1/* Bison code properties structure and scanner.
2
3 Copyright (C) 2006-2007, 2009-2015, 2018-2019 Free Software
4 Foundation, Inc.
5
6 This file is part of Bison, the GNU Compiler Compiler.
7
8 This program is free software: you can redistribute it and/or modify
9 it under the terms of the GNU General Public License as published by
10 the Free Software Foundation, either version 3 of the License, or
11 (at your option) any later version.
12
13 This program is distributed in the hope that it will be useful,
14 but WITHOUT ANY WARRANTY; without even the implied warranty of
15 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 GNU General Public License for more details.
17
18 You should have received a copy of the GNU General Public License
19 along with this program. If not, see <http://www.gnu.org/licenses/>. */
20
21#ifndef SCAN_CODE_H_
22# define SCAN_CODE_H_
23
24# include "location.h"
25# include "named-ref.h"
26# include "uniqstr.h"
27
28struct symbol_list;
29
30/**
31 * Keeps track of the maximum number of semantic values to the left of a handle
32 * (those referenced by $0, $-1, etc.) that are required by the semantic
33 * actions of this grammar.
34 */
35extern int max_left_semantic_context;
36
37/**
38 * A code passage captured from the grammar file and possibly translated,
39 * and/or properties associated with such a code passage. Don't break
40 * encapsulation by modifying the fields directly. Use the provided interface
41 * functions.
42 */
43typedef struct code_props {
44 /** Set by the init functions. */
45 enum {
46 CODE_PROPS_NONE, CODE_PROPS_PLAIN,
47 CODE_PROPS_SYMBOL_ACTION, CODE_PROPS_RULE_ACTION
48 } kind;
49
50 /**
51 * \c NULL iff \c code_props::kind is \c CODE_PROPS_NONE.
52 * Memory is allocated in an obstack freed elsewhere.
53 */
54 char const *code;
55 /** Undefined iff \c code_props::code is \c NULL. */
56 location location;
57
58 /**
59 * \c false iff either:
60 * - \c code_props_translate_code has never previously been invoked for
61 * the \c code_props that would contain the code passage associated
62 * with \c self. (That \c code_props is not the same as this one if this
63 * one is for a RHS \c symbol_list node. Instead, it's the \c code_props
64 * for the LHS symbol of the same rule.)
65 * - \c code_props_translate_code has been invoked for that \c code_props,
66 * but the symbol value associated with this \c code_props was not
67 * referenced in the code passage.
68 */
69 bool is_value_used;
70
71 /**
72 * \c true iff this code is an action that is not to be deferred in
73 * a non-deterministic parser.
74 */
75 bool is_predicate;
76
77 /**
78 * Whether this is actually used (i.e., not completely masked by
79 * other code props). */
80 bool is_used;
81
82 /** \c NULL iff \c code_props::kind is not \c CODE_PROPS_RULE_ACTION. */
83 struct symbol_list *rule;
84
85 /** Named reference. */
86 named_ref *named_ref;
87
88 /** Type, for midrule actions. */
89 uniqstr type;
90} code_props;
91
92/**
93 * \pre
94 * - <tt>self != NULL</tt>.
95 * \post
96 * - \c self has been overwritten to contain no code.
97 */
98void code_props_none_init (code_props *self);
99
100/** Equivalent to \c code_props_none_init. */
101# define CODE_PROPS_NONE_INIT \
102 { \
103 /* .kind = */ CODE_PROPS_NONE, \
104 /* .code = */ NULL, \
105 /* .location = */ EMPTY_LOCATION_INIT, \
106 /* .is_value_used = */ false, \
107 /* .is_predicate = */ false, \
108 /* .is_used = */ false, \
109 /* .rule = */ NULL, \
110 /* .named_ref = */ NULL, \
111 /* .type = */ NULL, \
112 }
113
114/** Initialized by \c CODE_PROPS_NONE_INIT with no further modification. */
115extern code_props code_props_none;
116
117/**
118 * \pre
119 * - <tt>self != NULL</tt>.
120 * - <tt>code != NULL</tt>.
121 * - \c code is an untranslated code passage containing no Bison escapes.
122 * - \c code was extracted from the grammar file at \c code_loc.
123 * \post
124 * - \c self has been overwritten to represent the specified plain code
125 * passage.
126 * - \c self will become invalid if the caller frees \c code before invoking
127 * \c code_props_translate_code on \c self.
128 */
129void code_props_plain_init (code_props *self, char const *code,
130 location code_loc);
131
132/**
133 * \pre
134 * - <tt>self != NULL</tt>.
135 * - <tt>code != NULL</tt>.
136 * - \c code is an untranslated code passage. The only Bison escapes it
137 * might contain are $$ and \@$, referring to a single symbol.
138 * - \c code was extracted from the grammar file at \c code_loc.
139 * \post
140 * - \c self has been overwritten to represent the specified symbol action.
141 * - \c self will become invalid if the caller frees \c code before invoking
142 * \c code_props_translate_code on \c self.
143 */
144void code_props_symbol_action_init (code_props *self, char const *code,
145 location code_loc);
146
147/**
148 * \pre
149 * - <tt>self != NULL</tt>.
150 * - <tt>code != NULL</tt>.
151 * - <tt>rule != NULL</tt>.
152 * - \c code is the untranslated action of the rule for which \c rule is the
153 * LHS node. Thus, \c code possibly contains Bison escapes such as $$, $1,
154 * $2, etc referring to the values of the rule.
155 * - \c code was extracted from the grammar file at \c code_loc.
156 * \post
157 * - \c self has been overwritten to represent the specified rule action.
158 * - \c self does not claim responsibility for the memory of \c rule.
159 * - \c self will become invalid if:
160 * - The caller frees \c code before invoking \c code_props_translate_code
161 * on \c self.
162 * - The caller frees \c rule.
163 */
164void code_props_rule_action_init (code_props *self, char const *code,
165 location code_loc, struct symbol_list *rule,
166 named_ref *name, uniqstr type,
167 bool is_predicate);
168
169/**
170 * \pre
171 * - If there's a code passage contained in \c self and it contains Bison
172 * escapes, all grammar declarations have already been parsed as they may
173 * affect warnings and complaints issued here.
174 * \post
175 * - All M4-special symbols and Bison escapes have been translated in
176 * \c self->code.
177 * - <tt>self->code != self->code\@pre</tt> unless
178 * <tt>self->code\@pre = NULL</tt>.
179 */
180void code_props_translate_code (code_props *self);
181
182/**
183 * \pre
184 * - None.
185 * \post
186 * - The dynamic memory allocated by the previous invocation of
187 * \c code_props_translate_code (if any) was freed. The \c code_props
188 * instance for which \c code_props_translate_code was invoked is now
189 * invalid.
190 */
191void code_scanner_last_string_free (void);
192
193/**
194 * \pre
195 * - None.
196 * \post
197 * - All dynamic memory allocated during invocations of
198 * \c code_props_translate_code (if any) has been freed. All \c code_props
199 * instances may now be invalid.
200 */
201void code_scanner_free (void);
202
203#endif /* !SCAN_CODE_H_ */
204