example2.cpp

学习lemon语法分析的windows程序

/* Driver template for the LEMON parser generator.
** The author disclaims copyright to this source code.
*/
/* First off, code is include which follows the "include" declaration
** in the input file. */
#include <stdio.h>
#line 55 "example2.y"
   
#include <iostream>  
#include "ex2def.h"
#include "example2.h"

#line 14 "example2.c"
/* Next is all token values, in a form suitable for use by makeheaders.
** This section will be null unless lemon is run with the -m switch.
*/
/* 
** These constants (all generated automatically by the parser generator)
** specify the various kinds of tokens (terminals) that the parser
** understands. 
**
** Each symbol here is a terminal symbol in the grammar.
*/
/* Make sure the INTERFACE macro is defined.
*/
#ifndef INTERFACE
# define INTERFACE 1
#endif
/* The next thing included is series of defines which control
** various aspects of the generated parser.
**    YYCODETYPE         is the data type used for storing terminal
**                       and nonterminal numbers.  "unsigned char" is
**                       used if there are fewer than 250 terminals
**                       and nonterminals.  "int" is used otherwise.
**    YYNOCODE           is a number of type YYCODETYPE which corresponds
**                       to no legal terminal or nonterminal number.  This
**                       number is used to fill in empty slots of the hash 
**                       table.
**    YYFALLBACK         If defined, this indicates that one or more tokens
**                       have fall-back values which should be used if the
**                       original value of the token will not parse.
**    YYACTIONTYPE       is the data type used for storing terminal
**                       and nonterminal numbers.  "unsigned char" is
**                       used if there are fewer than 250 rules and
**                       states combined.  "int" is used otherwise.
**    ParseTOKENTYPE     is the data type used for minor tokens given 
**                       directly to the parser from the tokenizer.
**    YYMINORTYPE        is the data type used for all minor tokens.
**                       This is typically a union of many types, one of
**                       which is ParseTOKENTYPE.  The entry in the union
**                       for base tokens is called "yy0".
**    YYSTACKDEPTH       is the maximum depth of the parser's stack.
**    ParseARG_SDECL     A static variable declaration for the %extra_argument
**    ParseARG_PDECL     A parameter declaration for the %extra_argument
**    ParseARG_STORE     Code to store %extra_argument into yypParser
**    ParseARG_FETCH     Code to extract %extra_argument from yypParser
**    YYNSTATE           the combined number of states.
**    YYNRULE            the number of rules in the grammar
**    YYERRORSYMBOL      is the code number of the error symbol.  If not
**                       defined, then do no error processing.
*/
#define YYCODETYPE unsigned char
#define YYNOCODE 10
#define YYACTIONTYPE unsigned char
#define ParseTOKENTYPE Token
typedef union {
  ParseTOKENTYPE yy0;
  Token yy18;
  int yy19;
} YYMINORTYPE;
#define YYSTACKDEPTH 100
#define ParseARG_SDECL
#define ParseARG_PDECL
#define ParseARG_FETCH
#define ParseARG_STORE
#define YYNSTATE 11
#define YYNRULE 6
#define YYERRORSYMBOL 6
#define YYERRSYMDT yy19
#define YY_NO_ACTION      (YYNSTATE+YYNRULE+2)
#define YY_ACCEPT_ACTION  (YYNSTATE+YYNRULE+1)
#define YY_ERROR_ACTION   (YYNSTATE+YYNRULE)

/* Next are that tables used to determine what action to take based on the
** current state and lookahead token.  These tables are used to implement
** functions that take a state number and lookahead value and return an
** action integer.  
**
** Suppose the action integer is N.  Then the action is determined as
** follows
**
**   0 <= N < YYNSTATE                  Shift N.  That is, push the lookahead
**                                      token onto the stack and goto state N.
**
**   YYNSTATE <= N < YYNSTATE+YYNRULE   Reduce by rule N-YYNSTATE.
**
**   N == YYNSTATE+YYNRULE              A syntax error has occurred.
**
**   N == YYNSTATE+YYNRULE+1            The parser accepts its input.
**
**   N == YYNSTATE+YYNRULE+2            No such action.  Denotes unused
**                                      slots in the yy_action[] table.
**
** The action table is constructed as a single large table named yy_action[].
** Given state S and lookahead X, the action is computed as
**
**      yy_action[ yy_shift_ofst[S] + X ]
**
** If the index value yy_shift_ofst[S]+X is out of range or if the value
** yy_lookahead[yy_shift_ofst[S]+X] is not equal to X or if yy_shift_ofst[S]
** is equal to YY_SHIFT_USE_DFLT, it means that the action is not in the table
** and that yy_default[S] should be used instead.  
**
** The formula above is for computing the action when the lookahead is
** a terminal symbol.  If the lookahead is a non-terminal (as occurs after
** a reduce action) then the yy_reduce_ofst[] array is used in place of
** the yy_shift_ofst[] array and YY_REDUCE_USE_DFLT is used in place of
** YY_SHIFT_USE_DFLT.
**
** The following are the tables generated in this section:
**
**  yy_action[]        A single table containing all actions.
**  yy_lookahead[]     A table containing the lookahead for each entry in
**                     yy_action.  Used to detect hash collisions.
**  yy_shift_ofst[]    For each state, the offset into yy_action for
**                     shifting terminals.
**  yy_reduce_ofst[]   For each state, the offset into yy_action for
**                     shifting non-terminals after a reduce.
**  yy_default[]       Default action for each state.
*/
static YYACTIONTYPE yy_action[] = {
 /*     0 */    11,    3,    4,    2,    8,    6,    1,   18,    8,    6,
 /*    10 */    10,   17,    9,    5,    7,
};
static YYCODETYPE yy_lookahead[] = {
 /*     0 */     0,    7,    2,    3,    4,    5,    7,    8,    4,    5,
 /*    10 */     1,    9,    7,    7,    7,
};
#define YY_SHIFT_USE_DFLT (-1)
static signed char yy_shift_ofst[] = {
 /*     0 */     9,    0,    9,    4,    9,    4,    9,   -1,    9,   -1,
 /*    10 */    -1,
};
#define YY_REDUCE_USE_DFLT (-7)
static signed char yy_reduce_ofst[] = {
 /*     0 */    -1,   -7,   -6,   -7,    6,   -7,    7,   -7,    5,   -7,
 /*    10 */    -7,
};
static YYACTIONTYPE yy_default[] = {
 /*     0 */    17,   17,   17,   12,   17,   13,   17,   14,   17,   15,
 /*    10 */    16,
};
#define YY_SZ_ACTTAB (sizeof(yy_action)/sizeof(yy_action[0]))

/* The next table maps tokens into fallback tokens.  If a construct
** like the following:
** 
**      %fallback ID X Y Z.
**
** appears in the grammer, then ID becomes a fallback token for X, Y,
** and Z.  Whenever one of the tokens X, Y, or Z is input to the parser
** but it does not parse, the type of the token is changed to ID and
** the parse is retried before an error is thrown.
*/
#ifdef YYFALLBACK
static const YYCODETYPE yyFallback[] = {
};
#endif /* YYFALLBACK */

/* The following structure represents a single element of the
** parser's stack.  Information stored includes:
**
**   +  The state number for the parser at this level of the stack.
**
**   +  The value of the token stored at this level of the stack.
**      (In other words, the "major" token.)
**
**   +  The semantic value stored at this level of the stack.  This is
**      the information used by the action routines in the grammar.
**      It is sometimes called the "minor" token.
*/
struct yyStackEntry {
  int stateno;       /* The state-number */
  int major;         /* The major token value.  This is the code
                     ** number for the token at this stack level */
  YYMINORTYPE minor; /* The user-supplied minor token value.  This
                     ** is the value of the token  */
};
typedef struct yyStackEntry yyStackEntry;

/* The state of the parser is completely contained in an instance of
** the following structure */
struct yyParser {
  int yyidx;                    /* Index of top element in stack */
  int yyerrcnt;                 /* Shifts left before out of the error */
  ParseARG_SDECL                /* A place to hold %extra_argument */
  yyStackEntry yystack[YYSTACKDEPTH];  /* The parser's stack */
};
typedef struct yyParser yyParser;

#ifndef NDEBUG
#include <stdio.h>
static FILE *yyTraceFILE = 0;
static char *yyTracePrompt = 0;
#endif /* NDEBUG */

#ifndef NDEBUG
/* 
** Turn parser tracing on by giving a stream to which to write the trace
** and a prompt to preface each trace message.  Tracing is turned off
** by making either argument NULL 
**
** Inputs:
** <ul>
** <li> A FILE* to which trace output should be written.
**      If NULL, then tracing is turned off.
** <li> A prefix string written at the beginning of every
**      line of trace output.  If NULL, then tracing is
**      turned off.
** </ul>
**
** Outputs:
** None.
*/
void ParseTrace(FILE *TraceFILE, char *zTracePrompt){
  yyTraceFILE = TraceFILE;
  yyTracePrompt = zTracePrompt;
  if( yyTraceFILE==0 ) yyTracePrompt = 0;
  else if( yyTracePrompt==0 ) yyTraceFILE = 0;
}
#endif /* NDEBUG */

#ifndef NDEBUG
/* For tracing shifts, the names of all terminals and nonterminals
** are required.  The following table supplies these names */
static const char *yyTokenName[] = { 
  "$",             "NUM",           "PLUS",          "MINUS",       
  "DIVIDE",        "TIMES",         "error",         "expr",        
  "program",     
};
#endif /* NDEBUG */

#ifndef NDEBUG
/* For tracing reduce actions, the names of all rules are required.
*/
static const char *yyRuleName[] = {
 /*   0 */ "program ::= expr",
 /*   1 */ "expr ::= expr MINUS expr",
 /*   2 */ "expr ::= expr PLUS expr",
 /*   3 */ "expr ::= expr TIMES expr",
 /*   4 */ "expr ::= expr DIVIDE expr",
 /*   5 */ "expr ::= NUM",
};
#endif /* NDEBUG */

/*
** This function returns the symbolic name associated with a token
** value.
*/
const char *ParseTokenName(int tokenType){
#ifndef NDEBUG
  if( tokenType>0 && tokenType<(sizeof(yyTokenName)/sizeof(yyTokenName[0])) ){
    return yyTokenName[tokenType];
  }else{
    return "Unknown";
  }
#else
  return "";
#endif
}

/* 
** This function allocates a new parser.
** The only argument is a pointer to a function which works like
** malloc.
**
** Inputs:
** A pointer to the function used to allocate memory.
**
** Outputs:
** A pointer to a parser.  This pointer is used in subsequent calls
** to Parse and ParseFree.
*/
void *ParseAlloc(void *(*mallocProc)(size_t)){
  yyParser *pParser;
  pParser = (yyParser*)(*mallocProc)( (size_t)sizeof(yyParser) );
  if( pParser ){
    pParser->yyidx = -1;
  }
  return pParser;
}

/* The following function deletes the value associated with a
** symbol.  The symbol can be either a terminal or nonterminal.
** "yymajor" is the symbol code, and "yypminor" is a pointer to
** the value.
*/
static void yy_destructor(YYCODETYPE yymajor, YYMINORTYPE *yypminor){
  switch( yymajor ){
    /* Here is inserted the actions which take place when a
    ** terminal or non-terminal is destroyed.  This can happen
    ** when the symbol is popped from the stack during a
    ** reduce or during error processing or when a parser is 
    ** being destroyed before it is finished parsing.
    **
    ** Note: during a reduce, the only symbols destroyed are those
    ** which appear on the RHS of the rule, but which are not used
    ** inside the C code.
    */
    default:  break;   /* If no destructor action specified: do nothing */
  }
}

/*
** Pop the parser's stack once.
**
** If there is a destructor routine associated with the token which
** is popped from the stack, then call it.
**
** Return the major token number for the symbol popped.
*/
static int yy_pop_parser_stack(yyParser *pParser){
  YYCODETYPE yymajor;
  yyStackEntry *yytos = &pParser->yystack[pParser->yyidx];

  if( pParser->yyidx<0 ) return 0;
#ifndef NDEBUG
  if( yyTraceFILE && pParser->yyidx>=0 ){
    fprintf(yyTraceFILE,"%sPopping %s\n",
      yyTracePrompt,
      yyTokenName[yytos->major]);
  }
#endif
  yymajor = yytos->major;
  yy_destructor( yymajor, &yytos->minor);
  pParser->yyidx--;
  return yymajor;
}

/* 
** Deallocate and destroy a parser.  Destructors are all called for
** all stack elements before shutting the parser down.
**
** Inputs:
** <ul>
** <li>  A pointer to the parser.  This should be a pointer
**       obtained from ParseAlloc.
** <li>  A pointer to a function used to reclaim memory obtained
**       from malloc.
** </ul>
*/
void ParseFree(
  void *p,                    /* The parser to be deleted */
  void (*freeProc)(void*)     /* Function used to reclaim memory */
){
  yyParser *pParser = (yyParser*)p;
  if( pParser==0 ) return;
  while( pParser->yyidx>=0 ) yy_pop_parser_stack(pParser);
  (*freeProc)((void*)pParser);
}

/*
** Find the appropriate action for a parser given the terminal
** look-ahead token iLookAhead.
**
** If the look-ahead token is YYNOCODE, then check to see if the action is
** independent of the look-ahead.  If it is, return the action, otherwise
** return YY_NO_ACTION.
*/
static int yy_find_shift_action(
  yyParser *pParser,        /* The parser */
  int iLookAhead            /* The look-ahead token */
){
  int i;
  int stateno = pParser->yystack[pParser->yyidx].stateno;
 
  /* if( pParser->yyidx<0 ) return YY_NO_ACTION;  */
  i = yy_shift_ofst[stateno];
  if( i==YY_SHIFT_USE_DFLT ){
    return yy_default[stateno];
  }
  if( iLookAhead==YYNOCODE ){
    return YY_NO_ACTION;
  }
  i += iLookAhead;
  if( i<0 || i>=YY_SZ_ACTTAB || yy_lookahead[i]!=iLookAhead ){
#ifdef YYFALLBACK
    int iFallback;            /* Fallback token */
    if( iLookAhead<sizeof(yyFallback)/sizeof(yyFallback[0])
           && (iFallback = yyFallback[iLookAhead])!=0 ){
#ifndef NDEBUG
      if( yyTraceFILE ){
        fprintf(yyTraceFILE, "%sFALLBACK %s => %s\n",
           yyTracePrompt, yyTokenName[iLookAhead], yyTokenName[iFallback]);
      }