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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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* Compute data values using expression parser |
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* |
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* 7/1/85 Greg Ward |
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* |
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* 11/11/85 Made channel input conditional with (INCHAN) compiles. |
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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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* 1/29/87 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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|
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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 <errno.h> |
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|
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#include "calcomp.h" |
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|
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#define MAXLINE 256 /* maximum line length */ |
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#define MAXWORD 64 /* maximum word length */ |
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|
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#define newnode() (EPNODE *)ecalloc(1, sizeof(EPNODE)) |
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|
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#define isid(c) (isalnum(c) || (c) == '_' || (c) == '.') |
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|
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#define isdecimal(c) (isdigit(c) || (c) == '.') |
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|
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extern double atof(), pow(); |
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extern char *fgets(), *savestr(); |
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extern char *emalloc(), *ecalloc(); |
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extern EPNODE *curfunc; |
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extern double efunc(), evariable(); |
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static double euminus(), echannel(), eargument(), enumber(); |
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static double eadd(), esubtr(), emult(), edivi(), epow(); |
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static double ebotch(); |
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extern int errno; |
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|
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int nextc; /* lookahead character */ |
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|
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double (*eoper[])() = { /* expression operations */ |
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ebotch, |
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#ifdef VARIABLE |
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evariable, |
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#else |
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ebotch, |
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#endif |
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enumber, |
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euminus, |
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#ifdef INCHAN |
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echannel, |
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#else |
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ebotch, |
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#endif |
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#ifdef FUNCTION |
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efunc, |
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eargument, |
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#else |
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ebotch, |
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ebotch, |
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#endif |
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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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0,0,0,0,0,0,0,0,0,0,0,0,0, |
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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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|
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static char *infile; /* input file name */ |
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static FILE *infp; /* input file pointer */ |
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static char *linbuf; /* line buffer */ |
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static int linepos; /* position in buffer */ |
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|
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|
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EPNODE * |
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eparse(expr) /* parse an expression string */ |
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char *expr; |
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{ |
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EPNODE *ep; |
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|
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initstr(NULL, expr); |
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#if defined(VARIABLE) && defined(FUNCTION) |
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curfunc = NULL; |
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#endif |
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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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|
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|
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double |
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eval(expr) /* evaluate an expression string */ |
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char *expr; |
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{ |
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register EPNODE *ep; |
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double rval; |
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|
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ep = eparse(expr); |
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rval = evalue(ep); |
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epfree(ep); |
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return(rval); |
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} |
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|
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|
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epfree(epar) /* free a parse tree */ |
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register EPNODE *epar; |
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{ |
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register EPNODE *ep; |
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|
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switch (epar->type) { |
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|
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#if defined(VARIABLE) || defined(FUNCTION) |
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case VAR: |
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varfree(epar->v.ln); |
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break; |
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#endif |
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|
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case SYM: |
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freestr(epar->v.name); |
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break; |
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|
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case NUM: |
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case CHAN: |
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case ARG: |
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case TICK: |
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break; |
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|
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default: |
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for (ep = epar->v.kid; ep != NULL; ep = ep->sibling) |
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epfree(ep); |
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break; |
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|
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} |
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|
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efree((char *)epar); |
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} |
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|
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/* the following used to be a switch */ |
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#ifdef FUNCTION |
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static double |
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eargument(ep) |
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EPNODE *ep; |
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{ |
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return(argument(ep->v.chan)); |
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} |
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#endif |
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|
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static double |
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enumber(ep) |
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EPNODE *ep; |
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{ |
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return(ep->v.num); |
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} |
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|
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static double |
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euminus(ep) |
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EPNODE *ep; |
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{ |
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register EPNODE *ep1 = ep->v.kid; |
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|
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return(-evalue(ep1)); |
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} |
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|
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#ifdef INCHAN |
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static double |
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echannel(ep) |
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EPNODE *ep; |
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{ |
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return(chanvalue(ep->v.chan)); |
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} |
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#endif |
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|
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static double |
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eadd(ep) |
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EPNODE *ep; |
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{ |
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register EPNODE *ep1 = ep->v.kid; |
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|
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return(evalue(ep1) + evalue(ep1->sibling)); |
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} |
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|
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static double |
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esubtr(ep) |
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EPNODE *ep; |
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{ |
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register EPNODE *ep1 = ep->v.kid; |
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|
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return(evalue(ep1) - evalue(ep1->sibling)); |
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} |
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|
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static double |
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emult(ep) |
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EPNODE *ep; |
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{ |
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register EPNODE *ep1 = ep->v.kid; |
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|
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return(evalue(ep1) * evalue(ep1->sibling)); |
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} |
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|
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static double |
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edivi(ep) |
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EPNODE *ep; |
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{ |
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register EPNODE *ep1 = ep->v.kid; |
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double d; |
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|
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d = evalue(ep1->sibling); |
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if (d == 0.0) { |
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wputs("Division by zero\n"); |
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errno = ERANGE; |
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return(0.0); |
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} |
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return(evalue(ep1) / d); |
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} |
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|
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static double |
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epow(ep) |
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EPNODE *ep; |
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{ |
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register EPNODE *ep1 = ep->v.kid; |
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double d; |
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int lasterrno; |
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|
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lasterrno = errno; |
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errno = 0; |
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d = pow(evalue(ep1), evalue(ep1->sibling)); |
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#ifdef IEEE |
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if (!finite(d)) |
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errno = EDOM; |
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#endif |
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if (errno) { |
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wputs("Illegal power\n"); |
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return(0.0); |
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} |
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errno = lasterrno; |
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return(d); |
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} |
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|
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static double |
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ebotch(ep) |
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EPNODE *ep; |
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{ |
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eputs("Bad expression!\n"); |
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quit(1); |
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} |
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|
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|
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EPNODE * |
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ekid(ep, n) /* return pointer to a node's nth kid */ |
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register EPNODE *ep; |
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register int n; |
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{ |
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|
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for (ep = ep->v.kid; ep != NULL; ep = ep->sibling) |
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if (--n < 0) |
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break; |
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|
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return(ep); |
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} |
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|
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|
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int |
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nekids(ep) /* return # of kids for node ep */ |
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register EPNODE *ep; |
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{ |
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register int n = 0; |
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|
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for (ep = ep->v.kid; ep != NULL; ep = ep->sibling) |
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n++; |
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|
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return(n); |
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} |
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|
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|
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initfile(file, fp) /* prepare input file */ |
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char *file; |
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FILE *fp; |
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{ |
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static char inpbuf[MAXLINE]; |
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|
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infile = file; |
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infp = fp; |
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linbuf = inpbuf; |
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linepos = 0; |
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inpbuf[0] = '\0'; |
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scan(); |
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} |
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|
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|
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initstr(file, s) /* prepare input string */ |
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char *file; |
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char *s; |
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{ |
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infile = file; |
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infp = NULL; |
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linbuf = s; |
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linepos = 0; |
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scan(); |
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} |
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|
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|
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scan() /* scan next character */ |
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{ |
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do { |
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if (linbuf[linepos] == '\0') |
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if (infp == NULL || fgets(linbuf, MAXLINE, infp) == NULL) |
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nextc = EOF; |
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else { |
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nextc = linbuf[0]; |
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linepos = 1; |
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} |
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else |
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nextc = linbuf[linepos++]; |
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if (nextc == '{') { |
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scan(); |
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while (nextc != '}') |
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if (nextc == EOF) |
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syntax("'}' expected"); |
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else |
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scan(); |
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scan(); |
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} |
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} while (isspace(nextc)); |
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} |
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|
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|
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syntax(err) /* report syntax error and quit */ |
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char *err; |
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{ |
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register int i; |
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|
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eputs(linbuf); |
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if (linbuf[strlen(linbuf)-1] != '\n') |
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eputs("\n"); |
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for (i = 0; i < linepos-1; i++) |
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eputs(linbuf[i] == '\t' ? "\t" : " "); |
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eputs("^ "); |
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if (infile != NULL) { |
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eputs(infile); |
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eputs(": "); |
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} |
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eputs(err); |
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eputs("\n"); |
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quit(1); |
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} |
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|
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|
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addekid(ep, ekid) /* add a child to ep */ |
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register EPNODE *ep; |
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EPNODE *ekid; |
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{ |
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if (ep->v.kid == NULL) |
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ep->v.kid = ekid; |
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else { |
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for (ep = ep->v.kid; ep->sibling != NULL; ep = ep->sibling) |
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; |
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ep->sibling = ekid; |
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} |
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ekid->sibling = NULL; |
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} |
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|
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|
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char * |
384 |
getname() /* scan an identifier */ |
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{ |
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static char str[MAXWORD+1]; |
387 |
register int i; |
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|
389 |
for (i = 0; i < MAXWORD && isid(nextc); i++, scan()) |
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str[i] = nextc; |
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str[i] = '\0'; |
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|
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return(str); |
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} |
395 |
|
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|
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int |
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getinum() /* scan a positive integer */ |
399 |
{ |
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register int n; |
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|
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n = 0; |
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while (isdigit(nextc)) { |
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n = n * 10 + nextc - '0'; |
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scan(); |
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} |
407 |
return(n); |
408 |
} |
409 |
|
410 |
|
411 |
double |
412 |
getnum() /* scan a positive float */ |
413 |
{ |
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register int i; |
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char str[MAXWORD+1]; |
416 |
|
417 |
i = 0; |
418 |
while (isdigit(nextc) && i < MAXWORD) { |
419 |
str[i++] = nextc; |
420 |
scan(); |
421 |
} |
422 |
if (nextc == '.' && i < MAXWORD) { |
423 |
str[i++] = nextc; |
424 |
scan(); |
425 |
while (isdigit(nextc) && i < MAXWORD) { |
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str[i++] = nextc; |
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scan(); |
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} |
429 |
} |
430 |
if ((nextc == 'e' || nextc == 'E') && i < MAXWORD) { |
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str[i++] = nextc; |
432 |
scan(); |
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if ((nextc == '-' || nextc == '+') && i < MAXWORD) { |
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str[i++] = nextc; |
435 |
scan(); |
436 |
} |
437 |
while (isdigit(nextc) && i < MAXWORD) { |
438 |
str[i++] = nextc; |
439 |
scan(); |
440 |
} |
441 |
} |
442 |
str[i] = '\0'; |
443 |
|
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return(atof(str)); |
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} |
446 |
|
447 |
|
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EPNODE * |
449 |
getE1() /* E1 -> E1 ADDOP E2 */ |
450 |
/* E2 */ |
451 |
{ |
452 |
register EPNODE *ep1, *ep2; |
453 |
|
454 |
ep1 = getE2(); |
455 |
while (nextc == '+' || nextc == '-') { |
456 |
ep2 = newnode(); |
457 |
ep2->type = nextc; |
458 |
scan(); |
459 |
addekid(ep2, ep1); |
460 |
addekid(ep2, getE2()); |
461 |
#ifdef RCONST |
462 |
if (ep1->type == NUM && ep1->sibling->type == NUM) |
463 |
ep2 = rconst(ep2); |
464 |
#endif |
465 |
ep1 = ep2; |
466 |
} |
467 |
return(ep1); |
468 |
} |
469 |
|
470 |
|
471 |
EPNODE * |
472 |
getE2() /* E2 -> E2 MULOP E3 */ |
473 |
/* E3 */ |
474 |
{ |
475 |
register EPNODE *ep1, *ep2; |
476 |
|
477 |
ep1 = getE3(); |
478 |
while (nextc == '*' || nextc == '/') { |
479 |
ep2 = newnode(); |
480 |
ep2->type = nextc; |
481 |
scan(); |
482 |
addekid(ep2, ep1); |
483 |
addekid(ep2, getE3()); |
484 |
#ifdef RCONST |
485 |
if (ep1->type == NUM && ep1->sibling->type == NUM) |
486 |
ep2 = rconst(ep2); |
487 |
#endif |
488 |
ep1 = ep2; |
489 |
} |
490 |
return(ep1); |
491 |
} |
492 |
|
493 |
|
494 |
EPNODE * |
495 |
getE3() /* E3 -> E3 ^ E4 */ |
496 |
/* E4 */ |
497 |
{ |
498 |
register EPNODE *ep1, *ep2; |
499 |
|
500 |
ep1 = getE4(); |
501 |
while (nextc == '^') { |
502 |
ep2 = newnode(); |
503 |
ep2->type = nextc; |
504 |
scan(); |
505 |
addekid(ep2, ep1); |
506 |
addekid(ep2, getE4()); |
507 |
#ifdef RCONST |
508 |
if (ep1->type == NUM && ep1->sibling->type == NUM) |
509 |
ep2 = rconst(ep2); |
510 |
#endif |
511 |
ep1 = ep2; |
512 |
} |
513 |
return(ep1); |
514 |
} |
515 |
|
516 |
|
517 |
EPNODE * |
518 |
getE4() /* E4 -> ADDOP E5 */ |
519 |
/* E5 */ |
520 |
{ |
521 |
register EPNODE *ep1, *ep2; |
522 |
|
523 |
if (nextc == '-') { |
524 |
scan(); |
525 |
ep2 = getE5(); |
526 |
if (ep2->type == NUM) { |
527 |
ep2->v.num = -ep2->v.num; |
528 |
return(ep2); |
529 |
} |
530 |
ep1 = newnode(); |
531 |
ep1->type = UMINUS; |
532 |
addekid(ep1, ep2); |
533 |
return(ep1); |
534 |
} |
535 |
if (nextc == '+') |
536 |
scan(); |
537 |
return(getE5()); |
538 |
} |
539 |
|
540 |
|
541 |
EPNODE * |
542 |
getE5() /* E5 -> (E1) */ |
543 |
/* VAR */ |
544 |
/* NUM */ |
545 |
/* $N */ |
546 |
/* FUNC(E1,..) */ |
547 |
/* ARG */ |
548 |
{ |
549 |
int i; |
550 |
register EPNODE *ep1, *ep2; |
551 |
|
552 |
if (nextc == '(') { |
553 |
scan(); |
554 |
ep1 = getE1(); |
555 |
if (nextc != ')') |
556 |
syntax("')' expected"); |
557 |
scan(); |
558 |
return(ep1); |
559 |
} |
560 |
|
561 |
#ifdef INCHAN |
562 |
if (nextc == '$') { |
563 |
scan(); |
564 |
ep1 = newnode(); |
565 |
ep1->type = CHAN; |
566 |
ep1->v.chan = getinum(); |
567 |
return(ep1); |
568 |
} |
569 |
#endif |
570 |
|
571 |
#if defined(VARIABLE) || defined(FUNCTION) |
572 |
if (isalpha(nextc)) { |
573 |
ep1 = newnode(); |
574 |
ep1->type = VAR; |
575 |
ep1->v.ln = varinsert(getname()); |
576 |
|
577 |
#if defined(VARIABLE) && defined(FUNCTION) |
578 |
if (curfunc != NULL) |
579 |
for (i = 1, ep2 = curfunc->v.kid->sibling; |
580 |
ep2 != NULL; i++, ep2 = ep2->sibling) |
581 |
if (!strcmp(ep2->v.name, ep1->v.ln->name)) { |
582 |
epfree(ep1); |
583 |
ep1 = newnode(); |
584 |
ep1->type = ARG; |
585 |
ep1->v.chan = i; |
586 |
break; |
587 |
} |
588 |
#endif |
589 |
#ifdef FUNCTION |
590 |
if (nextc == '(') { |
591 |
ep2 = newnode(); |
592 |
ep2->type = FUNC; |
593 |
addekid(ep2, ep1); |
594 |
ep1 = ep2; |
595 |
do { |
596 |
scan(); |
597 |
addekid(ep1, getE1()); |
598 |
} while (nextc == ','); |
599 |
if (nextc != ')') |
600 |
syntax("')' expected"); |
601 |
scan(); |
602 |
} |
603 |
#ifndef VARIABLE |
604 |
else |
605 |
syntax("'(' expected"); |
606 |
#endif |
607 |
#endif |
608 |
return(ep1); |
609 |
} |
610 |
#endif |
611 |
|
612 |
if (isdecimal(nextc)) { |
613 |
ep1 = newnode(); |
614 |
ep1->type = NUM; |
615 |
ep1->v.num = getnum(); |
616 |
return(ep1); |
617 |
} |
618 |
syntax("unexpected character"); |
619 |
} |
620 |
|
621 |
|
622 |
#ifdef RCONST |
623 |
EPNODE * |
624 |
rconst(epar) /* reduce a constant expression */ |
625 |
register EPNODE *epar; |
626 |
{ |
627 |
register EPNODE *ep; |
628 |
|
629 |
ep = newnode(); |
630 |
ep->type = NUM; |
631 |
errno = 0; |
632 |
ep->v.num = evalue(epar); |
633 |
if (errno) |
634 |
syntax("bad constant expression"); |
635 |
epfree(epar); |
636 |
|
637 |
return(ep); |
638 |
} |
639 |
#endif |