parser.h revision 1.23 
1/*	$NetBSD: parser.h,v 1.23 2017/06/30 23:02:56 kre Exp $	*/
2
3/*-
4 * Copyright (c) 1991, 1993
5 *	The Regents of the University of California.  All rights reserved.
6 *
7 * This code is derived from software contributed to Berkeley by
8 * Kenneth Almquist.
9 *
10 * Redistribution and use in source and binary forms, with or without
11 * modification, are permitted provided that the following conditions
12 * are met:
13 * 1. Redistributions of source code must retain the above copyright
14 *    notice, this list of conditions and the following disclaimer.
15 * 2. Redistributions in binary form must reproduce the above copyright
16 *    notice, this list of conditions and the following disclaimer in the
17 *    documentation and/or other materials provided with the distribution.
18 * 3. Neither the name of the University nor the names of its contributors
19 *    may be used to endorse or promote products derived from this software
20 *    without specific prior written permission.
21 *
22 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
23 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
24 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
25 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
26 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
27 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
28 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
29 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
30 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
31 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
32 * SUCH DAMAGE.
33 *
34 *	@(#)parser.h	8.3 (Berkeley) 5/4/95
35 */
36
37/* control characters in argument strings */
38#define CTL_FIRST '\201'	/* first 'special' character */
39#define CTLESC '\201'		/* escape next character */
40#define CTLVAR '\202'		/* variable defn */
41#define CTLENDVAR '\203'
42#define CTLBACKQ '\204'
43#define CTLQUOTE 01		/* ored with CTLBACKQ code if in quotes */
44/*	CTLBACKQ | CTLQUOTE == '\205' */
45#define	CTLARI	'\206'		/* arithmetic expression */
46#define	CTLENDARI '\207'
47#define	CTLQUOTEMARK '\210'
48#define	CTLQUOTEEND '\211'	/* only inside ${...} */
49#define CTLNONL '\212'		/* The \n in a deleted \ \n sequence */
50			/* pure concidence that (CTLNONL & 0x7f) == '\n' */
51#define	CTL_LAST '\212'		/* last 'special' character */
52
53/* variable substitution byte (follows CTLVAR) */
54#define VSTYPE		0x0f	/* type of variable substitution */
55#define VSNUL		0x10	/* colon--treat the empty string as unset */
56#define VSLINENO	0x20	/* expansion of $LINENO, the line number
57				   follows immediately */
58#define VSPATQ		0x40	/* ensure correct pattern quoting in ${x#pat} */
59#define VSQUOTE	 	0x80	/* inside double quotes--suppress splitting */
60
61/* values of VSTYPE field */
62#define VSNORMAL	0x1		/* normal variable:  $var or ${var} */
63#define VSMINUS		0x2		/* ${var-text} */
64#define VSPLUS		0x3		/* ${var+text} */
65#define VSQUESTION	0x4		/* ${var?message} */
66#define VSASSIGN	0x5		/* ${var=text} */
67#define VSTRIMLEFT	0x6		/* ${var#pattern} */
68#define VSTRIMLEFTMAX	0x7		/* ${var##pattern} */
69#define VSTRIMRIGHT	0x8		/* ${var%pattern} */
70#define VSTRIMRIGHTMAX 	0x9		/* ${var%%pattern} */
71#define VSLENGTH	0xa		/* ${#var} */
72
73union node *parsecmd(int);
74void fixredir(union node *, const char *, int);
75int goodname(char *);
76const char *getprompt(void *);
77const char *expandstr(char *, int);
78
79struct HereDoc;
80union node;
81struct nodelist;
82
83struct parse_state {
84	int ps_noalias;			/* when set, don't handle aliases */
85	struct HereDoc *ps_heredoclist;	/* list of here documents to read */
86	int ps_parsebackquote;		/* nonzero inside backquotes */
87	int ps_doprompt;		/* if set, prompt the user */
88	int ps_needprompt;		/* true if interactive at line start */
89	int ps_lasttoken;		/* last token read */
90	int ps_tokpushback;		/* last token pushed back */
91	char *ps_wordtext;	/* text of last word returned by readtoken */
92	int ps_checkkwd;	/* 1 == check for kwds, 2 += eat newlines */
93	struct nodelist *ps_backquotelist; /* list of cmdsubs to process */
94	union node *ps_redirnode;	/* node for current redirect */
95	struct HereDoc *ps_heredoc;	/* current heredoc << beign parsed */
96	int ps_quoteflag;		/* set if (part) of token was quoted */
97	int ps_startlinno;		/* line # where last token started */
98	int ps_funclinno;		/* line # of the current function */
99	int ps_elided_nl;		/* count of \ \n pairs we have seen */
100};
101
102/*
103 * The parser references the elements of struct parse_state quite
104 * frequently - they used to be simple globals, so one memory ref
105 * per access, adding an indirect through global ptr would not be
106 * nice.   The following gross hack allows most of that cost to be
107 * avoided, by allowing the compiler to understand that the global
108 * pointer is in fact constant in any function, and so its value can
109 * be cached, rather than needing to be fetched every time in case
110 * some other called function has changed it.
111 *
112 * The rule to make this work is that any function that wants
113 * to alter the global must restore it before it returns (and thus
114 * must have an error trap handler).  That means that the struct
115 * used for the new parser state can be a local in that function's
116 * stack frame, it never needs to be malloc'd.
117 */
118
119union parse_state_p {
120	struct parse_state *const	c_current_parser;
121	struct parse_state *		v_current_parser;
122};
123
124extern union parse_state_p psp;
125
126#define	current_parser (psp.c_current_parser)
127
128/*
129 * Perhaps one day emulate "static" by moving most of these definitions into
130 * parser.c ...  (only checkkwd & tokpushback are used outside parser.c,
131 * and only in init.c as a RESET activity)
132 */
133#define	tokpushback	(current_parser->ps_tokpushback)
134#define	checkkwd	(current_parser->ps_checkkwd)
135
136#define	noalias		(current_parser->ps_noalias)
137#define	heredoclist	(current_parser->ps_heredoclist)
138#define	parsebackquote	(current_parser->ps_parsebackquote)
139#define	doprompt	(current_parser->ps_doprompt)
140#define	needprompt	(current_parser->ps_needprompt)
141#define	lasttoken	(current_parser->ps_lasttoken)
142#define	wordtext	(current_parser->ps_wordtext)
143#define	backquotelist	(current_parser->ps_backquotelist)
144#define	redirnode	(current_parser->ps_redirnode)
145#define	heredoc		(current_parser->ps_heredoc)
146#define	quoteflag	(current_parser->ps_quoteflag)
147#define	startlinno	(current_parser->ps_startlinno)
148#define	funclinno	(current_parser->ps_funclinno)
149#define	elided_nl	(current_parser->ps_elided_nl)
150
151/*
152 * NEOF is returned by parsecmd when it encounters an end of file.  It
153 * must be distinct from NULL, so we use the address of a variable that
154 * happens to be handy.
155 */
156#define NEOF ((union node *)&psp)
157
158#ifdef DEBUG
159extern int parsing;
160#endif
161