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   /**
  49    * \c NULL iff \c code_props::kind is \c CODE_PROPS_NONE.
  50    * Memory is allocated in an obstack freed elsewhere.
  51    */
  52   char const *code;
  53   /** Undefined iff \c code_props::code is \c NULL.  */
  54   location location;
  55
  56   /**
  57    * \c false iff either:
  58    *   - \c code_props_translate_code has never previously been invoked for
  59    *     the \c code_props that would contain the code passage associated
  60    *     with \c self.  (That \c code_props is not the same as this one if this
  61    *     one is for a RHS \c symbol_list node.  Instead, it's the \c code_props
  62    *     for the LHS symbol of the same rule.)
  63    *   - \c code_props_translate_code has been invoked for that \c code_props,
  64    *     but the symbol value associated with this \c code_props was not
  65    *     referenced in the code passage.
  66    */
  67   bool is_value_used;
  68
  69   /** \c NULL iff \c code_props::kind is not \c CODE_PROPS_RULE_ACTION.  */
  70   struct symbol_list *rule;
  71
  72   /* Named reference. */
  73   named_ref *named_ref;
  74 } code_props;
  75
  76 /**
  77  * \pre
  78  *   - <tt>self != NULL</tt>.
  79  * \post
  80  *   - \c self has been overwritten to contain no code.
  81  */
  82 void code_props_none_init (code_props *self);
  83
  84 /** Equivalent to \c code_props_none_init.  */
  85 #define CODE_PROPS_NONE_INIT \
  86   {CODE_PROPS_NONE, NULL, EMPTY_LOCATION_INIT, false, NULL, NULL}
  87
  88 /** Initialized by \c CODE_PROPS_NONE_INIT with no further modification.  */
  89 extern code_props const code_props_none;
  90
  91 /**
  92  * \pre
  93  *   - <tt>self != NULL</tt>.
  94  *   - <tt>code != NULL</tt>.
  95  *   - \c code is an untranslated code passage containing no Bison escapes.
  96  *   - \c code was extracted from the grammar file at \c code_loc.
  97  * \post
  98  *   - \c self has been overwritten to represent the specified plain code
  99  *     passage.
 100  *   - \c self will become invalid if the caller frees \c code before invoking
 101  *     \c code_props_translate_code on \c self.
 102  */
 103 void code_props_plain_init (code_props *self, char const *code,
 104                             location code_loc);
 105
 106 /**
 107  * \pre
 108  *   - <tt>self != NULL</tt>.
 109  *   - <tt>code != NULL</tt>.
 110  *   - \c code is an untranslated code passage.  The only Bison escapes it
 111  *     might contain are $$ and \@$, referring to a single symbol.
 112  *   - \c code was extracted from the grammar file at \c code_loc.
 113  * \post
 114  *   - \c self has been overwritten to represent the specified symbol action.
 115  *   - \c self will become invalid if the caller frees \c code before invoking
 116  *     \c code_props_translate_code on \c self.
 117  */
 118 void code_props_symbol_action_init (code_props *self, char const *code,
 119                                     location code_loc);
 120
 121 /**
 122  * \pre
 123  *   - <tt>self != NULL</tt>.
 124  *   - <tt>code != NULL</tt>.
 125  *   - <tt>rule != NULL</tt>.
 126  *   - \c code is the untranslated action of the rule for which \c rule is the
 127  *     LHS node.  Thus, \c code possibly contains Bison escapes such as $$, $1,
 128  *     $2, etc referring to the values of the rule.
 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 rule action.
 132  *   - \c self does not claim responsibility for the memory of \c rule.
 133  *   - \c self will become invalid if:
 134  *     - The caller frees \c code before invoking \c code_props_translate_code
 135  *       on \c self.
 136  *     - The caller frees \c rule.
 137  */
 138 void code_props_rule_action_init (code_props *self, char const *code,
 139                                   location code_loc, struct symbol_list *rule,
 140                                   named_ref *name);
 141
 142 /**
 143  * \pre
 144  *   - If there's a code passage contained in \c self and it contains Bison
 145  *     escapes, all grammar declarations have already been parsed as they may
 146  *     affect warnings and complaints issued here.
 147  * \post
 148  *   - All M4-special symbols and Bison escapes have been translated in
 149  *     \c self->code.
 150  *   - <tt>self->code != self->code\@pre</tt> unless
 151  *     <tt>self->code\@pre = NULL</tt>.
 152  */
 153 void code_props_translate_code (code_props *self);
 154
 155 /**
 156  * \pre
 157  *   - None.
 158  * \post
 159  *   - The dynamic memory allocated by the previous invocation of
 160  *     \c code_props_translate_code (if any) was freed.  The \c code_props
 161  *     instance for which \c code_props_translate_code was invoked is now
 162  *     invalid.
 163  */
 164 void code_scanner_last_string_free (void);
 165
 166 /**
 167  * \pre
 168  *   - None.
 169  * \post
 170  *   - All dynamic memory allocated during invocations of
 171  *     \c code_props_translate_code (if any) has been freed.  All \c code_props
 172  *     instances may now be invalid.
 173  */
 174 void code_scanner_free (void);
 175
 176 #endif /* !SCAN_CODE_H_ */