg	2.16	libfunc( /* execute library function */
331			char *fname,
332			VARDEF *vp
333			)
334	greg	1.1	{
335	greg	2.16	LIBR *lp;
336	greg	1.1	double d;
337			int lasterrno;
338
339	greg	2.3	if (vp != NULL)
340			lp = vp->lib;
341			else
342			lp = liblookup(fname);
343			if (lp == NULL) {
344	greg	1.1	eputs(fname);
345			eputs(": undefined function\n");
346			quit(1);
347			}
348			lasterrno = errno;
349			errno = 0;
350	greg	2.3	d = (*lp->f)(lp->fname);
351	greg	2.15	#ifdef isnan
352	greg	2.18	if (errno == 0) {
353	greg	1.9	if (isnan(d))
354			errno = EDOM;
355			else if (isinf(d))
356			errno = ERANGE;
357	greg	2.18	}
358	greg	1.1	#endif
359	greg	2.10	if (errno == EDOM \|\| errno == ERANGE) {
360	greg	1.1	wputs(fname);
361	greg	1.8	if (errno == EDOM)
362			wputs(": domain error\n");
363			else if (errno == ERANGE)
364			wputs(": range error\n");
365			else
366			wputs(": error in call\n");
367	greg	1.1	return(0.0);
368			}
369			errno = lasterrno;
370			return(d);
371			}
372
373
374			/*
375			* Library functions:
376			*/
377
378
379			static double
380	greg	2.13	l_if(char nm) / if(cond, then, else) conditional expression */
381	greg	1.1	/* cond evaluates true if greater than zero */
382			{
383			if (argument(1) > 0.0)
384			return(argument(2));
385			else
386			return(argument(3));
387			}
388
389
390			static double
391	greg	2.13	l_select(char nm) / return argument #(A1+1) */
392	greg	1.1	{
393	greg	2.16	int n;
394	greg	1.1
395	schorsch	2.11	n = (int)(argument(1) + .5);
396	greg	1.1	if (n == 0)
397			return(nargum()-1);
398			if (n < 1 \|\| n > nargum()-1) {
399			errno = EDOM;
400			return(0.0);
401			}
402			return(argument(n+1));
403			}
404
405
406			static double
407	greg	2.21	l_max(char nm) / general maximum function */
408			{
409			int n = nargum();
410			int i = 1;
411			int vmax = argument(1);
412
413			while (i++ < n) {
414			double v = argument(i);
415			if (vmax < v)
416			vmax = v;
417			}
418			return(vmax);
419			}
420
421
422			static double
423			l_min(char nm) / general minimum function */
424			{
425			int n = nargum();
426			int i = 1;
427			int vmin = argument(1);
428
429			while (i++ < n) {
430			double v = argument(i);
431			if (vmin > v)
432			vmin = v;
433			}
434			return(vmin);
435			}
436
437
438			static double
439	greg	2.13	l_rand(char nm) / random function between 0 and 1 */
440	greg	1.1	{
441			double x;
442
443			x = argument(1);
444			x = 1.0/(1.0 + xx) + 2.71828182845904;
445			x += .785398163397447 - floor(x);
446			x = 1e5 / x;
447			return(x - floor(x));
448			}
449
450
451			static double
452	greg	2.13	l_floor(char nm) / return largest integer not greater than arg1 */
453	greg	1.1	{
454			return(floor(argument(1)));
455			}
456
457
458			static double
459	greg	2.13	l_ceil(char nm) / return smallest integer not less than arg1 */
460	greg	1.1	{
461			return(ceil(argument(1)));
462			}
463
464
465			static double
466	greg	2.13	l_sqrt(char *nm)
467	greg	1.1	{
468			return(sqrt(argument(1)));
469			}
470
471
472			static double
473	greg	2.13	l_sin(char *nm)
474	greg	1.1	{
475			return(sin(argument(1)));
476			}
477
478
479			static double
480	greg	2.13	l_cos(char *nm)
481	greg	1.1	{
482			return(cos(argument(1)));
483			}
484
485
486			static double
487	greg	2.13	l_tan(char *nm)
488	greg	1.1	{
489			return(tan(argument(1)));
490			}
491
492
493			static double
494	greg	2.13	l_asin(char *nm)
495	greg	1.1	{
496			return(asin(argument(1)));
497			}
498
499
500			static double
501	greg	2.13	l_acos(char *nm)
502	greg	1.1	{
503			return(acos(argument(1)));
504			}
505
506
507			static double
508	greg	2.13	l_atan(char *nm)
509	greg	1.1	{
510			return(atan(argument(1)));
511			}
512
513
514			static double
515	greg	2.13	l_atan2(char *nm)
516	greg	1.1	{
517			return(atan2(argument(1), argument(2)));
518			}
519
520
521			static double
522	greg	2.13	l_exp(char *nm)
523	greg	1.1	{
524			return(exp(argument(1)));
525			}
526
527
528			static double
529	greg	2.13	l_log(char *nm)
530	greg	1.1	{
531			return(log(argument(1)));
532			}
533
534
535			static double
536	greg	2.13	l_log10(char *nm)
537	greg	1.1	{
538			return(log10(argument(1)));
539			}