src/scan-code.h

   1 /* Bison code properties structure and scanner.
   2
   3    Copyright (C) 2006-2007, 2009-2012 Free Software Foundation, Inc.
   4
   5    This file is part of Bison, the GNU Compiler Compiler.
   6
   7    This program is free software: you can redistribute it and/or modify
   8    it under the terms of the GNU General Public License as published by
   9    the Free Software Foundation, either version 3 of the License, or
  10    (at your option) any later version.
  11
  12    This program is distributed in the hope that it will be useful,
  13    but WITHOUT ANY WARRANTY; without even the implied warranty of
  14    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15    GNU General Public License for more details.
  16
  17    You should have received a copy of the GNU General Public License
  18    along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
  19
  20 #ifndef SCAN_CODE_H_
  21 # define SCAN_CODE_H_
  22
  23 # include "location.h"
  24 # include "named-ref.h"
  25
  26 struct symbol_list;
  27
  28 /**
  29  * Keeps track of the maximum number of semantic values to the left of a handle
  30  * (those referenced by $0, $-1, etc.) that are required by the semantic
  31  * actions of this grammar.
  32  */
  33 extern int max_left_semantic_context;
  34
  35 /**
  36  * A code passage captured from the grammar file and possibly translated,
  37  * and/or properties associated with such a code passage.  Don't break
  38  * encapsulation by modifying the fields directly.  Use the provided interface
  39  * functions.
  40  */
  41 typedef struct code_props {
  42   /** Set by the init functions.  */
  43   enum {
  44     CODE_PROPS_NONE, CODE_PROPS_PLAIN,
  45     CODE_PROPS_SYMBOL_ACTION, CODE_PROPS_RULE_ACTION
  46   } kind;
  47
  48   /** \c NULL iff \c code_props::kind is \c CODE_PROPS_NONE.  */
  49   char const *code;
  50   /** Undefined iff \c code_props::code is \c NULL.  */
  51   location location;
  52
  53   /**
  54    * \c false iff either:
  55    *   - \c code_props_translate_code has never previously been invoked for
  56    *     the \c code_props that would contain the code passage associated
  57    *     with \c self.  (That \c code_props is not the same as this one if this
  58    *     one is for a RHS \c symbol_list node.  Instead, it's the \c code_props
  59    *     for the LHS symbol of the same rule.)
  60    *   - \c code_props_translate_code has been invoked for that \c code_props,
  61    *     but the symbol value associated with this \c code_props was not
  62    *     referenced in the code passage.
  63    */
  64   bool is_value_used;
  65
  66   /**
  67    * \c true iff this code is an action that is not to be deferred in
  68    * a non-deterministic parser.
  69    */
  70   bool is_predicate;
  71
  72   /**
  73    * Whether this is actually used (i.e., not completely masked by
  74    * other code props).  */
  75   bool is_used;
  76
  77   /** \c NULL iff \c code_props::kind is not \c CODE_PROPS_RULE_ACTION.  */
  78   struct symbol_list *rule;
  79
  80   /* Named reference. */
  81   named_ref *named_ref;
  82 } code_props;
  83
  84 /**
  85  * \pre
  86  *   - <tt>self != NULL</tt>.
  87  * \post
  88  *   - \c self has been overwritten to contain no code.
  89  */
  90 void code_props_none_init (code_props *self);
  91
  92 /** Equivalent to \c code_props_none_init.  */
  93 #define CODE_PROPS_NONE_INIT                    \
  94   {                                             \
  95     /* .kind = */ CODE_PROPS_NONE,              \
  96     /* .code = */ NULL,                         \
  97     /* .location = */ EMPTY_LOCATION_INIT,      \
  98     /* .is_value_used = */ false,               \
  99     /* .is_predicate = */ false,                \
 100     /* .is_used = */ false,                     \
 101     /* .rule = */ NULL,                         \
 102     /* .named_ref = */ NULL                     \
 103   }
 104
 105 /** Initialized by \c CODE_PROPS_NONE_INIT with no further modification.  */
 106 extern code_props const code_props_none;
 107
 108 /**
 109  * \pre
 110  *   - <tt>self != NULL</tt>.
 111  *   - <tt>code != NULL</tt>.
 112  *   - \c code is an untranslated code passage containing no Bison escapes.
 113  *   - \c code was extracted from the grammar file at \c code_loc.
 114  * \post
 115  *   - \c self has been overwritten to represent the specified plain code
 116  *     passage.
 117  *   - \c self will become invalid if the caller frees \c code before invoking
 118  *     \c code_props_translate_code on \c self.
 119  */
 120 void code_props_plain_init (code_props *self, char const *code,
 121                             location code_loc);
 122
 123 /**
 124  * \pre
 125  *   - <tt>self != NULL</tt>.
 126  *   - <tt>code != NULL</tt>.
 127  *   - \c code is an untranslated code passage.  The only Bison escapes it
 128  *     might contain are $$ and \@$, referring to a single symbol.
 129  *   - \c code was extracted from the grammar file at \c code_loc.
 130  * \post
 131  *   - \c self has been overwritten to represent the specified symbol action.
 132  *   - \c self will become invalid if the caller frees \c code before invoking
 133  *     \c code_props_translate_code on \c self.
 134  */
 135 void code_props_symbol_action_init (code_props *self, char const *code,
 136                                     location code_loc);
 137
 138 /**
 139  * \pre
 140  *   - <tt>self != NULL</tt>.
 141  *   - <tt>code != NULL</tt>.
 142  *   - <tt>rule != NULL</tt>.
 143  *   - \c code is the untranslated action of the rule for which \c rule is the
 144  *     LHS node.  Thus, \c code possibly contains Bison escapes such as $$, $1,
 145  *     $2, etc referring to the values of the rule.
 146  *   - \c code was extracted from the grammar file at \c code_loc.
 147  * \post
 148  *   - \c self has been overwritten to represent the specified rule action.
 149  *   - \c self does not claim responsibility for the memory of \c rule.
 150  *   - \c self will become invalid if:
 151  *     - The caller frees \c code before invoking \c code_props_translate_code
 152  *       on \c self.
 153  *     - The caller frees \c rule.
 154  */
 155 void code_props_rule_action_init (code_props *self, char const *code,
 156                                   location code_loc, struct symbol_list *rule,
 157                                   named_ref *name, bool is_predicate);
 158
 159 /**
 160  * \pre
 161  *   - If there's a code passage contained in \c self and it contains Bison
 162  *     escapes, all grammar declarations have already been parsed as they may
 163  *     affect warnings and complaints issued here.
 164  * \post
 165  *   - All M4-special symbols and Bison escapes have been translated in
 166  *     \c self->code.
 167  *   - <tt>self->code != self->code\@pre</tt> unless
 168  *     <tt>self->code\@pre = NULL</tt>.
 169  */
 170 void code_props_translate_code (code_props *self);
 171
 172 /**
 173  * \pre
 174  *   - None.
 175  * \post
 176  *   - The dynamic memory allocated by the previous invocation of
 177  *     \c code_props_translate_code (if any) was freed.  The \c code_props
 178  *     instance for which \c code_props_translate_code was invoked is now
 179  *     invalid.
 180  */
 181 void code_scanner_last_string_free (void);
 182
 183 /**
 184  * \pre
 185  *   - None.
 186  * \post
 187  *   - All dynamic memory allocated during invocations of
 188  *     \c code_props_translate_code (if any) has been freed.  All \c code_props
 189  *     instances may now be invalid.
 190  */
 191 void code_scanner_free (void);
 192
 193 #endif /* !SCAN_CODE_H_ */