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lemon/lemon.c  view on Meta::CPAN

  WAITING_FOR_DATATYPE_SYMBOL,
  WAITING_FOR_FALLBACK_ID,
  WAITING_FOR_WILDCARD_ID,
  WAITING_FOR_CLASS_ID,
  WAITING_FOR_CLASS_TOKEN,
  WAITING_FOR_TOKEN_NAME
};
struct pstate {
  char *filename;       /* Name of the input file */
  int tokenlineno;      /* Linenumber at which current token starts */
  int errorcnt;         /* Number of errors so far */
  char *tokenstart;     /* Text of current token */
  struct lemon *gp;     /* Global state vector */
  enum e_state state;        /* The state of the parser */
  struct symbol *fallback;   /* The fallback token */
  struct symbol *tkclass;    /* Token class symbol */
  struct symbol *lhs;        /* Left-hand side of current rule */
  const char *lhsalias;      /* Alias for the LHS */
  int nrhs;                  /* Number of right-hand side symbols seen */
  struct symbol *rhs[MAXRHS];  /* RHS symbols */
  const char *alias[MAXRHS]; /* Aliases for each RHS symbol (or NULL) */
  struct rule *prevrule;     /* Previous rule parsed */
  const char *declkeyword;   /* Keyword of a declaration */
  char **declargslot;        /* Where the declaration argument should be put */
  int insertLineMacro;       /* Add #line before declaration insert */
  int *decllinenoslot;       /* Where to write declaration line number */
  enum e_assoc declassoc;    /* Assign this association to decl arguments */
  int preccounter;           /* Assign this precedence to decl arguments */
  struct rule *firstrule;    /* Pointer to first rule in the grammar */
  struct rule *lastrule;     /* Pointer to the most recently parsed rule */
};

/* Parse a single token */
static void parseonetoken(struct pstate *psp)
{
  const char *x;
  x = Strsafe(psp->tokenstart);     /* Save the token permanently */
#if 0
  printf("%s:%d: Token=[%s] state=%d\n",psp->filename,psp->tokenlineno,
    x,psp->state);
#endif
  switch( psp->state ){
    case INITIALIZE:
      psp->prevrule = 0;
      psp->preccounter = 0;
      psp->firstrule = psp->lastrule = 0;
      psp->gp->nrule = 0;
      /* fall through */
    case WAITING_FOR_DECL_OR_RULE:
      if( x[0]=='%' ){
        psp->state = WAITING_FOR_DECL_KEYWORD;
      }else if( ISLOWER(x[0]) ){
        psp->lhs = Symbol_new(x);
        psp->nrhs = 0;
        psp->lhsalias = 0;
        psp->state = WAITING_FOR_ARROW;
      }else if( x[0]=='{' ){
        if( psp->prevrule==0 ){
          ErrorMsg(psp->filename,psp->tokenlineno,
            "There is no prior rule upon which to attach the code "
            "fragment which begins on this line.");
          psp->errorcnt++;
        }else if( psp->prevrule->code!=0 ){
          ErrorMsg(psp->filename,psp->tokenlineno,
            "Code fragment beginning on this line is not the first "
            "to follow the previous rule.");
          psp->errorcnt++;
        }else if( strcmp(x, "{NEVER-REDUCE")==0 ){
          psp->prevrule->neverReduce = 1;
        }else{
          psp->prevrule->line = psp->tokenlineno;
          psp->prevrule->code = &x[1];
          psp->prevrule->noCode = 0;
        }
      }else if( x[0]=='[' ){
        psp->state = PRECEDENCE_MARK_1;
      }else{
        ErrorMsg(psp->filename,psp->tokenlineno,
          "Token \"%s\" should be either \"%%\" or a nonterminal name.",
          x);
        psp->errorcnt++;
      }
      break;
    case PRECEDENCE_MARK_1:
      if( !ISUPPER(x[0]) ){
        ErrorMsg(psp->filename,psp->tokenlineno,
          "The precedence symbol must be a terminal.");
        psp->errorcnt++;
      }else if( psp->prevrule==0 ){
        ErrorMsg(psp->filename,psp->tokenlineno,
          "There is no prior rule to assign precedence \"[%s]\".",x);
        psp->errorcnt++;
      }else if( psp->prevrule->precsym!=0 ){
        ErrorMsg(psp->filename,psp->tokenlineno,
          "Precedence mark on this line is not the first "
          "to follow the previous rule.");
        psp->errorcnt++;
      }else{
        psp->prevrule->precsym = Symbol_new(x);
      }
      psp->state = PRECEDENCE_MARK_2;
      break;
    case PRECEDENCE_MARK_2:
      if( x[0]!=']' ){
        ErrorMsg(psp->filename,psp->tokenlineno,
          "Missing \"]\" on precedence mark.");
        psp->errorcnt++;
      }
      psp->state = WAITING_FOR_DECL_OR_RULE;
      break;
    case WAITING_FOR_ARROW:
      if( x[0]==':' && x[1]==':' && x[2]=='=' ){
        psp->state = IN_RHS;
      }else if( x[0]=='(' ){
        psp->state = LHS_ALIAS_1;
      }else{
        ErrorMsg(psp->filename,psp->tokenlineno,
          "Expected to see a \":\" following the LHS symbol \"%s\".",
          psp->lhs->name);
        psp->errorcnt++;
        psp->state = RESYNC_AFTER_RULE_ERROR;
      }
      break;
    case LHS_ALIAS_1:
      if( ISALPHA(x[0]) ){