| 1 |
/* Copyright (c) 1997 Regents of the University of California */ |
| 2 |
|
| 3 |
#ifndef lint |
| 4 |
static char SCCSid[] = "$SunId$ LBL"; |
| 5 |
#endif |
| 6 |
|
| 7 |
/* |
| 8 |
* Store variable definitions. |
| 9 |
* |
| 10 |
* 7/1/85 Greg Ward |
| 11 |
* |
| 12 |
* 11/11/85 Added conditional compiles (OUTCHAN) for control output. |
| 13 |
* |
| 14 |
* 4/2/86 Added conditional compiles for function definitions (FUNCTION). |
| 15 |
* |
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* 1/15/88 Added clock for caching of variable values. |
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* |
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* 11/16/88 Added VARDEF structure for hard linking. |
| 19 |
* |
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* 5/31/90 Added conditional compile (REDEFW) for redefinition warning. |
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* |
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* 4/23/91 Added ':' assignment for constant expressions |
| 23 |
* |
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* 8/7/91 Added optional context path to append to variable names |
| 25 |
*/ |
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|
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#include <stdio.h> |
| 28 |
|
| 29 |
#include <ctype.h> |
| 30 |
|
| 31 |
#include "calcomp.h" |
| 32 |
|
| 33 |
#ifndef NHASH |
| 34 |
#define NHASH 521 /* hash size (a prime!) */ |
| 35 |
#endif |
| 36 |
|
| 37 |
#define hash(s) (shash(s)%NHASH) |
| 38 |
|
| 39 |
#define newnode() (EPNODE *)ecalloc(1, sizeof(EPNODE)) |
| 40 |
|
| 41 |
extern char *ecalloc(), *emalloc(), *savestr(), *strcpy(); |
| 42 |
|
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static double dvalue(); |
| 44 |
|
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unsigned long eclock = 0; /* value storage timer */ |
| 46 |
|
| 47 |
#define MAXCNTX 1023 /* maximum context length */ |
| 48 |
|
| 49 |
static char context[MAXCNTX+1]; /* current context path */ |
| 50 |
|
| 51 |
static VARDEF *hashtbl[NHASH]; /* definition list */ |
| 52 |
static int htndx; /* index for */ |
| 53 |
static VARDEF *htpos; /* ...dfirst() and */ |
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#ifdef OUTCHAN |
| 55 |
static EPNODE *ochpos; /* ...dnext */ |
| 56 |
static EPNODE *outchan; |
| 57 |
#endif |
| 58 |
|
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#ifdef FUNCTION |
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EPNODE *curfunc = NULL; |
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#define dname(ep) ((ep)->v.kid->type == SYM ? \ |
| 62 |
(ep)->v.kid->v.name : \ |
| 63 |
(ep)->v.kid->v.kid->v.name) |
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#else |
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#define dname(ep) ((ep)->v.kid->v.name) |
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#endif |
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|
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|
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fcompile(fname) /* get definitions from a file */ |
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char *fname; |
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{ |
| 72 |
FILE *fp; |
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|
| 74 |
if (fname == NULL) |
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fp = stdin; |
| 76 |
else if ((fp = fopen(fname, "r")) == NULL) { |
| 77 |
eputs(fname); |
| 78 |
eputs(": cannot open\n"); |
| 79 |
quit(1); |
| 80 |
} |
| 81 |
initfile(fp, fname, 0); |
| 82 |
while (nextc != EOF) |
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getstatement(); |
| 84 |
if (fname != NULL) |
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fclose(fp); |
| 86 |
} |
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|
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|
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scompile(str, fn, ln) /* get definitions from a string */ |
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char *str; |
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char *fn; |
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int ln; |
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{ |
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initstr(str, fn, ln); |
| 95 |
while (nextc != EOF) |
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getstatement(); |
| 97 |
} |
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|
| 99 |
|
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double |
| 101 |
varvalue(vname) /* return a variable's value */ |
| 102 |
char *vname; |
| 103 |
{ |
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return(dvalue(vname, dlookup(vname))); |
| 105 |
} |
| 106 |
|
| 107 |
|
| 108 |
double |
| 109 |
evariable(ep) /* evaluate a variable */ |
| 110 |
EPNODE *ep; |
| 111 |
{ |
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register VARDEF *dp = ep->v.ln; |
| 113 |
|
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return(dvalue(dp->name, dp->def)); |
| 115 |
} |
| 116 |
|
| 117 |
|
| 118 |
varset(vname, assign, val) /* set a variable's value */ |
| 119 |
char *vname; |
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int assign; |
| 121 |
double val; |
| 122 |
{ |
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char *qname; |
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register EPNODE *ep1, *ep2; |
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/* get qualified name */ |
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qname = qualname(vname, 0); |
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/* check for quick set */ |
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if ((ep1 = dlookup(qname)) != NULL && ep1->v.kid->type == SYM) { |
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ep2 = ep1->v.kid->sibling; |
| 130 |
if (ep2->type == NUM) { |
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ep2->v.num = val; |
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ep1->type = assign; |
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return; |
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} |
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} |
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/* hand build definition */ |
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ep1 = newnode(); |
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ep1->type = assign; |
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ep2 = newnode(); |
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ep2->type = SYM; |
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ep2->v.name = savestr(vname); |
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addekid(ep1, ep2); |
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ep2 = newnode(); |
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ep2->type = NUM; |
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ep2->v.num = val; |
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addekid(ep1, ep2); |
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dremove(qname); |
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dpush(qname, ep1); |
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} |
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|
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|
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dclear(name) /* delete variable definitions of name */ |
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char *name; |
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{ |
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register EPNODE *ep; |
| 156 |
|
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while ((ep = dpop(name)) != NULL) { |
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if (ep->type == ':') { |
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dpush(name, ep); /* don't clear constants */ |
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return; |
| 161 |
} |
| 162 |
epfree(ep); |
| 163 |
} |
| 164 |
} |
| 165 |
|
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|
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dremove(name) /* delete all definitions of name */ |
| 168 |
char *name; |
| 169 |
{ |
| 170 |
register EPNODE *ep; |
| 171 |
|
| 172 |
while ((ep = dpop(name)) != NULL) |
| 173 |
epfree(ep); |
| 174 |
} |
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|
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|
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vardefined(name) /* return non-zero if variable defined */ |
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char *name; |
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{ |
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register EPNODE *dp; |
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|
| 182 |
return((dp = dlookup(name)) != NULL && dp->v.kid->type == SYM); |
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} |
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|
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|
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char * |
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setcontext(ctx) /* set a new context path */ |
| 188 |
register char *ctx; |
| 189 |
{ |
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register char *cpp; |
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|
| 192 |
if (ctx == NULL) |
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return(context); /* just asking */ |
| 194 |
while (*ctx == CNTXMARK) |
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ctx++; /* skip past marks */ |
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if (!*ctx) { |
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context[0] = '\0'; /* empty means clear context */ |
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return(context); |
| 199 |
} |
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cpp = context; /* start context with mark */ |
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*cpp++ = CNTXMARK; |
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do { /* carefully copy new context */ |
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if (cpp >= context+MAXCNTX) |
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break; /* just copy what we can */ |
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if (isid(*ctx)) |
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*cpp++ = *ctx++; |
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else { |
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*cpp++ = '_'; ctx++; |
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} |
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} while (*ctx); |
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while (cpp[-1] == CNTXMARK) /* cannot end in context mark */ |
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cpp--; |
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*cpp = '\0'; |
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return(context); |
| 215 |
} |
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|
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|
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char * |
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pushcontext(ctx) /* push on another context */ |
| 220 |
char *ctx; |
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{ |
| 222 |
extern char *strncpy(), *strcpy(); |
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char oldcontext[MAXCNTX+1]; |
| 224 |
register int n; |
| 225 |
|
| 226 |
strcpy(oldcontext, context); /* save old context */ |
| 227 |
setcontext(ctx); /* set new context */ |
| 228 |
n = strlen(context); /* tack on old */ |
| 229 |
if (n+strlen(oldcontext) > MAXCNTX) { |
| 230 |
strncpy(context+n, oldcontext, MAXCNTX-n); |
| 231 |
context[MAXCNTX] = '\0'; |
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} else |
| 233 |
strcpy(context+n, oldcontext); |
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return(context); |
| 235 |
} |
| 236 |
|
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|
| 238 |
char * |
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popcontext() /* pop off top context */ |
| 240 |
{ |
| 241 |
register char *cp1, *cp2; |
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|
| 243 |
if (!context[0]) /* nothing left to pop */ |
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return(context); |
| 245 |
cp2 = context; /* find mark */ |
| 246 |
while (*++cp2 && *cp2 != CNTXMARK) |
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; |
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cp1 = context; /* copy tail to front */ |
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while (*cp1++ = *cp2++) |
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; |
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return(context); |
| 252 |
} |
| 253 |
|
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|
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char * |
| 256 |
qualname(nam, lvl) /* get qualified name */ |
| 257 |
register char *nam; |
| 258 |
int lvl; |
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{ |
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static char nambuf[MAXWORD+1]; |
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register char *cp = nambuf, *cpp; |
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/* check for explicit local */ |
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if (*nam == CNTXMARK) |
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if (lvl > 0) /* only action is to refuse search */ |
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return(NULL); |
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else |
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nam++; |
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else if (nam == nambuf) /* check for repeat call */ |
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return(lvl > 0 ? NULL : nam); |
| 270 |
/* copy name to static buffer */ |
| 271 |
while (*nam) { |
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if (cp >= nambuf+MAXWORD) |
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goto toolong; |
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*cp++ = *nam++; |
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} |
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/* check for explicit global */ |
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if (cp > nambuf && cp[-1] == CNTXMARK) { |
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if (lvl > 0) |
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return(NULL); |
| 280 |
*--cp = '\0'; |
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return(nambuf); /* already qualified */ |
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} |
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cpp = context; /* else skip the requested levels */ |
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while (lvl-- > 0) { |
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if (!*cpp) |
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return(NULL); /* return NULL if past global level */ |
| 287 |
while (*++cpp && *cpp != CNTXMARK) |
| 288 |
; |
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} |
| 290 |
while (*cpp) { /* copy context to static buffer */ |
| 291 |
if (cp >= nambuf+MAXWORD) |
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goto toolong; |
| 293 |
*cp++ = *cpp++; |
| 294 |
} |
| 295 |
toolong: |
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*cp = '\0'; |
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return(nambuf); /* return qualified name */ |
| 298 |
} |
| 299 |
|
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|
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incontext(qn) /* is qualified name in current context? */ |
| 302 |
register char *qn; |
| 303 |
{ |
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if (!context[0]) /* global context accepts all */ |
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return(1); |
| 306 |
while (*qn && *qn != CNTXMARK) /* find context mark */ |
| 307 |
qn++; |
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return(!strcmp(qn, context)); |
| 309 |
} |
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|
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|
| 312 |
#ifdef OUTCHAN |
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chanout(cs) /* set output channels */ |
| 314 |
int (*cs)(); |
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{ |
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register EPNODE *ep; |
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|
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for (ep = outchan; ep != NULL; ep = ep->sibling) |
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(*cs)(ep->v.kid->v.chan, evalue(ep->v.kid->sibling)); |
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|
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} |
| 322 |
#endif |
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|
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|
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dcleanup(lvl) /* clear definitions (0->vars,1->output,2->consts) */ |
| 326 |
int lvl; |
| 327 |
{ |
| 328 |
register int i; |
| 329 |
register VARDEF *vp; |
| 330 |
register EPNODE *ep; |
| 331 |
/* if context is global, clear all */ |
| 332 |
for (i = 0; i < NHASH; i++) |
| 333 |
for (vp = hashtbl[i]; vp != NULL; vp = vp->next) |
| 334 |
if (incontext(vp->name)) |
| 335 |
if (lvl >= 2) |
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dremove(vp->name); |
| 337 |
else |
| 338 |
dclear(vp->name); |
| 339 |
#ifdef OUTCHAN |
| 340 |
if (lvl >= 1) { |
| 341 |
for (ep = outchan; ep != NULL; ep = ep->sibling) |
| 342 |
epfree(ep); |
| 343 |
outchan = NULL; |
| 344 |
} |
| 345 |
#endif |
| 346 |
} |
| 347 |
|
| 348 |
|
| 349 |
EPNODE * |
| 350 |
dlookup(name) /* look up a definition */ |
| 351 |
char *name; |
| 352 |
{ |
| 353 |
register VARDEF *vp; |
| 354 |
|
| 355 |
if ((vp = varlookup(name)) == NULL) |
| 356 |
return(NULL); |
| 357 |
return(vp->def); |
| 358 |
} |
| 359 |
|
| 360 |
|
| 361 |
VARDEF * |
| 362 |
varlookup(name) /* look up a variable */ |
| 363 |
char *name; |
| 364 |
{ |
| 365 |
int lvl = 0; |
| 366 |
register char *qname; |
| 367 |
register VARDEF *vp; |
| 368 |
/* find most qualified match */ |
| 369 |
while ((qname = qualname(name, lvl++)) != NULL) |
| 370 |
for (vp = hashtbl[hash(qname)]; vp != NULL; vp = vp->next) |
| 371 |
if (!strcmp(vp->name, qname)) |
| 372 |
return(vp); |
| 373 |
return(NULL); |
| 374 |
} |
| 375 |
|
| 376 |
|
| 377 |
VARDEF * |
| 378 |
varinsert(name) /* get a link to a variable */ |
| 379 |
char *name; |
| 380 |
{ |
| 381 |
register VARDEF *vp; |
| 382 |
int hv; |
| 383 |
|
| 384 |
if ((vp = varlookup(name)) != NULL) { |
| 385 |
vp->nlinks++; |
| 386 |
return(vp); |
| 387 |
} |
| 388 |
vp = (VARDEF *)emalloc(sizeof(VARDEF)); |
| 389 |
#ifdef FUNCTION |
| 390 |
vp->lib = liblookup(name); |
| 391 |
#else |
| 392 |
vp->lib = NULL; |
| 393 |
#endif |
| 394 |
if (vp->lib == NULL) /* if name not in library */ |
| 395 |
name = qualname(name, 0); /* use fully qualified version */ |
| 396 |
hv = hash(name); |
| 397 |
vp->name = savestr(name); |
| 398 |
vp->nlinks = 1; |
| 399 |
vp->def = NULL; |
| 400 |
vp->next = hashtbl[hv]; |
| 401 |
hashtbl[hv] = vp; |
| 402 |
return(vp); |
| 403 |
} |
| 404 |
|
| 405 |
|
| 406 |
#ifdef FUNCTION |
| 407 |
libupdate(fn) /* update library links */ |
| 408 |
char *fn; |
| 409 |
{ |
| 410 |
register int i; |
| 411 |
register VARDEF *vp; |
| 412 |
/* if fn is NULL then relink all */ |
| 413 |
for (i = 0; i < NHASH; i++) |
| 414 |
for (vp = hashtbl[i]; vp != NULL; vp = vp->next) |
| 415 |
if (vp->lib != NULL || fn == NULL || !strcmp(fn, vp->name)) |
| 416 |
vp->lib = liblookup(vp->name); |
| 417 |
} |
| 418 |
#endif |
| 419 |
|
| 420 |
|
| 421 |
varfree(ln) /* release link to variable */ |
| 422 |
register VARDEF *ln; |
| 423 |
{ |
| 424 |
register VARDEF *vp; |
| 425 |
int hv; |
| 426 |
|
| 427 |
if (--ln->nlinks > 0) |
| 428 |
return; /* still active */ |
| 429 |
|
| 430 |
hv = hash(ln->name); |
| 431 |
vp = hashtbl[hv]; |
| 432 |
if (vp == ln) |
| 433 |
hashtbl[hv] = vp->next; |
| 434 |
else { |
| 435 |
while (vp->next != ln) /* must be in list */ |
| 436 |
vp = vp->next; |
| 437 |
vp->next = ln->next; |
| 438 |
} |
| 439 |
freestr(ln->name); |
| 440 |
efree((char *)ln); |
| 441 |
} |
| 442 |
|
| 443 |
|
| 444 |
EPNODE * |
| 445 |
dfirst() /* return pointer to first definition */ |
| 446 |
{ |
| 447 |
htndx = 0; |
| 448 |
htpos = NULL; |
| 449 |
#ifdef OUTCHAN |
| 450 |
ochpos = outchan; |
| 451 |
#endif |
| 452 |
return(dnext()); |
| 453 |
} |
| 454 |
|
| 455 |
|
| 456 |
EPNODE * |
| 457 |
dnext() /* return pointer to next definition */ |
| 458 |
{ |
| 459 |
register EPNODE *ep; |
| 460 |
register char *nm; |
| 461 |
|
| 462 |
while (htndx < NHASH) { |
| 463 |
if (htpos == NULL) |
| 464 |
htpos = hashtbl[htndx++]; |
| 465 |
while (htpos != NULL) { |
| 466 |
ep = htpos->def; |
| 467 |
nm = htpos->name; |
| 468 |
htpos = htpos->next; |
| 469 |
if (ep != NULL && incontext(nm)) |
| 470 |
return(ep); |
| 471 |
} |
| 472 |
} |
| 473 |
#ifdef OUTCHAN |
| 474 |
if ((ep = ochpos) != NULL) |
| 475 |
ochpos = ep->sibling; |
| 476 |
return(ep); |
| 477 |
#else |
| 478 |
return(NULL); |
| 479 |
#endif |
| 480 |
} |
| 481 |
|
| 482 |
|
| 483 |
EPNODE * |
| 484 |
dpop(name) /* pop a definition */ |
| 485 |
char *name; |
| 486 |
{ |
| 487 |
register VARDEF *vp; |
| 488 |
register EPNODE *dp; |
| 489 |
|
| 490 |
if ((vp = varlookup(name)) == NULL || vp->def == NULL) |
| 491 |
return(NULL); |
| 492 |
dp = vp->def; |
| 493 |
vp->def = dp->sibling; |
| 494 |
varfree(vp); |
| 495 |
return(dp); |
| 496 |
} |
| 497 |
|
| 498 |
|
| 499 |
dpush(nm, ep) /* push on a definition */ |
| 500 |
char *nm; |
| 501 |
register EPNODE *ep; |
| 502 |
{ |
| 503 |
register VARDEF *vp; |
| 504 |
|
| 505 |
vp = varinsert(nm); |
| 506 |
ep->sibling = vp->def; |
| 507 |
vp->def = ep; |
| 508 |
} |
| 509 |
|
| 510 |
|
| 511 |
#ifdef OUTCHAN |
| 512 |
addchan(sp) /* add an output channel assignment */ |
| 513 |
EPNODE *sp; |
| 514 |
{ |
| 515 |
int ch = sp->v.kid->v.chan; |
| 516 |
register EPNODE *ep, *epl; |
| 517 |
|
| 518 |
for (epl = NULL, ep = outchan; ep != NULL; epl = ep, ep = ep->sibling) |
| 519 |
if (ep->v.kid->v.chan >= ch) { |
| 520 |
if (epl != NULL) |
| 521 |
epl->sibling = sp; |
| 522 |
else |
| 523 |
outchan = sp; |
| 524 |
if (ep->v.kid->v.chan > ch) |
| 525 |
sp->sibling = ep; |
| 526 |
else { |
| 527 |
sp->sibling = ep->sibling; |
| 528 |
epfree(ep); |
| 529 |
} |
| 530 |
return; |
| 531 |
} |
| 532 |
if (epl != NULL) |
| 533 |
epl->sibling = sp; |
| 534 |
else |
| 535 |
outchan = sp; |
| 536 |
sp->sibling = NULL; |
| 537 |
|
| 538 |
} |
| 539 |
#endif |
| 540 |
|
| 541 |
|
| 542 |
getstatement() /* get next statement */ |
| 543 |
{ |
| 544 |
register EPNODE *ep; |
| 545 |
char *qname; |
| 546 |
register VARDEF *vdef; |
| 547 |
|
| 548 |
if (nextc == ';') { /* empty statement */ |
| 549 |
scan(); |
| 550 |
return; |
| 551 |
} |
| 552 |
#ifdef OUTCHAN |
| 553 |
if (nextc == '$') { /* channel assignment */ |
| 554 |
ep = getchan(); |
| 555 |
addchan(ep); |
| 556 |
} else |
| 557 |
#endif |
| 558 |
{ /* ordinary definition */ |
| 559 |
ep = getdefn(); |
| 560 |
qname = qualname(dname(ep), 0); |
| 561 |
#ifdef REDEFW |
| 562 |
if ((vdef = varlookup(qname)) != NULL) |
| 563 |
if (vdef->def != NULL && epcmp(ep, vdef->def)) { |
| 564 |
wputs(qname); |
| 565 |
if (vdef->def->type == ':') |
| 566 |
wputs(": redefined constant expression\n"); |
| 567 |
else |
| 568 |
wputs(": redefined\n"); |
| 569 |
} |
| 570 |
#ifdef FUNCTION |
| 571 |
else if (ep->v.kid->type == FUNC && vdef->lib != NULL) { |
| 572 |
wputs(qname); |
| 573 |
wputs(": definition hides library function\n"); |
| 574 |
} |
| 575 |
#endif |
| 576 |
#endif |
| 577 |
if (ep->type == ':') |
| 578 |
dremove(qname); |
| 579 |
else |
| 580 |
dclear(qname); |
| 581 |
dpush(qname, ep); |
| 582 |
} |
| 583 |
if (nextc != EOF) { |
| 584 |
if (nextc != ';') |
| 585 |
syntax("';' expected"); |
| 586 |
scan(); |
| 587 |
} |
| 588 |
} |
| 589 |
|
| 590 |
|
| 591 |
EPNODE * |
| 592 |
getdefn() /* A -> SYM = E1 */ |
| 593 |
/* SYM : E1 */ |
| 594 |
/* FUNC(SYM,..) = E1 */ |
| 595 |
/* FUNC(SYM,..) : E1 */ |
| 596 |
{ |
| 597 |
register EPNODE *ep1, *ep2; |
| 598 |
|
| 599 |
if (!isalpha(nextc) && nextc != CNTXMARK) |
| 600 |
syntax("illegal variable name"); |
| 601 |
|
| 602 |
ep1 = newnode(); |
| 603 |
ep1->type = SYM; |
| 604 |
ep1->v.name = savestr(getname()); |
| 605 |
|
| 606 |
#ifdef FUNCTION |
| 607 |
if (nextc == '(') { |
| 608 |
ep2 = newnode(); |
| 609 |
ep2->type = FUNC; |
| 610 |
addekid(ep2, ep1); |
| 611 |
ep1 = ep2; |
| 612 |
do { |
| 613 |
scan(); |
| 614 |
if (!isalpha(nextc)) |
| 615 |
syntax("illegal variable name"); |
| 616 |
ep2 = newnode(); |
| 617 |
ep2->type = SYM; |
| 618 |
ep2->v.name = savestr(getname()); |
| 619 |
addekid(ep1, ep2); |
| 620 |
} while (nextc == ','); |
| 621 |
if (nextc != ')') |
| 622 |
syntax("')' expected"); |
| 623 |
scan(); |
| 624 |
curfunc = ep1; |
| 625 |
} |
| 626 |
#endif |
| 627 |
|
| 628 |
if (nextc != '=' && nextc != ':') |
| 629 |
syntax("'=' or ':' expected"); |
| 630 |
|
| 631 |
ep2 = newnode(); |
| 632 |
ep2->type = nextc; |
| 633 |
scan(); |
| 634 |
addekid(ep2, ep1); |
| 635 |
addekid(ep2, getE1()); |
| 636 |
|
| 637 |
if ( |
| 638 |
#ifdef FUNCTION |
| 639 |
ep1->type == SYM && |
| 640 |
#endif |
| 641 |
ep1->sibling->type != NUM) { |
| 642 |
ep1 = newnode(); |
| 643 |
ep1->type = TICK; |
| 644 |
ep1->v.tick = 0; |
| 645 |
addekid(ep2, ep1); |
| 646 |
ep1 = newnode(); |
| 647 |
ep1->type = NUM; |
| 648 |
addekid(ep2, ep1); |
| 649 |
} |
| 650 |
|
| 651 |
#ifdef FUNCTION |
| 652 |
curfunc = NULL; |
| 653 |
#endif |
| 654 |
|
| 655 |
return(ep2); |
| 656 |
} |
| 657 |
|
| 658 |
|
| 659 |
#ifdef OUTCHAN |
| 660 |
EPNODE * |
| 661 |
getchan() /* A -> $N = E1 */ |
| 662 |
{ |
| 663 |
register EPNODE *ep1, *ep2; |
| 664 |
|
| 665 |
if (nextc != '$') |
| 666 |
syntax("missing '$'"); |
| 667 |
scan(); |
| 668 |
|
| 669 |
ep1 = newnode(); |
| 670 |
ep1->type = CHAN; |
| 671 |
ep1->v.chan = getinum(); |
| 672 |
|
| 673 |
if (nextc != '=') |
| 674 |
syntax("'=' expected"); |
| 675 |
scan(); |
| 676 |
|
| 677 |
ep2 = newnode(); |
| 678 |
ep2->type = '='; |
| 679 |
addekid(ep2, ep1); |
| 680 |
addekid(ep2, getE1()); |
| 681 |
|
| 682 |
return(ep2); |
| 683 |
} |
| 684 |
#endif |
| 685 |
|
| 686 |
|
| 687 |
|
| 688 |
/* |
| 689 |
* The following routines are for internal use only: |
| 690 |
*/ |
| 691 |
|
| 692 |
|
| 693 |
static double |
| 694 |
dvalue(name, d) /* evaluate a variable */ |
| 695 |
char *name; |
| 696 |
EPNODE *d; |
| 697 |
{ |
| 698 |
register EPNODE *ep1, *ep2; |
| 699 |
|
| 700 |
if (d == NULL || d->v.kid->type != SYM) { |
| 701 |
eputs(name); |
| 702 |
eputs(": undefined variable\n"); |
| 703 |
quit(1); |
| 704 |
} |
| 705 |
ep1 = d->v.kid->sibling; /* get expression */ |
| 706 |
if (ep1->type == NUM) |
| 707 |
return(ep1->v.num); /* return if number */ |
| 708 |
ep2 = ep1->sibling; /* check time */ |
| 709 |
if (ep2->v.tick == 0 || ep2->v.tick < eclock) { |
| 710 |
ep2->v.tick = d->type == ':' ? ~0L : eclock; |
| 711 |
ep2 = ep2->sibling; |
| 712 |
ep2->v.num = evalue(ep1); /* needs new value */ |
| 713 |
} else |
| 714 |
ep2 = ep2->sibling; /* else reuse old value */ |
| 715 |
|
| 716 |
return(ep2->v.num); |
| 717 |
} |
