gram

c语言编译器

/* Do appropriate processing given the current state.  */
/* Read a lookahead token if we need one and don't already have one.  */
/* yyresume: */

  /* First try to decide what to do without reference to lookahead token.  */

  yyn = yypact[yystate];
  if (yyn == YYFLAG)
    goto yydefault;

  /* Not known => get a lookahead token if don't already have one.  */

  /* yychar is either YYEMPTY or YYEOF
     or a valid token in external form.  */

  if (yychar == YYEMPTY)
    {
#if YYDEBUG != 0
      if (yydebug)
	fprintf(stderr, "Reading a token: ");
#endif
      yychar = YYLEX;
    }

  /* Convert token to internal form (in yychar1) for indexing tables with */

  if (yychar <= 0)		/* This means end of input. */
    {
      yychar1 = 0;
      yychar = YYEOF;		/* Don't call YYLEX any more */

#if YYDEBUG != 0
      if (yydebug)
	fprintf(stderr, "Now at end of input.\n");
#endif
    }
  else
    {
      yychar1 = YYTRANSLATE(yychar);

#if YYDEBUG != 0
      if (yydebug)
	{
	  fprintf (stderr, "Next token is %d (%s", yychar, yytname[yychar1]);
	  /* Give the individual parser a way to print the precise meaning
	     of a token, for further debugging info.  */
#ifdef YYPRINT
	  YYPRINT (stderr, yychar, yylval);
#endif
	  fprintf (stderr, ")\n");
	}
#endif
    }

  yyn += yychar1;
  if (yyn < 0 || yyn > YYLAST || yycheck[yyn] != yychar1)
    goto yydefault;

  yyn = yytable[yyn];

  /* yyn is what to do for this token type in this state.
     Negative => reduce, -yyn is rule number.
     Positive => shift, yyn is new state.
       New state is final state => don't bother to shift,
       just return success.
     0, or most negative number => error.  */

  if (yyn < 0)
    {
      if (yyn == YYFLAG)
	goto yyerrlab;
      yyn = -yyn;
      goto yyreduce;
    }
  else if (yyn == 0)
    goto yyerrlab;

  if (yyn == YYFINAL)
    YYACCEPT;

  /* Shift the lookahead token.  */

#if YYDEBUG != 0
  if (yydebug)
    fprintf(stderr, "Shifting token %d (%s), ", yychar, yytname[yychar1]);
#endif

  /* Discard the token being shifted unless it is eof.  */
  if (yychar != YYEOF)
    yychar = YYEMPTY;

  *++yyvsp = yylval;
#ifdef YYLSP_NEEDED
  *++yylsp = yylloc;
#endif

  /* count tokens shifted since error; after three, turn off error status.  */
  if (yyerrstatus) yyerrstatus--;

  yystate = yyn;
  goto yynewstate;

/* Do the default action for the current state.  */
yydefault:

  yyn = yydefact[yystate];
  if (yyn == 0)
    goto yyerrlab;

/* Do a reduction.  yyn is the number of a rule to reduce with.  */
yyreduce:
  yylen = yyr2[yyn];
  if (yylen > 0)
    yyval = yyvsp[1-yylen]; /* implement default value of the action */

#if YYDEBUG != 0
  if (yydebug)
    {
      int i;

      fprintf (stderr, "Reducing via rule %d (line %d), ",
	       yyn, yyrline[yyn]);

      /* Print the symbols being reduced, and their result.  */
      for (i = yyprhs[yyn]; yyrhs[i] > 0; i++)
	fprintf (stderr, "%s ", yytname[yyrhs[i]]);
      fprintf (stderr, " -> %s\n", yytname[yyr1[yyn]]);
    }
#endif


  switch (yyn) {

case 1:
#line 22 "lburg/gram.y"
{ yylineno = 0; ;
    break;}
case 2:
#line 23 "lburg/gram.y"
{ yylineno = 0; ;
    break;}
case 6:
#line 31 "lburg/gram.y"
{
		if (nonterm(yyvsp[-1].string)->number != 1)
			yyerror("redeclaration of the start symbol\n");
		;
    break;}
case 8:
#line 36 "lburg/gram.y"
{ yyerrok; ;
    break;}
case 10:
#line 40 "lburg/gram.y"
{ term(yyvsp[-2].string, yyvsp[0].n); ;
    break;}
case 12:
#line 44 "lburg/gram.y"
{ rule(yyvsp[-5].string, yyvsp[-3].tree, yyvsp[-2].string, yyvsp[-1].string); ;
    break;}
case 14:
#line 46 "lburg/gram.y"
{ yyerrok; ;
    break;}
case 15:
#line 49 "lburg/gram.y"
{ nonterm(yyval.string = yyvsp[0].string); ;
    break;}
case 16:
#line 52 "lburg/gram.y"
{ yyval.tree = tree(yyvsp[0].string,  0,  0); ;
    break;}
case 17:
#line 53 "lburg/gram.y"
{ yyval.tree = tree(yyvsp[-3].string, yyvsp[-1].tree,  0); ;
    break;}
case 18:
#line 54 "lburg/gram.y"
{ yyval.tree = tree(yyvsp[-5].string, yyvsp[-3].tree, yyvsp[-1].tree); ;
    break;}
case 19:
#line 57 "lburg/gram.y"
{ if (*yyvsp[0].string == 0) yyval.string = "0"; ;
    break;}
}
   /* the action file gets copied in in place of this dollarsign */
#line 487 "bison.simple"

  yyvsp -= yylen;
  yyssp -= yylen;
#ifdef YYLSP_NEEDED
  yylsp -= yylen;
#endif

#if YYDEBUG != 0
  if (yydebug)
    {
      short *ssp1 = yyss - 1;
      fprintf (stderr, "state stack now");
      while (ssp1 != yyssp)
	fprintf (stderr, " %d", *++ssp1);
      fprintf (stderr, "\n");
    }
#endif

  *++yyvsp = yyval;

#ifdef YYLSP_NEEDED
  yylsp++;
  if (yylen == 0)
    {
      yylsp->first_line = yylloc.first_line;
      yylsp->first_column = yylloc.first_column;
      yylsp->last_line = (yylsp-1)->last_line;
      yylsp->last_column = (yylsp-1)->last_column;
      yylsp->text = 0;
    }
  else
    {
      yylsp->last_line = (yylsp+yylen-1)->last_line;
      yylsp->last_column = (yylsp+yylen-1)->last_column;
    }
#endif

  /* Now "shift" the result of the reduction.
     Determine what state that goes to,
     based on the state we popped back to
     and the rule number reduced by.  */

  yyn = yyr1[yyn];

  yystate = yypgoto[yyn - YYNTBASE] + *yyssp;
  if (yystate >= 0 && yystate <= YYLAST && yycheck[yystate] == *yyssp)
    yystate = yytable[yystate];
  else
    yystate = yydefgoto[yyn - YYNTBASE];

  goto yynewstate;

yyerrlab:   /* here on detecting error */

  if (! yyerrstatus)
    /* If not already recovering from an error, report this error.  */
    {
      ++yynerrs;

#ifdef YYERROR_VERBOSE
      yyn = yypact[yystate];

      if (yyn > YYFLAG && yyn < YYLAST)
	{
	  int size = 0;
	  char *msg;
	  int x, count;

	  count = 0;
	  /* Start X at -yyn if nec to avoid negative indexes in yycheck.  */
	  for (x = (yyn < 0 ? -yyn : 0);
	       x < (sizeof(yytname) / sizeof(char *)); x++)
	    if (yycheck[x + yyn] == x)
	      size += strlen(yytname[x]) + 15, count++;
	  msg = (char *) malloc(size + 15);
	  if (msg != 0)
	    {
	      strcpy(msg, "parse error");

	      if (count < 5)
		{
		  count = 0;
		  for (x = (yyn < 0 ? -yyn : 0);
		       x < (sizeof(yytname) / sizeof(char *)); x++)
		    if (yycheck[x + yyn] == x)
		      {
			strcat(msg, count == 0 ? ", expecting `" : " or `");
			strcat(msg, yytname[x]);
			strcat(msg, "'");
			count++;
		      }
		}
	      yyerror(msg);
	      free(msg);
	    }
	  else
	    yyerror ("parse error; also virtual memory exceeded");
	}
      else
#endif /* YYERROR_VERBOSE */
	yyerror("parse error");
    }

  goto yyerrlab1;
yyerrlab1:   /* here on error raised explicitly by an action */

  if (yyerrstatus == 3)
    {
      /* if just tried and failed to reuse lookahead token after an error, discard it.  */

      /* return failure if at end of input */
      if (yychar == YYEOF)
	YYABORT;

#if YYDEBUG != 0
      if (yydebug)
	fprintf(stderr, "Discarding token %d (%s).\n", yychar, yytname[yychar1]);
#endif

      yychar = YYEMPTY;
    }

  /* Else will try to reuse lookahead token
     after shifting the error token.  */

  yyerrstatus = 3;		/* Each real token shifted decrements this */

  goto yyerrhandle;

yyerrdefault:  /* current state does not do anything special for the error token. */

#if 0
  /* This is wrong; only states that explicitly want error tokens
     should shift them.  */
  yyn = yydefact[yystate];  /* If its default is to accept any token, ok.  Otherwise pop it.*/
  if (yyn) goto yydefault;
#endif

yyerrpop:   /* pop the current state because it cannot handle the error token */

  if (yyssp == yyss) YYABORT;
  yyvsp--;
  yystate = *--yyssp;
#ifdef YYLSP_NEEDED
  yylsp--;
#endif

#if YYDEBUG != 0
  if (yydebug)
    {
      short *ssp1 = yyss - 1;
      fprintf (stderr, "Error: state stack now");
      while (ssp1 != yyssp)
	fprintf (stderr, " %d", *++ssp1);
      fprintf (stderr, "\n");
    }
#endif

yyerrhandle:

  yyn = yypact[yystate];
  if (yyn == YYFLAG)
    goto yyerrdefault;

  yyn += YYTERROR;
  if (yyn < 0 || yyn > YYLAST || yycheck[yyn] != YYTERROR)
    goto yyerrdefault;

  yyn = yytable[yyn];
  if (yyn < 0)
    {
      if (yyn == YYFLAG)
	goto yyerrpop;
      yyn = -yyn;
      goto yyreduce;
    }
  else if (yyn == 0)
    goto yyerrpop;

  if (yyn == YYFINAL)
    YYACCEPT;

#if YYDEBUG != 0
  if (yydebug)
    fprintf(stderr, "Shifting error token, ");
#endif

  *++yyvsp = yylval;
#ifdef YYLSP_NEEDED
  *++yylsp = yylloc;
#endif

  yystate = yyn;
  goto yynewstate;
}
#line 59 "lburg/gram.y"

#include <assert.h>
#include <stdarg.h>
#include <ctype.h>
#include <string.h>
#include <limits.h>

int errcnt = 0;
FILE *infp = NULL;
FILE *outfp = NULL;
static char buf[BUFSIZ], *bp = buf;
static int ppercent = 0;
static int code = 0;

static int get(void) {
	if (*bp == 0) {
		bp = buf;
		*bp = 0;
		if (fgets(buf, sizeof buf, infp) == NULL)
			return EOF;
		yylineno++;
		while (buf[0] == '%' && buf[1] == '{' && buf[2] == '\n') {
			for (;;) {
				if (fgets(buf, sizeof buf, infp) == NULL) {
					yywarn("unterminated %{...%}\n");
					return EOF;
				}
				yylineno++;
				if (strcmp(buf, "%}\n") == 0)
					break;
				fputs(buf, outfp);
			}
			if (fgets(buf, sizeof buf, infp) == NULL)
				return EOF;
			yylineno++;
		}
	}
	return *bp++;
}

void yyerror(char *fmt, ...) {
	va_list ap;

	va_start(ap, fmt);
	if (yylineno > 0)
		fprintf(stderr, "line %d: ", yylineno);
	vfprintf(stderr, fmt, ap);
	if (fmt[strlen(fmt)-1] != '\n')
		 fprintf(stderr, "\n");
	errcnt++;
	va_end(ap);
}

int yylex(void) {
	int c;

	if (code) {
		char *p;
		bp += strspn(bp, " \t\f");
		p = strchr(bp, '\n');
		if (p == NULL)
			p = strchr(bp, '\n');
		while (p > bp && isspace(p[-1]))
			p--;
		yylval.string = alloc(p - bp + 1);
		strncpy(yylval.string, bp, p - bp);
		yylval.string[p - bp] = 0;
		bp = p;
		code--;
		return CODE;
	}
	while ((c = get()) != EOF) {
		switch (c) {
		case ' ': case '\f': case '\t':
			continue;
		case '\n':
		case '(': case ')': case ',':
		case ':': case '=':
			return c;
		}
		if (c == '%' && *bp == '%') {
			bp++;
			return ppercent++ ? 0 : PPERCENT;
		} else if (c == '%' && strncmp(bp, "term", 4) == 0
		&& isspace(bp[4])) {
			bp += 4;
			return TERMINAL;
		} else if (c == '%' && strncmp(bp, "start", 5) == 0
		&& isspace(bp[5])) {
			bp += 5;
			return START;
		} else if (c == '"') {
			char *p = strchr(bp, '"');
			if (p == NULL) {
				yyerror("missing \" in assembler template\n");
				p = strchr(bp, '\n');
				if (p == NULL)
					p = strchr(bp, '\0');
			}
			assert(p);
			yylval.string = alloc(p - bp + 1);
			strncpy(yylval.string, bp, p - bp);
			yylval.string[p - bp] = 0;
			bp = *p == '"' ? p + 1 : p;
			code++;
			return TEMPLATE;
		} else if (isdigit(c)) {
			int n = 0;
			do {
				int d = c - '0';
				if (n > (INT_MAX - d)/10)
					yyerror("integer greater than %d\n", INT_MAX);
				else
					n = 10*n + d;
				c = get();
			} while (c != EOF && isdigit(c));
			bp--;
			yylval.n = n;
			return INT;
		} else if (isalpha(c)) {
			char *p = bp - 1;
			while (isalpha(*bp) || isdigit(*bp) || *bp == '_')
				bp++;
			yylval.string = alloc(bp - p + 1);
			strncpy(yylval.string, p, bp - p);
			yylval.string[bp - p] = 0;
			return ID;
		} else if (isprint(c))
			yyerror("invalid character `%c'\n", c);
		else
			yyerror("invalid character `\\%03o'\n", (unsigned char)c);
	}
	return 0;
}

void yywarn(char *fmt, ...) {
	va_list ap;

	va_start(ap, fmt);
	if (yylineno > 0)
		fprintf(stderr, "line %d: ", yylineno);
	fprintf(stderr, "warning: ");
	vfprintf(stderr, fmt, ap);
}