xref: /original-bsd/usr.bin/pascal/src/yy.h (revision 50877dca)
1 /*-
2  * Copyright (c) 1980, 1993
3  *	The Regents of the University of California.  All rights reserved.
4  *
5  * %sccs.include.redist.c%
6  *
7  *	@(#)yy.h	8.1 (Berkeley) 06/06/93
8  */
9 
10 #include "y.tab.h"
11 #undef CBSIZE	/* from paramsys/param.h */
12 /*
13  * INPUT/OUTPUT
14  */
15 
16 /*
17  * The buffer for the input file is normally "ibuf".
18  * When files are included, however, this may be
19  * pushed down in the stack of currently active
20  * files. For this reason, the pointer ibp always
21  * references the i/o buffer of the current input file.
22  */
23 FILE		*ibuf, *ibp;
24 
25 /*
26  * Line and token buffers.  Charbuf is the character buffer for
27  * input lines, token the buffer for tokens returned
28  * by the scanner.  CBSIZE defines the maximum line
29  * length allowed on input and is doubtless too small.
30  * The token buffer should be a local array in yylex.
31  */
32 #ifdef ADDR16
33 #define CBSIZE 161
34 #endif ADDR16
35 #ifdef ADDR32
36 #define CBSIZE 1024
37 #endif ADDR32
38 
39 char	charbuf[CBSIZE], *bufp, token[CBSIZE];
40 
41 #define digit(c)	(c >= '0' && c <= '9')
42 #define alph(c)		((c >= 'a' && c <= 'z') || (c >= 'A' && c <= 'Z'))
43 
44 /*
45  * Flag to prevent reprinting current line after
46  * an error.
47  */
48 char	yyprtd;
49 
50 /*
51  * The following variables are maintained by
52  * the scanner in the file lex and used in scanning
53  * and in parsing.
54  *
55  * The variable yychar is the current scanner character.
56  * Currently, the scanner must be called as
57  *	yychar = yylex()
58  * even though it should set yychar itself.
59  * Yychar has value YEOF at end of file, and negative value if
60  * there is no yychar, e.g. after a shift in the parser.
61  *
62  * The variable yycol is the current column in the line whose number
63  * is given by yyline.  Yyecol and yyeline give the position for an
64  * error message to flag, usually the start of an input token.
65  * Yylval is the semantic return from the scanner.
66  *
67  * In fact all of these variables are "per token".
68  * In the usual case, only the copies in the scanner token structure
69  * 'Y' are used, and the #defines below serve to make them look
70  * like variables.
71  *
72  * For the purposes of the error recovery, however, they are copied
73  * and restored quite freely.  For the error recovery also, the
74  * file name which the input line this token is on and the seek
75  * pointer of this line in its source file are saved as yyefile
76  * and yyseekp.  The global variable yylinpt is the seek pointer
77  * of the current input line.
78  */
79 int	yycol;
80 int	yyline;
81 int	yyseqid;
82 int	yysavc;
83 int	yylinpt;
84 
85 /* *** NOTE ***
86  * It would be much better to not have the Yyeline and Yyefile
87  * in the scanner structure and to have a mechanism for mapping
88  * seqid's to these globally.
89  */
90 struct yytok {
91 	int	Yychar;
92 	int	Yylval;
93 	int	Yyecol;
94 	int	Yyeline;
95 	int	Yyseekp;
96 	char	*Yyefile;
97 	int	Yyeseqid;
98 } Y, OY;
99 
100 #define	yychar	Y.Yychar
101 #define	yylval	Y.Yylval
102 #define	yyecol	Y.Yyecol
103 #define	yyeline	Y.Yyeline
104 #define	yyseekp	Y.Yyseekp
105 #define	yyefile	Y.Yyefile
106 #define	yyeseqid Y.Yyeseqid
107 
108 /* Semantic Stack so that y.tab.c will lint */
109 
110 union semstack
111 {
112     int		  i_entry;
113     struct nl	 *nl_entry;
114     struct tnode *tr_entry;
115     char	 *cptr;
116 } yyval;
117 
118 /*
119  * Yyval is the semantic value returned by a reduction.
120  * It is what "$$" is expanded to by yacc.
121  */
122 
123 int	*Ps;
124 
125 /*
126  * N is the length of a reduction.
127  * Used externally by "lineof" to get the left and
128  * right margins for a reduction.
129  */
130 int	N;
131 /*
132  * Definitions for looking up keywords.
133  * The keyword array is called yykey, and
134  * lastkey points at the end of it.
135  */
136 char	*lastkey;
137 
138 struct kwtab {
139 	char	*kw_str;
140 	int	kw_val;
141 } yykey[];
142 
143 /*
144  * ERROR RECOVERY EXTERNALS
145  */
146 
147 #define	CLIMIT	40	/* see yyrecover.c */
148 char	*tokname();
149 char	*charname();
150 
151 char	*classes[];
152 
153 /*
154  * Tokens which yacc doesn't define
155  */
156 #define	YEOF	0
157 #define	ERROR	256
158 
159 /*
160  * Limit on the number of syntax errors
161  */
162 #define	MAXSYNERR	100
163 
164 /*
165  * Big costs
166  */
167 #define	HUGE		50
168 #define	INFINITY	100
169 
170 /*
171  * Kinds of panics
172  */
173 #define	PDECL	0
174 #define	PSTAT	1
175 #define	PEXPR	2
176 #define	PPROG	3
177 
178 #define	yyresume()	yyResume = 1;
179 
180 char	yyResume;
181 
182 char	dquote;
183 
184 #ifndef PC
185 #ifndef OBJ
186 char	errout;
187 #endif OBJ
188 #endif PC
189 
190 /*
191  * Yyidwant and yyidhave are the namelist classes
192  * of identifiers associated with a identifier reduce
193  * error, set before the recovery is called.
194  * Since they may be set again during the forward move
195  * they must be saved by yyrecover, which uses them in printing
196  * error messages.
197  */
198 int	yyidhave, yyidwant;
199 
200 /*
201  * The variables yy*shifts are used to prevent looping and the printing
202  * of spurious messages in the parser.  Yyshifts gives the number of
203  * true input shifts since the last corrective action.  YyOshifts
204  * is the value of yyshifts before it was last cleared, and is used
205  * by yyPerror in yypanic.c to suppress messages.
206  *
207  * Yytshifts counts true input shifts.  It is used to prevent looping
208  * inserting unique symbols.  If yytshifts == yyTshifts (local to
209  * yyrecover.c) then there has been no shift over true input since
210  * the last unique symbol insertion.  We refuse, in this case,
211  * to insert more unique symbols so as to prevent looping.
212  *
213  * The recovery cannot loop because it guarantees the progress of the
214  * parse, i.e.:
215  *
216  *	1) Any insertion guarantees to shift over 2 symbols, a replacement
217  *	   over one symbol.
218  *
219  *	2) Unique symbol insertions are limited to one for each true
220  *	   symbol of input, or "safe" insertion of the keywords "end"
221  *	   and "until" at zero cost (safe since these are know to match
222  *	   stack that cannot have been generated - e.g. "begin" or "repeat")
223  *
224  *	3) We never panic more than once from a given state without
225  *	   shifting over input, i.e. we force the parse stack to shrink
226  *	   after each unsuccessful panic.
227  */
228 int	yyshifts, yyOshifts;
229 unsigned yytshifts;
230 
231 #ifdef PXP
232 
233 /*
234  * Identifier class definitions
235  */
236 #define	UNDEF	0
237 #define	CONST	1
238 #define	TYPE	2
239 #define	VAR	3
240 #define	ARRAY	4
241 #define	PTRFILE	5
242 #define	RECORD	6
243 #define	FIELD	7
244 #define	PROC	8
245 #define	FUNC	9
246 #define	FVAR	10
247 #define	REF	11
248 #define	PTR	12
249 #define	FILET	13
250 #define	SET	14
251 #define	RANGE	15
252 #define	LABEL	16
253 #define	WITHPTR 17
254 #define	SCAL	18
255 #define	STR	19
256 #define	PROG	20
257 #define	IMPROPER 21
258 
259 /*
260  * COMMENT FORMATTING DEFINITIONS
261  */
262 
263 /*
264  * Count of tokens on this input line
265  * Note that this can be off if input is not syntactically correct.
266  */
267 int	yytokcnt;
268 int	yywhcnt;
269 
270 /*
271  * Types of comments
272  */
273 #define	CLMARG	0
274 #define	CALIGN	1
275 #define	CTRAIL	2
276 #define	CRMARG	3
277 #define	CSRMARG	4
278 #define	CNL	5
279 #define	CNLBL	6
280 #define	CFORM	7
281 #define	CINCLUD	8
282 
283 /*
284  * Comment structure
285  * Cmhp is the head of the current list of comments
286  */
287 struct comment {
288 	struct	comment *cmnext;
289 	int	cmdelim;
290 	struct	commline *cml;
291 	int	cmjust;
292 	int	cmseqid;
293 } *cmhp;
294 
295 /*
296  * Structure for holding a comment line
297  */
298 struct commline {
299 	char	*cmtext;
300 	int	cmcol;	/* Only used for first line of comment currently */
301 	struct	commline *cml;
302 };
303 
304 struct W {
305 	int	Wseqid;
306 	int	Wcol;
307 } yyw[MAXDEPTH + 1], *yypw;
308 
309 #define	commform()	quickcomm(CFORM)
310 #define	commnl()	quickcomm(CNL)
311 #define	commnlbl()	quickcomm(CNLBL)
312 #endif
313