BSD 4_1c_2 release

[unix-history] / usr / src / ucb / pascal / src / yylex.c

/* Copyright (c) 1979 Regents of the University of California */

static char sccsid[] = "@(#)yylex.c 1.3 8/29/82";

#include "whoami.h"
#include "0.h"
#include "yy.h"

/*
* Scanner
*/
int     yylacnt;

#define YYLASIZ 10

struct  yytok Yla[YYLASIZ];

unyylex(y)
       struct yylex *y;
{

       if (yylacnt == YYLASIZ)
               panic("unyylex");
       copy(&Yla[yylacnt], y, sizeof Yla[0]);
       yylacnt++;

}

yylex()
{
       register c;
       register **ip;
       register char *cp;
       int f;
       char delim;

       if (yylacnt != 0) {
               yylacnt--;
               copy(&Y, &Yla[yylacnt], sizeof Y);
               return (yychar);
       }
       if (c = yysavc)
               yysavc = 0;
       else
               c = readch();
#ifdef PXP
       yytokcnt++;
#endif

next:
       /*
        * skip white space
        */
#ifdef PXP
       yywhcnt = 0;
#endif
       while (c == ' ' || c == '\t') {
#ifdef PXP
               if (c == '\t')
                       yywhcnt++;
               yywhcnt++;
#endif
               c = readch();
       }
       yyecol = yycol;
       yyeline = yyline;
       yyefile = filename;
       yyeseqid = yyseqid;
       yyseekp = yylinpt;
       cp = token;
       yylval = yyline;
       switch (c) {
               case 'a': case 'b': case 'c': case 'd': case 'e': case 'f': case 'g': 
               case 'h': case 'i': case 'j': case 'k': case 'l': case 'm': case 'n': 
               case 'o': case 'p': case 'q': case 'r': case 's': case 't': case 'u': 
               case 'v': case 'w': case 'x': case 'y': case 'z': 
               case 'A': case 'B': case 'C': case 'D': case 'E': case 'F': case 'G': 
               case 'H': case 'I': case 'J': case 'K': case 'L': case 'M': case 'N': 
               case 'O': case 'P': case 'Q': case 'R': case 'S': case 'T': case 'U': 
               case 'V': case 'W': case 'X': case 'Y': case 'Z': 
                       do {
                               *cp++ = c;
                               c = readch();
                       } while (alph(c) || digit(c));
                       *cp = 0;
                       if (opt('s'))
                               for (cp = token; *cp; cp++)
                                       if (*cp >= 'A' && *cp <= 'Z') {
                                               *cp |= ' ';
                                       }
                       yysavc = c;
                       ip = hash(0, 1);
                       if (*ip < yykey || *ip >= lastkey) {
                               yylval = *ip;
                               return (YID);
                       }
                       yylval = yyline;
                       /*
                        * For keywords
                        * the lexical token
                        * is magically retrieved
                        * from the keyword table.
                        */
                       return ((*ip)[1]);
               case '0': case '1': case '2': case '3': case '4':
               case '5': case '6': case '7': case '8': case '9':
                       f = 0;
                       do {
                               *cp++ = c;
                               c = readch();
                       } while (digit(c));
                       if (c == 'b' || c == 'B') {
                               /*
                                * nonstandard - octal constants
                                */
                               if (opt('s')) {
                                       standard();
                                       yerror("Octal constants are non-standard");
                               }
                               *cp = 0;
                               yylval = copystr(token);
                               return (YBINT);
                       }
                       if (c == '.') {
                               c = readch();
                               if (c == '.') {
                                       *cp = 0;
                                       yysavc = YDOTDOT;
                                       yylval = copystr(token);
                                       return (YINT);
                               }
infpnumb:
                               f++;
                               *cp++ = '.';
                               if (!digit(c)) {
                                       yyset();
                                       recovered();
                                       yerror("Digits required after decimal point");
                                       *cp++ = '0';
                               } else
                                       while (digit(c)) {
                                               *cp++ = c;
                                               c = readch();
                                       }
                       }
                       if (c == 'e' || c == 'E') {
                               f++;
                               *cp++ = c;
                               if ((c = yysavc) == 0)
                                       c = readch();
                               if (c == '+' || c == '-') {
                                       *cp++ = c;
                                       c = readch();
                               }
                               if (!digit(c)) {
                                       yyset();
                                       yerror("Digits required in exponent");
                                       *cp++ = '0';
                               } else
                                       while (digit(c)) {
                                               *cp++ = c;
                                               c = readch();
                                       }
                       }
                       *cp = 0;
                       yysavc = c;
                       yylval = copystr(token);
                       if (f)
                               return (YNUMB);
                       return (YINT);
               case '"':
               case '`':
               case '#':
                       if (!any(bufp + 1, c))
                               goto illch;
                       if (!dquote) {
                               recovered();
                               dquote++;
                               yerror("Character/string delimiter is '");
                       }
               case '\'':
                       delim = c;
                       do {
                               do {
                                       c = readch();
                                       if (c == '\n') {
                                               yerror("Unmatched %c for string", delim);
                                               if (cp == token)
                                                       *cp++ = ' ', cp++;
                                               break;
                                       }
                                       *cp++ = c;
                               } while (c != delim);
                               c = readch();
                       } while (c == delim);
                       *--cp = 0;
                       if (cp == token) {
                               yerror("Null string not allowed");
                               *cp++ = ' ';
                               *cp++ = 0;
                       }
                       yysavc = c;
                       yylval = copystr(token);
                       return (YSTRING);
               case '.':
                       c = readch();
                       if (c == '.')
                               return (YDOTDOT);
                       if (digit(c)) {
                               recovered();
                               yerror("Digits required before decimal point");
                               *cp++ = '0';
                               goto infpnumb;
                       }
                       yysavc = c;
                       return ('.');
               case '{':
                       /*
                        * { ... } comment
                        */
#ifdef PXP
                       getcm(c);
#endif
#ifdef PI
                       c = options();
                       while (c != '}') {
                               if (c <= 0)
                                       goto nonterm;
                               if (c == '{') {
                                       warning();
                                       yyset();
                                       yerror("{ in a { ... } comment");
                               }
                               c = readch();
                       }
#endif
                       c = readch();
                       goto next;
               case '(':
                       if ((c = readch()) == '*') {
                               /*
                                * (* ... *) comment
                                */
#ifdef PXP
                               getcm(c);
                               c = readch();
                               goto next;
#endif
#ifdef PI
                               c = options();
                               for (;;) {
                                       if (c < 0) {
nonterm:
                                               yerror("Comment does not terminate - QUIT");
                                               pexit(ERRS);
                                       }
                                       if (c == '(' && (c = readch()) == '*') {
                                               warning();
                                               yyset();
                                               yerror("(* in a (* ... *) comment");
                                       }
                                       if (c == '*') {
                                               if ((c = readch()) != ')')
                                                       continue;
                                               c = readch();
                                               goto next;
                                       }
                                       c = readch();
                               }
#endif
                       }
                       yysavc = c;
                       c = '(';
               case ';':
               case ',':
               case ':':
               case '=':
               case '*':
               case '+':
               case '/':
               case '-':
               case ')':
               case '[':
               case ']':
               case '<':
               case '>':
               case '^':
                       return (c);
               case '~':
               case '|':
               case '&':
                       if ( opt('s') ) {
                           yyset();
                           standard();
                           yerror("%c is non-standard", c);
                       }
                       return c;
               default:
                       switch (c) {
                               case YDOTDOT:
                                       return (c);
                               case '\n':
                                       c = readch();
#ifdef PXP
                                       yytokcnt++;
#endif
                                       goto next;
                               case '\f':
                                       c = readch();
                                       goto next;
                       }
                       if (c <= 0)
                               return (YEOF);
illch:
                       do
                               yysavc = readch();
                       while (yysavc == c);
                       yylval = c;
                       return (YILLCH);
       }
}

yyset()
{

       yyecol = yycol;
       yyeline = yyline;
       yyefile = filename;
       yyseekp = yylinpt;
}

/*
* Setuflg trims the current
* input line to at most 72 chars
* for the u option.
*/
setuflg()
{

       if (charbuf[71] != '\n') {
               charbuf[72] = '\n';
               charbuf[73] = 0;
       }
}