src/scan-code.h

   1 /* Bison code properties structure and scanner.
   2
   3    Copyright (C) 2006, 2007 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
  25 struct symbol_list;
  26
  27 /**
  28  * Keeps track of the maximum number of semantic values to the left of a handle
  29  * (those referenced by $0, $-1, etc.) that are required by the semantic
  30  * actions of this grammar.
  31  */
  32 extern int max_left_semantic_context;
  33
  34 /**
  35  * A code passage captured from the grammar file and possibly translated,
  36  * and/or properties associated with such a code passage.  Don't break
  37  * encapsulation by modifying the fields directly.  Use the provided interface
  38  * functions.
  39  */
  40 typedef struct code_props {
  41   /** Set by the init functions.  */
  42   enum {
  43     CODE_PROPS_NONE, CODE_PROPS_PLAIN,
  44     CODE_PROPS_SYMBOL_ACTION, CODE_PROPS_RULE_ACTION
  45   } kind;
  46
  47   /** \c NULL iff \c code_props::kind is \c CODE_PROPS_NONE.  */
  48   char const *code;
  49   /** Undefined iff \c code_props::code is \c NULL.  */
  50   location location;
  51
  52   /**
  53    * \c false iff either:
  54    *   - \c code_props_translate_code has never previously been invoked for
  55    *     the \c code_props that would contain the code passage associated
  56    *     with \c self.  (That \c code_props is not the same as this one if this
  57    *     one is for a RHS \c symbol_list node.  Instead, it's the \c code_props
  58    *     for the LHS symbol of the same rule.)
  59    *   - \c code_props_translate_code has been invoked for that \c code_props,
  60    *     but the symbol value associated with this \c code_props was not
  61    *     referenced in the code passage.
  62    */
  63   bool is_value_used;
  64
  65   /** \c NULL iff \c code_props::kind is not \c CODE_PROPS_RULE_ACTION.  */
  66   struct symbol_list *rule;
  67 } code_props;
  68
  69 /**
  70  * \pre
  71  *   - <tt>self != NULL</tt>.
  72  * \post
  73  *   - \c self has been overwritten to contain no code.
  74  */
  75 void code_props_none_init (code_props *self);
  76
  77 /** Equivalent to \c code_props_none_init.  */
  78 #define CODE_PROPS_NONE_INIT \
  79   {CODE_PROPS_NONE, NULL, EMPTY_LOCATION_INIT, false, NULL}
  80
  81 /** Initialized by \c CODE_PROPS_NONE_INIT with no further modification.  */
  82 extern code_props const code_props_none;
  83
  84 /**
  85  * \pre
  86  *   - <tt>self != NULL</tt>.
  87  *   - <tt>code != NULL</tt>.
  88  *   - \c code is an untranslated code passage containing no Bison escapes.
  89  *   - \c code was extracted from the grammar file at \c code_loc.
  90  * \post
  91  *   - \c self has been overwritten to represent the specified plain code
  92  *     passage.
  93  *   - \c self will become invalid if the caller frees \c code before invoking
  94  *     \c code_props_translate_code on \c self.
  95  */
  96 void code_props_plain_init (code_props *self, char const *code,
  97                             location code_loc);
  98
  99 /**
 100  * \pre
 101  *   - <tt>self != NULL</tt>.
 102  *   - <tt>code != NULL</tt>.
 103  *   - \c code is an untranslated code passage.  The only Bison escapes it
 104  *     might contain are $$ and \@$, referring to a single symbol.
 105  *   - \c code was extracted from the grammar file at \c code_loc.
 106  * \post
 107  *   - \c self has been overwritten to represent the specified symbol action.
 108  *   - \c self will become invalid if the caller frees \c code before invoking
 109  *     \c code_props_translate_code on \c self.
 110  */
 111 void code_props_symbol_action_init (code_props *self, char const *code,
 112                                     location code_loc);
 113
 114 /**
 115  * \pre
 116  *   - <tt>self != NULL</tt>.
 117  *   - <tt>code != NULL</tt>.
 118  *   - <tt>rule != NULL</tt>.
 119  *   - \c code is the untranslated action of the rule for which \c rule is the
 120  *     LHS node.  Thus, \c code possibly contains Bison escapes such as $$, $1,
 121  *     $2, etc referring to the values of the rule.
 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 rule action.
 125  *   - \c self does not claim responsibility for the memory of \c rule.
 126  *   - \c self will become invalid if:
 127  *     - The caller frees \c code before invoking \c code_props_translate_code
 128  *       on \c self.
 129  *     - The caller frees \c rule.
 130  */
 131 void code_props_rule_action_init (code_props *self, char const *code,
 132                                   location code_loc, struct symbol_list *rule);
 133
 134 /**
 135  * \pre
 136  *   - If there's a code passage contained in \c self and it contains Bison
 137  *     escapes, all grammar declarations have already been parsed as they may
 138  *     affect warnings and complaints issued here.
 139  * \post
 140  *   - All M4-special symbols and Bison escapes have been translated in
 141  *     \c self->code.
 142  *   - <tt>self->code != self->code\@pre</tt> unless
 143  *     <tt>self->code\@pre = NULL</tt>.
 144  */
 145 void code_props_translate_code (code_props *self);
 146
 147 /**
 148  * \pre
 149  *   - None.
 150  * \post
 151  *   - The dynamic memory allocated by the previous invocation of
 152  *     \c code_props_translate_code (if any) was freed.  The \c code_props
 153  *     instance for which \c code_props_translate_code was invoked is now
 154  *     invalid.
 155  */
 156 void code_scanner_last_string_free (void);
 157
 158 /**
 159  * \pre
 160  *   - None.
 161  * \post
 162  *   - All dynamic memory allocated during invocations of
 163  *     \c code_props_translate_code (if any) has been freed.  All \c code_props
 164  *     instances may now be invalid.
 165  */
 166 void code_scanner_free (void);
 167
 168 #endif /* !SCAN_CODE_H_ */