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/* Copyright (c) 1986 Regents of the University of California */ |
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|
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#ifndef lint |
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static char SCCSid[] = "$SunId$ LBL"; |
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#endif |
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|
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/* |
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* Store variable definitions. |
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* |
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* 7/1/85 Greg Ward |
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* |
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* 11/11/85 Added conditional compiles (OUTCHAN) for control output. |
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* |
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* 4/2/86 Added conditional compiles for function definitions (FUNCTION). |
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* |
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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. |
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* |
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* 5/31/90 Added conditional compile (REDEFW) for redefinition warning. |
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*/ |
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|
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#include <stdio.h> |
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|
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#include <ctype.h> |
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|
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#include "calcomp.h" |
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|
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#ifndef NHASH |
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#define NHASH 521 /* hash size (a prime!) */ |
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#endif |
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|
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#define newnode() (EPNODE *)ecalloc(1, sizeof(EPNODE)) |
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|
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extern char *ecalloc(), *savestr(); |
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|
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static double dvalue(); |
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|
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long eclock = -1; /* value storage timer */ |
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|
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static VARDEF *hashtbl[NHASH]; /* definition list */ |
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static int htndx; /* index for */ |
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static VARDEF *htpos; /* ...dfirst() and */ |
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#ifdef OUTCHAN |
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static EPNODE *ochpos; /* ...dnext */ |
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static EPNODE *outchan; |
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#endif |
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|
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#ifdef FUNCTION |
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EPNODE *curfunc; |
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#define dname(ep) ((ep)->v.kid->type == SYM ? \ |
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(ep)->v.kid->v.name : \ |
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(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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{ |
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FILE *fp; |
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|
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if (fname == NULL) |
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fp = stdin; |
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else if ((fp = fopen(fname, "r")) == NULL) { |
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eputs(fname); |
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eputs(": cannot open\n"); |
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quit(1); |
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} |
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initfile(fp, fname, 0); |
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while (nextc != EOF) |
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loaddefn(); |
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if (fname != NULL) |
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fclose(fp); |
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} |
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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); |
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while (nextc != EOF) |
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loaddefn(); |
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} |
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|
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|
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double |
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varvalue(vname) /* return a variable's value */ |
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char *vname; |
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{ |
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return(dvalue(vname, dlookup(vname))); |
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} |
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|
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|
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double |
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evariable(ep) /* evaluate a variable */ |
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EPNODE *ep; |
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{ |
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register VARDEF *dp = ep->v.ln; |
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|
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return(dvalue(dp->name, dp->def)); |
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} |
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|
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|
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varset(vname, val) /* set a variable's value */ |
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char *vname; |
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double val; |
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{ |
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register EPNODE *ep1, *ep2; |
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/* check for quick set */ |
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if ((ep1 = dlookup(vname)) != NULL && ep1->v.kid->type == SYM) { |
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ep2 = ep1->v.kid->sibling; |
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if (ep2->type == NUM) { |
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ep2->v.num = val; |
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ep2->sibling->v.tick = -1; |
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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 = '='; |
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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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ep2 = newnode(); |
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ep2->type = TICK; |
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ep2->v.tick = -1; |
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addekid(ep1, ep2); |
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ep2 = newnode(); |
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ep2->type = NUM; |
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addekid(ep1, ep2); |
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dclear(vname); |
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dpush(ep1); |
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} |
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|
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|
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dclear(name) /* delete all definitions of name */ |
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char *name; |
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{ |
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register EPNODE *ep; |
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|
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while ((ep = dpop(name)) != NULL) |
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epfree(ep); |
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} |
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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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|
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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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#ifdef OUTCHAN |
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chanout() /* set output channels */ |
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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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chanset(ep->v.kid->v.chan, evalue(ep->v.kid->sibling)); |
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|
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} |
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#endif |
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|
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|
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dclearall() /* clear all definitions */ |
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{ |
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register int i; |
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register VARDEF *vp; |
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register EPNODE *ep; |
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|
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for (i = 0; i < NHASH; i++) |
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for (vp = hashtbl[i]; vp != NULL; vp = vp->next) |
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dclear(vp->name); |
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#ifdef OUTCHAN |
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for (ep = outchan; ep != NULL; ep = ep->sibling) |
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epfree(ep); |
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outchan = NULL; |
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#endif |
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} |
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|
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|
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EPNODE * |
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dlookup(name) /* look up a definition */ |
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char *name; |
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{ |
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register VARDEF *vp; |
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|
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if ((vp = varlookup(name)) == NULL) |
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return(NULL); |
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return(vp->def); |
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} |
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|
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|
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VARDEF * |
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varlookup(name) /* look up a variable */ |
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char *name; |
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{ |
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register VARDEF *vp; |
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|
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for (vp = hashtbl[hash(name)]; vp != NULL; vp = vp->next) |
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if (!strcmp(vp->name, name)) |
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return(vp); |
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return(NULL); |
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} |
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|
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|
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VARDEF * |
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varinsert(name) /* get a link to a variable */ |
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char *name; |
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{ |
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register VARDEF *vp; |
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int hv; |
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|
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hv = hash(name); |
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for (vp = hashtbl[hv]; vp != NULL; vp = vp->next) |
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if (!strcmp(vp->name, name)) { |
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vp->nlinks++; |
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return(vp); |
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} |
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vp = (VARDEF *)emalloc(sizeof(VARDEF)); |
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vp->name = savestr(name); |
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vp->nlinks = 1; |
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vp->def = NULL; |
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vp->lib = NULL; |
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vp->next = hashtbl[hv]; |
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hashtbl[hv] = vp; |
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return(vp); |
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} |
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|
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|
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varfree(ln) /* release link to variable */ |
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register VARDEF *ln; |
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{ |
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register VARDEF *vp; |
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int hv; |
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|
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if (--ln->nlinks > 0) |
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return; /* still active */ |
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|
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hv = hash(ln->name); |
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vp = hashtbl[hv]; |
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if (vp == ln) |
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hashtbl[hv] = vp->next; |
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else { |
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while (vp->next != ln) /* must be in list */ |
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vp = vp->next; |
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vp->next = ln->next; |
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} |
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freestr(ln->name); |
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efree((char *)ln); |
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} |
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|
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|
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EPNODE * |
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dfirst() /* return pointer to first definition */ |
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{ |
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htndx = 0; |
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htpos = NULL; |
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#ifdef OUTCHAN |
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ochpos = outchan; |
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#endif |
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return(dnext()); |
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} |
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|
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|
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EPNODE * |
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dnext() /* return pointer to next definition */ |
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{ |
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register EPNODE *ep; |
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|
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while (htndx < NHASH) { |
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if (htpos == NULL) |
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htpos = hashtbl[htndx++]; |
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while (htpos != NULL) { |
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ep = htpos->def; |
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htpos = htpos->next; |
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if (ep != NULL) |
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return(ep); |
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} |
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} |
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#ifdef OUTCHAN |
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if ((ep = ochpos) != NULL) |
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ochpos = ep->sibling; |
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return(ep); |
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#else |
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return(NULL); |
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#endif |
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} |
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|
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|
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EPNODE * |
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dpop(name) /* pop a definition */ |
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char *name; |
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{ |
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register VARDEF *vp; |
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register EPNODE *dp; |
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|
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if ((vp = varlookup(name)) == NULL || vp->def == NULL) |
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return(NULL); |
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dp = vp->def; |
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vp->def = dp->sibling; |
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varfree(vp); |
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return(dp); |
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} |
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|
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|
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dpush(ep) /* push on a definition */ |
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register EPNODE *ep; |
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{ |
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register VARDEF *vp; |
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|
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vp = varinsert(dname(ep)); |
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ep->sibling = vp->def; |
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vp->def = ep; |
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} |
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|
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|
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#ifdef OUTCHAN |
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addchan(sp) /* add an output channel assignment */ |
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EPNODE *sp; |
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{ |
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int ch = sp->v.kid->v.chan; |
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register EPNODE *ep, *epl; |
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|
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for (epl = NULL, ep = outchan; ep != NULL; epl = ep, ep = ep->sibling) |
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if (ep->v.kid->v.chan >= ch) { |
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if (epl != NULL) |
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epl->sibling = sp; |
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else |
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outchan = sp; |
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if (ep->v.kid->v.chan > ch) |
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sp->sibling = ep; |
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else { |
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sp->sibling = ep->sibling; |
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epfree(ep); |
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} |
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return; |
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} |
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if (epl != NULL) |
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epl->sibling = sp; |
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else |
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outchan = sp; |
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sp->sibling = NULL; |
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|
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} |
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#endif |
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|
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|
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loaddefn() /* load next definition */ |
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{ |
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register EPNODE *ep; |
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|
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if (nextc == ';') { /* empty statement */ |
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scan(); |
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return; |
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} |
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#ifdef OUTCHAN |
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if (nextc == '$') { /* channel assignment */ |
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ep = getchan(); |
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addchan(ep); |
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} else |
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#endif |
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{ /* ordinary definition */ |
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ep = getdefn(); |
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#ifdef REDEFW |
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if (dlookup(dname(ep)) != NULL) { |
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dclear(dname(ep)); |
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wputs(dname(ep)); |
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wputs(": redefined\n"); |
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} |
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#else |
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dclear(dname(ep)); |
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#endif |
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dpush(ep); |
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} |
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if (nextc != EOF) { |
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if (nextc != ';') |
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syntax("';' expected"); |
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scan(); |
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} |
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} |
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|
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|
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EPNODE * |
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getdefn() /* A -> SYM = E1 */ |
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/* FUNC(SYM,..) = E1 */ |
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{ |
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register EPNODE *ep1, *ep2; |
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|
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if (!isalpha(nextc)) |
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syntax("illegal variable name"); |
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|
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ep1 = newnode(); |
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ep1->type = SYM; |
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ep1->v.name = savestr(getname()); |
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|
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#ifdef FUNCTION |
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if (nextc == '(') { |
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ep2 = newnode(); |
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ep2->type = FUNC; |
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addekid(ep2, ep1); |
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ep1 = ep2; |
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do { |
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scan(); |
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if (!isalpha(nextc)) |
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syntax("illegal variable name"); |
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ep2 = newnode(); |
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ep2->type = SYM; |
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ep2->v.name = savestr(getname()); |
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addekid(ep1, ep2); |
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} while (nextc == ','); |
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if (nextc != ')') |
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syntax("')' expected"); |
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scan(); |
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curfunc = ep1; |
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} else |
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curfunc = NULL; |
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#endif |
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|
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if (nextc != '=') |
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syntax("'=' expected"); |
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scan(); |
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|
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ep2 = newnode(); |
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ep2->type = '='; |
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addekid(ep2, ep1); |
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addekid(ep2, getE1()); |
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|
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#ifdef FUNCTION |
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if (ep1->type == SYM) |
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#endif |
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{ |
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ep1 = newnode(); |
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ep1->type = TICK; |
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ep1->v.tick = -1; |
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addekid(ep2, ep1); |
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ep1 = newnode(); |
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ep1->type = NUM; |
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addekid(ep2, ep1); |
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} |
| 452 |
|
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return(ep2); |
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} |
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|
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|
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#ifdef OUTCHAN |
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EPNODE * |
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getchan() /* A -> $N = E1 */ |
| 460 |
{ |
| 461 |
register EPNODE *ep1, *ep2; |
| 462 |
|
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if (nextc != '$') |
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syntax("missing '$'"); |
| 465 |
scan(); |
| 466 |
|
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ep1 = newnode(); |
| 468 |
ep1->type = CHAN; |
| 469 |
ep1->v.chan = getinum(); |
| 470 |
|
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if (nextc != '=') |
| 472 |
syntax("'=' expected"); |
| 473 |
scan(); |
| 474 |
|
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ep2 = newnode(); |
| 476 |
ep2->type = '='; |
| 477 |
addekid(ep2, ep1); |
| 478 |
addekid(ep2, getE1()); |
| 479 |
|
| 480 |
return(ep2); |
| 481 |
} |
| 482 |
#endif |
| 483 |
|
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|
| 485 |
|
| 486 |
/* |
| 487 |
* The following routines are for internal use only: |
| 488 |
*/ |
| 489 |
|
| 490 |
|
| 491 |
static double |
| 492 |
dvalue(name, d) /* evaluate a variable */ |
| 493 |
char *name; |
| 494 |
EPNODE *d; |
| 495 |
{ |
| 496 |
register EPNODE *ep1, *ep2; |
| 497 |
|
| 498 |
if (d == NULL || d->v.kid->type != SYM) { |
| 499 |
eputs(name); |
| 500 |
eputs(": undefined variable\n"); |
| 501 |
quit(1); |
| 502 |
} |
| 503 |
ep1 = d->v.kid->sibling; /* get expression */ |
| 504 |
ep2 = ep1->sibling; /* check time */ |
| 505 |
if (ep2->v.tick < 0 || ep2->v.tick < eclock) { |
| 506 |
ep2->v.tick = eclock; |
| 507 |
ep2 = ep2->sibling; |
| 508 |
ep2->v.num = evalue(ep1); /* compute new value */ |
| 509 |
} else |
| 510 |
ep2 = ep2->sibling; /* reuse old value */ |
| 511 |
|
| 512 |
return(ep2->v.num); |
| 513 |
} |
| 514 |
|
| 515 |
|
| 516 |
static int |
| 517 |
hash(s) /* hash a string */ |
| 518 |
register char *s; |
| 519 |
{ |
| 520 |
register int rval = 0; |
| 521 |
|
| 522 |
while (*s) |
| 523 |
rval += *s++; |
| 524 |
|
| 525 |
return(rval % NHASH); |
| 526 |
} |
