| 1 |
#ifndef lint
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static const char RCSid[] = "$Id: calexpr.c,v 2.48 2024/02/25 04:41:44 greg Exp $";
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| 3 |
#endif
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/*
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| 5 |
* Compute data values using expression parser
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*
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* 7/1/85 Greg Ward
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| 8 |
*
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* 11/11/85 Made channel input conditional with (INCHAN) compiles.
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| 10 |
*
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* 4/2/86 Added conditional compiles for function definitions (FUNCTION).
|
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*
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* 1/29/87 Made variables conditional (VARIABLE)
|
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*
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* 5/19/88 Added constant subexpression elimination (RCONST)
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*
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* 2/19/03 Eliminated conditional compiles in favor of esupport extern.
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*/
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#include "copyright.h"
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#include <ctype.h>
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#include <errno.h>
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#include <math.h>
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#include <stdlib.h>
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#include "rtmisc.h"
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#include "rtio.h"
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#include "rterror.h"
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#include "calcomp.h"
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#define MAXLINE 256 /* maximum line length */
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#define newnode() (EPNODE *)ecalloc(1, sizeof(EPNODE))
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#define isdecimal(c) (isdigit(c) | ((c) == '.'))
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#define envalue(ep) ((ep)->type==NUM ? (ep)->v.num : evalue(ep))
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static double euminus(EPNODE *), enumber(EPNODE *);
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static double echannel(EPNODE *);
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static double eadd(EPNODE *), esubtr(EPNODE *),
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emult(EPNODE *), edivi(EPNODE *),
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epow(EPNODE *);
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static double ebotch(EPNODE *);
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unsigned int esupport = /* what to support */
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E_VARIABLE | E_FUNCTION ;
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int eofc = 0; /* optional end-of-file character */
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int nextc; /* lookahead character */
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double (*eoper[])(EPNODE *) = { /* expression operations */
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ebotch,
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evariable,
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enumber,
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euminus,
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echannel,
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efunc,
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eargument,
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ebotch,
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ebotch,
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0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
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0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
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emult,
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eadd,
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0,
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esubtr,
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0,
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edivi,
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0,0,0,0,0,0,0,0,0,0,
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ebotch,
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0,0,
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ebotch,
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0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
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0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
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epow,
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};
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static FILE *infp; /* input file pointer */
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static char *linbuf; /* line buffer */
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static char *infile; /* input file name */
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static int lineno; /* input line number */
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static int linepos; /* position in buffer */
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EPNODE *
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eparse( /* parse an expression string */
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char *expr
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)
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{
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EPNODE *ep;
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initstr(expr, NULL, 0);
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curfunc = NULL;
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ep = getE1();
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if (nextc != EOF)
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syntax("unexpected character");
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return(ep);
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}
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double
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eval( /* evaluate an expression string */
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char *expr
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)
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{
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int prev_support = esupport;
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EPNODE *ep;
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double rval;
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esupport &= ~E_RCONST; /* don't bother reducing constant expr */
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ep = eparse(expr);
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esupport = prev_support; /* as you were */
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rval = evalue(ep);
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epfree(ep,1);
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return(rval);
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}
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int
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epcmp( /* compare two expressions for equivalence */
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EPNODE *ep1,
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EPNODE *ep2
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)
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{
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double d;
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if (ep1->type != ep2->type)
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return(1);
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switch (ep1->type) {
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case VAR:
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return(ep1->v.ln != ep2->v.ln);
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case NUM:
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if (ep2->v.num == 0)
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return(ep1->v.num != 0);
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d = ep1->v.num / ep2->v.num;
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return((d > 1.000000000001) | (d < 0.999999999999));
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case CHAN:
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case ARG:
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return(ep1->v.chan != ep2->v.chan);
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case '=':
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case ':':
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return(epcmp(ep1->v.kid->sibling, ep2->v.kid->sibling));
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case CLKT:
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case SYM: /* should never get this one */
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return(0);
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default:
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ep1 = ep1->v.kid;
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ep2 = ep2->v.kid;
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while (ep1 != NULL) {
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if (ep2 == NULL)
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return(1);
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if (epcmp(ep1, ep2))
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return(1);
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ep1 = ep1->sibling;
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ep2 = ep2->sibling;
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}
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return(ep2 != NULL);
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}
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}
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void
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epfree( /* free a parse tree */
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EPNODE *epar,
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int frep
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)
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{
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EPNODE *ep;
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switch (epar->type) {
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case VAR:
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varfree(epar->v.ln);
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break;
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case SYM:
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freestr(epar->v.name);
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break;
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case NUM:
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case CHAN:
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case ARG:
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case CLKT:
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break;
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default:
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if (epar->nkids < 0) {
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ep = epar->v.kid - epar->nkids;
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while (ep > epar->v.kid)
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epfree(--ep, 0);
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efree(ep); /* free array space */
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} else
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while ((ep = epar->v.kid) != NULL) {
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epar->v.kid = ep->sibling;
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epfree(ep, 1);
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}
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break;
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}
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if (frep)
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efree(epar);
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}
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static void
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epflatten( /* flatten hierarchies for '+', '*' */
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EPNODE *epar
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)
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{
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EPNODE *ep;
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if (epar->nkids < 0) /* can't handle array allocations */
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return;
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for (ep = epar->v.kid; ep != NULL; ep = ep->sibling)
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while (ep->type == epar->type && ep->nkids > 0) {
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EPNODE *ep1 = ep->v.kid;
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while (ep1->sibling != NULL)
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ep1 = ep1->sibling;
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ep1->sibling = ep->sibling;
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epar->nkids += ep->nkids - 1;
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ep1 = ep->v.kid;
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*ep = *ep1;
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efree(ep1); /* not epfree()! */
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}
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}
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void
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epoptimize( /* flatten operations, lists -> arrays */
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EPNODE *epar
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)
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{
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EPNODE *ep;
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if ((epar->type == '+') | (epar->type == '*'))
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epflatten(epar); /* flatten associative operations */
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if (epar->nkids) /* do children if any */
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for (ep = epar->v.kid; ep != NULL; ep = ep->sibling)
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epoptimize(ep);
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if (epar->nkids > 4) { /* make list into array if > 4 kids */
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int n = 1;
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epar->v.kid = (EPNODE *)erealloc(epar->v.kid,
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sizeof(EPNODE)*epar->nkids);
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while (n < epar->nkids) {
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ep = epar->v.kid[n-1].sibling;
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epar->v.kid[n] = *ep;
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efree(ep); /* not epfree()! */
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epar->v.kid[n-1].sibling = epar->v.kid + n;
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n++;
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}
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epar->nkids = -n;
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}
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}
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/* the following used to be a switch */
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static double
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enumber(
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EPNODE *ep
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)
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{
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return(ep->v.num);
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}
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static double
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euminus(
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EPNODE *ep
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)
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{
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EPNODE *ep1 = ep->v.kid;
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| 282 |
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return(-evalue(ep1));
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}
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static double
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echannel(
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| 288 |
EPNODE *ep
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)
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| 290 |
{
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| 291 |
return(chanvalue(ep->v.chan));
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}
|
| 293 |
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| 294 |
static double
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| 295 |
eadd(
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| 296 |
EPNODE *ep
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| 297 |
)
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| 298 |
{
|
| 299 |
double sum = 0;
|
| 300 |
EPNODE *ep1 = ep->v.kid;
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| 301 |
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| 302 |
do
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| 303 |
sum += envalue(ep1);
|
| 304 |
while ((ep1 = ep1->sibling) != NULL);
|
| 305 |
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| 306 |
return(sum);
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| 307 |
}
|
| 308 |
|
| 309 |
static double
|
| 310 |
esubtr(
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| 311 |
EPNODE *ep
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| 312 |
)
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| 313 |
{
|
| 314 |
EPNODE *ep1 = ep->v.kid;
|
| 315 |
EPNODE *ep2 = ep1->sibling;
|
| 316 |
|
| 317 |
return(envalue(ep1) - envalue(ep2));
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| 318 |
}
|
| 319 |
|
| 320 |
static double
|
| 321 |
emult(
|
| 322 |
EPNODE *ep
|
| 323 |
)
|
| 324 |
{
|
| 325 |
double prod = 1;
|
| 326 |
EPNODE *ep1 = ep->v.kid;
|
| 327 |
|
| 328 |
do
|
| 329 |
prod *= envalue(ep1);
|
| 330 |
while ((ep1 = ep1->sibling) != NULL);
|
| 331 |
|
| 332 |
return(prod);
|
| 333 |
}
|
| 334 |
|
| 335 |
static double
|
| 336 |
edivi(
|
| 337 |
EPNODE *ep
|
| 338 |
)
|
| 339 |
{
|
| 340 |
EPNODE *ep1 = ep->v.kid;
|
| 341 |
double den = evalue(ep1->sibling);
|
| 342 |
|
| 343 |
if (den == 0.0) {
|
| 344 |
wputs("Division by zero\n");
|
| 345 |
errno = ERANGE;
|
| 346 |
return(0.0);
|
| 347 |
}
|
| 348 |
return(envalue(ep1) / den);
|
| 349 |
}
|
| 350 |
|
| 351 |
static double
|
| 352 |
epow(
|
| 353 |
EPNODE *ep
|
| 354 |
)
|
| 355 |
{
|
| 356 |
EPNODE *ep1 = ep->v.kid;
|
| 357 |
double d;
|
| 358 |
int lasterrno;
|
| 359 |
|
| 360 |
lasterrno = errno;
|
| 361 |
errno = 0;
|
| 362 |
d = pow(evalue(ep1), evalue(ep1->sibling));
|
| 363 |
#ifdef isnan
|
| 364 |
if (errno == 0) {
|
| 365 |
if (isnan(d))
|
| 366 |
errno = EDOM;
|
| 367 |
else if (isinf(d))
|
| 368 |
errno = ERANGE;
|
| 369 |
}
|
| 370 |
#endif
|
| 371 |
if ((errno == EDOM) | (errno == ERANGE)) {
|
| 372 |
wputs("Illegal power\n");
|
| 373 |
return(0.0);
|
| 374 |
}
|
| 375 |
errno = lasterrno;
|
| 376 |
return(d);
|
| 377 |
}
|
| 378 |
|
| 379 |
static double
|
| 380 |
ebotch(
|
| 381 |
EPNODE *ep
|
| 382 |
)
|
| 383 |
{
|
| 384 |
eputs("Bad expression!\n");
|
| 385 |
quit(1);
|
| 386 |
return 0.0; /* pro forma return */
|
| 387 |
}
|
| 388 |
|
| 389 |
|
| 390 |
EPNODE *
|
| 391 |
ekid( /* return pointer to a node's nth kid */
|
| 392 |
EPNODE *ep,
|
| 393 |
int n
|
| 394 |
)
|
| 395 |
{
|
| 396 |
if (ep->nkids < 0) { /* allocated array? */
|
| 397 |
if (n >= -ep->nkids)
|
| 398 |
return(NULL);
|
| 399 |
return(ep->v.kid + n);
|
| 400 |
}
|
| 401 |
ep = ep->v.kid; /* else get from list */
|
| 402 |
while (n-- > 0)
|
| 403 |
if ((ep = ep->sibling) == NULL)
|
| 404 |
break;
|
| 405 |
return(ep);
|
| 406 |
}
|
| 407 |
|
| 408 |
|
| 409 |
void
|
| 410 |
initfile( /* prepare input file */
|
| 411 |
FILE *fp,
|
| 412 |
char *fn,
|
| 413 |
int ln
|
| 414 |
)
|
| 415 |
{
|
| 416 |
static char inpbuf[MAXLINE];
|
| 417 |
|
| 418 |
infp = fp;
|
| 419 |
linbuf = inpbuf;
|
| 420 |
infile = fn;
|
| 421 |
lineno = ln;
|
| 422 |
linepos = 0;
|
| 423 |
inpbuf[0] = '\0';
|
| 424 |
scan();
|
| 425 |
}
|
| 426 |
|
| 427 |
|
| 428 |
void
|
| 429 |
initstr( /* prepare input string */
|
| 430 |
char *s,
|
| 431 |
char *fn,
|
| 432 |
int ln
|
| 433 |
)
|
| 434 |
{
|
| 435 |
infp = NULL;
|
| 436 |
infile = fn;
|
| 437 |
lineno = ln;
|
| 438 |
linbuf = s;
|
| 439 |
linepos = 0;
|
| 440 |
scan();
|
| 441 |
}
|
| 442 |
|
| 443 |
|
| 444 |
void
|
| 445 |
getscanpos( /* return current scan position */
|
| 446 |
char **fnp,
|
| 447 |
int *lnp,
|
| 448 |
char **spp,
|
| 449 |
FILE **fpp
|
| 450 |
)
|
| 451 |
{
|
| 452 |
if (fnp != NULL) *fnp = infile;
|
| 453 |
if (lnp != NULL) *lnp = lineno;
|
| 454 |
if (spp != NULL) *spp = linbuf+linepos;
|
| 455 |
if (fpp != NULL) *fpp = infp;
|
| 456 |
}
|
| 457 |
|
| 458 |
|
| 459 |
int
|
| 460 |
scan(void) /* scan next character, return literal next */
|
| 461 |
{
|
| 462 |
int lnext = 0;
|
| 463 |
|
| 464 |
do {
|
| 465 |
if (linbuf[linepos] == '\0')
|
| 466 |
if (infp == NULL || fgets(linbuf, MAXLINE, infp) == NULL)
|
| 467 |
nextc = EOF;
|
| 468 |
else {
|
| 469 |
nextc = linbuf[0];
|
| 470 |
lineno++;
|
| 471 |
linepos = 1;
|
| 472 |
}
|
| 473 |
else
|
| 474 |
nextc = linbuf[linepos++];
|
| 475 |
if (!lnext)
|
| 476 |
lnext = nextc;
|
| 477 |
if (nextc == eofc) {
|
| 478 |
nextc = EOF;
|
| 479 |
break;
|
| 480 |
}
|
| 481 |
if (nextc == '{') {
|
| 482 |
scan();
|
| 483 |
while (nextc != '}')
|
| 484 |
if (nextc == EOF)
|
| 485 |
syntax("'}' expected");
|
| 486 |
else
|
| 487 |
scan();
|
| 488 |
scan();
|
| 489 |
}
|
| 490 |
} while (isspace(nextc));
|
| 491 |
return(lnext);
|
| 492 |
}
|
| 493 |
|
| 494 |
|
| 495 |
char *
|
| 496 |
long2ascii( /* convert long to ascii */
|
| 497 |
long l
|
| 498 |
)
|
| 499 |
{
|
| 500 |
static char buf[16];
|
| 501 |
char *cp;
|
| 502 |
int neg = 0;
|
| 503 |
|
| 504 |
if (l == 0)
|
| 505 |
return("0");
|
| 506 |
if (l < 0) {
|
| 507 |
l = -l;
|
| 508 |
neg++;
|
| 509 |
}
|
| 510 |
cp = buf + sizeof(buf);
|
| 511 |
*--cp = '\0';
|
| 512 |
while (l) {
|
| 513 |
*--cp = l % 10 + '0';
|
| 514 |
l /= 10;
|
| 515 |
}
|
| 516 |
if (neg)
|
| 517 |
*--cp = '-';
|
| 518 |
return(cp);
|
| 519 |
}
|
| 520 |
|
| 521 |
|
| 522 |
void
|
| 523 |
syntax( /* report syntax error and quit */
|
| 524 |
char *err
|
| 525 |
)
|
| 526 |
{
|
| 527 |
int i;
|
| 528 |
|
| 529 |
if ((infile != NULL) | (lineno != 0)) {
|
| 530 |
if (infile != NULL) eputs(infile);
|
| 531 |
if (lineno != 0) {
|
| 532 |
eputs(infile != NULL ? ", line " : "line ");
|
| 533 |
eputs(long2ascii((long)lineno));
|
| 534 |
}
|
| 535 |
eputs(":\n");
|
| 536 |
}
|
| 537 |
eputs(linbuf);
|
| 538 |
if (linbuf[strlen(linbuf)-1] != '\n')
|
| 539 |
eputs("\n");
|
| 540 |
for (i = 0; i < linepos-1; i++)
|
| 541 |
eputs(linbuf[i] == '\t' ? "\t" : " ");
|
| 542 |
eputs("^ ");
|
| 543 |
eputs(err);
|
| 544 |
eputs("\n");
|
| 545 |
quit(1);
|
| 546 |
}
|
| 547 |
|
| 548 |
|
| 549 |
void
|
| 550 |
addekid( /* add a child to ep */
|
| 551 |
EPNODE *ep,
|
| 552 |
EPNODE *ek
|
| 553 |
)
|
| 554 |
{
|
| 555 |
if (ep->nkids < 0) {
|
| 556 |
eputs("Cannot add kid to EPNODE array\n");
|
| 557 |
quit(1);
|
| 558 |
}
|
| 559 |
ep->nkids++;
|
| 560 |
if (ep->v.kid == NULL)
|
| 561 |
ep->v.kid = ek;
|
| 562 |
else {
|
| 563 |
for (ep = ep->v.kid; ep->sibling != NULL; ep = ep->sibling)
|
| 564 |
;
|
| 565 |
ep->sibling = ek;
|
| 566 |
}
|
| 567 |
ek->sibling = NULL; /* shouldn't be necessary */
|
| 568 |
}
|
| 569 |
|
| 570 |
|
| 571 |
char *
|
| 572 |
getname(void) /* scan an identifier */
|
| 573 |
{
|
| 574 |
static char str[RMAXWORD+1];
|
| 575 |
int i, lnext;
|
| 576 |
|
| 577 |
lnext = nextc;
|
| 578 |
for (i = 0; i < RMAXWORD && isid(lnext); i++, lnext = scan())
|
| 579 |
str[i] = lnext;
|
| 580 |
str[i] = '\0';
|
| 581 |
while (isid(lnext)) /* skip rest of name */
|
| 582 |
lnext = scan();
|
| 583 |
|
| 584 |
return(str);
|
| 585 |
}
|
| 586 |
|
| 587 |
|
| 588 |
int
|
| 589 |
getinum(void) /* scan a positive integer */
|
| 590 |
{
|
| 591 |
int n, lnext;
|
| 592 |
|
| 593 |
n = 0;
|
| 594 |
lnext = nextc;
|
| 595 |
while (isdigit(lnext)) {
|
| 596 |
n = n * 10 + lnext - '0';
|
| 597 |
lnext = scan();
|
| 598 |
}
|
| 599 |
return(n);
|
| 600 |
}
|
| 601 |
|
| 602 |
|
| 603 |
double
|
| 604 |
getnum(void) /* scan a positive float */
|
| 605 |
{
|
| 606 |
int i, lnext;
|
| 607 |
char str[RMAXWORD+1];
|
| 608 |
|
| 609 |
i = 0;
|
| 610 |
lnext = nextc;
|
| 611 |
while (isdigit(lnext) && i < RMAXWORD) {
|
| 612 |
str[i++] = lnext;
|
| 613 |
lnext = scan();
|
| 614 |
}
|
| 615 |
if ((lnext == '.') & (i < RMAXWORD)) {
|
| 616 |
str[i++] = lnext;
|
| 617 |
lnext = scan();
|
| 618 |
if (i == 1 && !isdigit(lnext))
|
| 619 |
syntax("badly formed number");
|
| 620 |
while (isdigit(lnext) && i < RMAXWORD) {
|
| 621 |
str[i++] = lnext;
|
| 622 |
lnext = scan();
|
| 623 |
}
|
| 624 |
}
|
| 625 |
if ((lnext == 'e') | (lnext == 'E') && i < RMAXWORD) {
|
| 626 |
str[i++] = lnext;
|
| 627 |
lnext = scan();
|
| 628 |
if ((lnext == '-') | (lnext == '+') && i < RMAXWORD) {
|
| 629 |
str[i++] = lnext;
|
| 630 |
lnext = scan();
|
| 631 |
}
|
| 632 |
if (!isdigit(lnext))
|
| 633 |
syntax("missing exponent");
|
| 634 |
while (isdigit(lnext) && i < RMAXWORD) {
|
| 635 |
str[i++] = lnext;
|
| 636 |
lnext = scan();
|
| 637 |
}
|
| 638 |
}
|
| 639 |
str[i] = '\0';
|
| 640 |
|
| 641 |
return(atof(str));
|
| 642 |
}
|
| 643 |
|
| 644 |
|
| 645 |
EPNODE *
|
| 646 |
getE1(void) /* E1 -> E1 ADDOP E2 */
|
| 647 |
/* E2 */
|
| 648 |
{
|
| 649 |
EPNODE *ep1, *ep2;
|
| 650 |
|
| 651 |
ep1 = getE2();
|
| 652 |
while ((nextc == '+') | (nextc == '-')) {
|
| 653 |
ep2 = newnode();
|
| 654 |
ep2->type = nextc;
|
| 655 |
scan();
|
| 656 |
addekid(ep2, ep1);
|
| 657 |
addekid(ep2, getE2());
|
| 658 |
if (esupport&E_RCONST &&
|
| 659 |
(ep1->type == NUM) & (ep1->sibling->type == NUM))
|
| 660 |
ep2 = rconst(ep2);
|
| 661 |
ep1 = ep2;
|
| 662 |
}
|
| 663 |
return(ep1);
|
| 664 |
}
|
| 665 |
|
| 666 |
|
| 667 |
EPNODE *
|
| 668 |
getE2(void) /* E2 -> E2 MULOP E3 */
|
| 669 |
/* E3 */
|
| 670 |
{
|
| 671 |
EPNODE *ep1, *ep2;
|
| 672 |
|
| 673 |
ep1 = getE3();
|
| 674 |
while ((nextc == '*') | (nextc == '/')) {
|
| 675 |
ep2 = newnode();
|
| 676 |
ep2->type = nextc;
|
| 677 |
scan();
|
| 678 |
addekid(ep2, ep1);
|
| 679 |
addekid(ep2, getE3());
|
| 680 |
if (esupport&E_RCONST) {
|
| 681 |
EPNODE *ep3 = ep1->sibling;
|
| 682 |
if ((ep1->type == NUM) & (ep3->type == NUM)) {
|
| 683 |
ep2 = rconst(ep2);
|
| 684 |
} else if (ep3->type == NUM) {
|
| 685 |
if (ep2->type == '/') {
|
| 686 |
if (ep3->v.num == 0)
|
| 687 |
syntax("divide by zero constant");
|
| 688 |
ep2->type = '*'; /* for speed */
|
| 689 |
ep3->v.num = 1./ep3->v.num;
|
| 690 |
} else if (ep3->v.num == 0) {
|
| 691 |
ep1->sibling = NULL; /* (E2 * 0) */
|
| 692 |
epfree(ep2,1);
|
| 693 |
ep2 = ep3;
|
| 694 |
}
|
| 695 |
} else if (ep1->type == NUM && ep1->v.num == 0) {
|
| 696 |
epfree(ep3,1); /* (0 * E3) or (0 / E3) */
|
| 697 |
ep1->sibling = NULL;
|
| 698 |
efree(ep2);
|
| 699 |
ep2 = ep1;
|
| 700 |
}
|
| 701 |
}
|
| 702 |
ep1 = ep2;
|
| 703 |
}
|
| 704 |
return(ep1);
|
| 705 |
}
|
| 706 |
|
| 707 |
|
| 708 |
EPNODE *
|
| 709 |
getE3(void) /* E3 -> E4 ^ E3 */
|
| 710 |
/* E4 */
|
| 711 |
{
|
| 712 |
EPNODE *ep1, *ep2;
|
| 713 |
|
| 714 |
ep1 = getE4();
|
| 715 |
if (nextc != '^')
|
| 716 |
return(ep1);
|
| 717 |
ep2 = newnode();
|
| 718 |
ep2->type = nextc;
|
| 719 |
scan();
|
| 720 |
addekid(ep2, ep1);
|
| 721 |
addekid(ep2, getE3());
|
| 722 |
if (esupport&E_RCONST) {
|
| 723 |
EPNODE *ep3 = ep1->sibling;
|
| 724 |
if ((ep1->type == NUM) & (ep3->type == NUM)) {
|
| 725 |
ep2 = rconst(ep2);
|
| 726 |
} else if (ep1->type == NUM && ep1->v.num == 0) {
|
| 727 |
epfree(ep3,1); /* (0 ^ E3) */
|
| 728 |
ep1->sibling = NULL;
|
| 729 |
efree(ep2);
|
| 730 |
ep2 = ep1;
|
| 731 |
} else if ((ep3->type == NUM && ep3->v.num == 0) |
|
| 732 |
(ep1->type == NUM && ep1->v.num == 1)) {
|
| 733 |
epfree(ep2,1); /* (E4 ^ 0) or (1 ^ E3) */
|
| 734 |
ep2 = newnode();
|
| 735 |
ep2->type = NUM;
|
| 736 |
ep2->v.num = 1;
|
| 737 |
} else if (ep3->type == NUM && ep3->v.num == 1) {
|
| 738 |
efree(ep3); /* (E4 ^ 1) */
|
| 739 |
ep1->sibling = NULL;
|
| 740 |
efree(ep2);
|
| 741 |
ep2 = ep1;
|
| 742 |
}
|
| 743 |
}
|
| 744 |
return(ep2);
|
| 745 |
}
|
| 746 |
|
| 747 |
|
| 748 |
EPNODE *
|
| 749 |
getE4(void) /* E4 -> ADDOP E5 */
|
| 750 |
/* E5 */
|
| 751 |
{
|
| 752 |
EPNODE *ep1, *ep2;
|
| 753 |
|
| 754 |
if (nextc == '-') {
|
| 755 |
scan();
|
| 756 |
ep2 = getE5();
|
| 757 |
if (ep2->type == NUM) {
|
| 758 |
ep2->v.num = -ep2->v.num;
|
| 759 |
return(ep2);
|
| 760 |
}
|
| 761 |
if (ep2->type == UMINUS) { /* don't generate -(-E5) */
|
| 762 |
ep1 = ep2->v.kid;
|
| 763 |
efree(ep2);
|
| 764 |
return(ep1);
|
| 765 |
}
|
| 766 |
ep1 = newnode();
|
| 767 |
ep1->type = UMINUS;
|
| 768 |
addekid(ep1, ep2);
|
| 769 |
return(ep1);
|
| 770 |
}
|
| 771 |
if (nextc == '+')
|
| 772 |
scan();
|
| 773 |
return(getE5());
|
| 774 |
}
|
| 775 |
|
| 776 |
|
| 777 |
EPNODE *
|
| 778 |
getE5(void) /* E5 -> (E1) */
|
| 779 |
/* VAR */
|
| 780 |
/* NUM */
|
| 781 |
/* $N */
|
| 782 |
/* FUNC(E1,..) */
|
| 783 |
/* ARG */
|
| 784 |
{
|
| 785 |
int i;
|
| 786 |
char *nam;
|
| 787 |
EPNODE *ep1, *ep2;
|
| 788 |
|
| 789 |
if (nextc == '(') {
|
| 790 |
scan();
|
| 791 |
ep1 = getE1();
|
| 792 |
if (nextc != ')')
|
| 793 |
syntax("')' expected");
|
| 794 |
scan();
|
| 795 |
return(ep1);
|
| 796 |
}
|
| 797 |
if (esupport&E_INCHAN && nextc == '$') {
|
| 798 |
scan();
|
| 799 |
ep1 = newnode();
|
| 800 |
ep1->type = CHAN;
|
| 801 |
ep1->v.chan = getinum();
|
| 802 |
return(ep1);
|
| 803 |
}
|
| 804 |
if (esupport&(E_VARIABLE|E_FUNCTION) &&
|
| 805 |
(isalpha(nextc) | (nextc == CNTXMARK))) {
|
| 806 |
nam = getname();
|
| 807 |
ep1 = NULL;
|
| 808 |
if ((esupport&(E_VARIABLE|E_FUNCTION)) == (E_VARIABLE|E_FUNCTION)
|
| 809 |
&& curfunc != NULL)
|
| 810 |
for (i = 1, ep2 = curfunc->v.kid->sibling;
|
| 811 |
ep2 != NULL; i++, ep2 = ep2->sibling)
|
| 812 |
if (!strcmp(ep2->v.name, nam)) {
|
| 813 |
ep1 = newnode();
|
| 814 |
ep1->type = ARG;
|
| 815 |
ep1->v.chan = i;
|
| 816 |
break;
|
| 817 |
}
|
| 818 |
if (ep1 == NULL) {
|
| 819 |
ep1 = newnode();
|
| 820 |
ep1->type = VAR;
|
| 821 |
ep1->v.ln = varinsert(nam);
|
| 822 |
}
|
| 823 |
if (esupport&E_FUNCTION && nextc == '(') {
|
| 824 |
ep2 = newnode();
|
| 825 |
ep2->type = FUNC;
|
| 826 |
addekid(ep2, ep1);
|
| 827 |
ep1 = ep2;
|
| 828 |
do {
|
| 829 |
scan();
|
| 830 |
addekid(ep1, getE1());
|
| 831 |
} while (nextc == ',');
|
| 832 |
if (nextc != ')')
|
| 833 |
syntax("')' expected");
|
| 834 |
scan();
|
| 835 |
} else if (!(esupport&E_VARIABLE))
|
| 836 |
syntax("'(' expected");
|
| 837 |
if (esupport&E_RCONST && isconstvar(ep1))
|
| 838 |
ep1 = rconst(ep1);
|
| 839 |
return(ep1);
|
| 840 |
}
|
| 841 |
if (isdecimal(nextc)) {
|
| 842 |
ep1 = newnode();
|
| 843 |
ep1->type = NUM;
|
| 844 |
ep1->v.num = getnum();
|
| 845 |
return(ep1);
|
| 846 |
}
|
| 847 |
syntax("unexpected character");
|
| 848 |
return NULL; /* pro forma return */
|
| 849 |
}
|
| 850 |
|
| 851 |
|
| 852 |
EPNODE *
|
| 853 |
rconst( /* reduce a constant expression */
|
| 854 |
EPNODE *epar
|
| 855 |
)
|
| 856 |
{
|
| 857 |
EPNODE *ep;
|
| 858 |
|
| 859 |
ep = newnode();
|
| 860 |
ep->type = NUM;
|
| 861 |
errno = 0;
|
| 862 |
ep->v.num = evalue(epar);
|
| 863 |
if ((errno == EDOM) | (errno == ERANGE))
|
| 864 |
syntax("bad constant expression");
|
| 865 |
epfree(epar,1);
|
| 866 |
|
| 867 |
return(ep);
|
| 868 |
}
|
| 869 |
|
| 870 |
|
| 871 |
int
|
| 872 |
isconstvar( /* is ep linked to a constant expression? */
|
| 873 |
EPNODE *ep
|
| 874 |
)
|
| 875 |
{
|
| 876 |
EPNODE *ep1;
|
| 877 |
|
| 878 |
if (esupport&E_FUNCTION && ep->type == FUNC) {
|
| 879 |
if (!isconstfun(ep->v.kid))
|
| 880 |
return(0);
|
| 881 |
for (ep1 = ep->v.kid->sibling; ep1 != NULL; ep1 = ep1->sibling)
|
| 882 |
if (ep1->type != NUM && !isconstfun(ep1))
|
| 883 |
return(0);
|
| 884 |
return(1);
|
| 885 |
}
|
| 886 |
if (ep->type != VAR)
|
| 887 |
return(0);
|
| 888 |
ep1 = ep->v.ln->def;
|
| 889 |
if (ep1 == NULL || ep1->type != ':')
|
| 890 |
return(0);
|
| 891 |
if (esupport&E_FUNCTION && ep1->v.kid->type != SYM)
|
| 892 |
return(0);
|
| 893 |
return(1);
|
| 894 |
}
|
| 895 |
|
| 896 |
|
| 897 |
int
|
| 898 |
isconstfun( /* is ep linked to a constant function? */
|
| 899 |
EPNODE *ep
|
| 900 |
)
|
| 901 |
{
|
| 902 |
EPNODE *dp;
|
| 903 |
LIBR *lp;
|
| 904 |
|
| 905 |
if (ep->type != VAR)
|
| 906 |
return(0);
|
| 907 |
if ((dp = ep->v.ln->def) != NULL) {
|
| 908 |
if (dp->v.kid->type == FUNC)
|
| 909 |
return(dp->type == ':');
|
| 910 |
else
|
| 911 |
return(0); /* don't identify masked library functions */
|
| 912 |
}
|
| 913 |
if ((lp = ep->v.ln->lib) != NULL)
|
| 914 |
return(lp->atyp == ':');
|
| 915 |
return(0);
|
| 916 |
}
|
