src/scan-code.h

   1 /* Bison code properties structure and scanner.
   2
   3    Copyright (C) 2006, 2007, 2009, 2010 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   /** \c NULL iff \c code_props::kind is not \c CODE_PROPS_RULE_ACTION.  */
  74   struct symbol_list *rule;
  75
  76   /* Named reference. */
  77   named_ref *named_ref;
  78 } code_props;
  79
  80 /**
  81  * \pre
  82  *   - <tt>self != NULL</tt>.
  83  * \post
  84  *   - \c self has been overwritten to contain no code.
  85  */
  86 void code_props_none_init (code_props *self);
  87
  88 /** Equivalent to \c code_props_none_init.  */
  89 #define CODE_PROPS_NONE_INIT \
  90   {CODE_PROPS_NONE, NULL, EMPTY_LOCATION_INIT, false, false, NULL, NULL}
  91
  92 /** Initialized by \c CODE_PROPS_NONE_INIT with no further modification.  */
  93 extern code_props const code_props_none;
  94
  95 /**
  96  * \pre
  97  *   - <tt>self != NULL</tt>.
  98  *   - <tt>code != NULL</tt>.
  99  *   - \c code is an untranslated code passage containing no Bison escapes.
 100  *   - \c code was extracted from the grammar file at \c code_loc.
 101  * \post
 102  *   - \c self has been overwritten to represent the specified plain code
 103  *     passage.
 104  *   - \c self will become invalid if the caller frees \c code before invoking
 105  *     \c code_props_translate_code on \c self.
 106  */
 107 void code_props_plain_init (code_props *self, char const *code,
 108                             location code_loc);
 109
 110 /**
 111  * \pre
 112  *   - <tt>self != NULL</tt>.
 113  *   - <tt>code != NULL</tt>.
 114  *   - \c code is an untranslated code passage.  The only Bison escapes it
 115  *     might contain are $$ and \@$, referring to a single symbol.
 116  *   - \c code was extracted from the grammar file at \c code_loc.
 117  * \post
 118  *   - \c self has been overwritten to represent the specified symbol action.
 119  *   - \c self will become invalid if the caller frees \c code before invoking
 120  *     \c code_props_translate_code on \c self.
 121  */
 122 void code_props_symbol_action_init (code_props *self, char const *code,
 123                                     location code_loc);
 124
 125 /**
 126  * \pre
 127  *   - <tt>self != NULL</tt>.
 128  *   - <tt>code != NULL</tt>.
 129  *   - <tt>rule != NULL</tt>.
 130  *   - \c code is the untranslated action of the rule for which \c rule is the
 131  *     LHS node.  Thus, \c code possibly contains Bison escapes such as $$, $1,
 132  *     $2, etc referring to the values of the rule.
 133  *   - \c code was extracted from the grammar file at \c code_loc.
 134  * \post
 135  *   - \c self has been overwritten to represent the specified rule action.
 136  *   - \c self does not claim responsibility for the memory of \c rule.
 137  *   - \c self will become invalid if:
 138  *     - The caller frees \c code before invoking \c code_props_translate_code
 139  *       on \c self.
 140  *     - The caller frees \c rule.
 141  */
 142 void code_props_rule_action_init (code_props *self, char const *code,
 143                                   location code_loc, struct symbol_list *rule,
 144                                   named_ref *name, bool is_predicate);
 145
 146 /**
 147  * \pre
 148  *   - If there's a code passage contained in \c self and it contains Bison
 149  *     escapes, all grammar declarations have already been parsed as they may
 150  *     affect warnings and complaints issued here.
 151  * \post
 152  *   - All M4-special symbols and Bison escapes have been translated in
 153  *     \c self->code.
 154  *   - <tt>self->code != self->code\@pre</tt> unless
 155  *     <tt>self->code\@pre = NULL</tt>.
 156  */
 157 void code_props_translate_code (code_props *self);
 158
 159 /**
 160  * \pre
 161  *   - None.
 162  * \post
 163  *   - The dynamic memory allocated by the previous invocation of
 164  *     \c code_props_translate_code (if any) was freed.  The \c code_props
 165  *     instance for which \c code_props_translate_code was invoked is now
 166  *     invalid.
 167  */
 168 void code_scanner_last_string_free (void);
 169
 170 /**
 171  * \pre
 172  *   - None.
 173  * \post
 174  *   - All dynamic memory allocated during invocations of
 175  *     \c code_props_translate_code (if any) has been freed.  All \c code_props
 176  *     instances may now be invalid.
 177  */
 178 void code_scanner_free (void);
 179
 180 #endif /* !SCAN_CODE_H_ */