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Overview
Comment:More agressive use of /*A-overwrites-X*/ in the parser. Fix an off-by-one error in parser stack overflow detection.
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SHA1: 417e777701bbf4bd67626d4ca3bc2c5d847f6cd0
User & Date: drh 2016-02-17 12:34:03
Context
2016-02-17
13:24
Enhance Lemon to generate more compact and efficient code for yy_reduce(). Update the main SQL grammar to take advantage of the new capabilities. check-in: 53fd040c user: drh tags: trunk
12:34
More agressive use of /*A-overwrites-X*/ in the parser. Fix an off-by-one error in parser stack overflow detection. Closed-Leaf check-in: 417e7777 user: drh tags: parser-performance
04:33
Enhance Lemon so that if reduce code contains a comment of the form "/*A-overwrites-X*/" then a LHS label A is allowed to overwrite the RHS label X. check-in: 5cfe9545 user: drh tags: parser-performance
Changes
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Changes to src/parse.y.

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  v.pExpr = sqlite3PExpr(pParse, TK_UMINUS, X.pExpr, 0, 0);
  v.zStart = A.z;
  v.zEnd = X.zEnd;
  sqlite3AddDefaultValue(pParse,&v);
}
ccons ::= DEFAULT id(X).              {
  ExprSpan v;
  spanExpr(&v, pParse, TK_STRING, &X);
  sqlite3AddDefaultValue(pParse,&v);
}

// In addition to the type name, we also care about the primary key and
// UNIQUE constraints.
//
ccons ::= NULL onconf.
................................................................................
%type multiselect_op {int}
multiselect_op(A) ::= UNION(OP).             {A = @OP; /*A-overwrites-OP*/}
multiselect_op(A) ::= UNION ALL.             {A = TK_ALL;}
multiselect_op(A) ::= EXCEPT|INTERSECT(OP).  {A = @OP; /*A-overwrites-OP*/}
%endif SQLITE_OMIT_COMPOUND_SELECT
oneselect(A) ::= SELECT(S) distinct(D) selcollist(W) from(X) where_opt(Y)
                 groupby_opt(P) having_opt(Q) orderby_opt(Z) limit_opt(L). {



  A = sqlite3SelectNew(pParse,W,X,Y,P,Q,Z,D,L.pLimit,L.pOffset);
#if SELECTTRACE_ENABLED
  /* Populate the Select.zSelName[] string that is used to help with
  ** query planner debugging, to differentiate between multiple Select
  ** objects in a complex query.
  **
  ** If the SELECT keyword is immediately followed by a C-style comment
  ** then extract the first few alphanumeric characters from within that
  ** comment to be the zSelName value.  Otherwise, the label is #N where
  ** is an integer that is incremented with each SELECT statement seen.
  */
  if( A!=0 ){
    const char *z = S.z+6;
    int i;
    sqlite3_snprintf(sizeof(A->zSelName), A->zSelName, "#%d",
                     ++pParse->nSelect);
    while( z[0]==' ' ) z++;
    if( z[0]=='/' && z[1]=='*' ){
      z += 2;
      while( z[0]==' ' ) z++;
................................................................................
    pOut->zEnd = &pEnd->z[pEnd->n];
  }

  /* Construct a new Expr object from a single identifier.  Use the
  ** new Expr to populate pOut.  Set the span of pOut to be the identifier
  ** that created the expression.
  */
  static void spanExpr(ExprSpan *pOut, Parse *pParse, int op, Token *pValue){
    pOut->pExpr = sqlite3PExpr(pParse, op, 0, 0, pValue);
    pOut->zStart = pValue->z;
    pOut->zEnd = &pValue->z[pValue->n];
  }
}

expr(A) ::= term(A).
expr(A) ::= LP(B) expr(X) RP(E). {A.pExpr = X.pExpr; spanSet(&A,&B,&E);}

term(A) ::= NULL(X).             {spanExpr(&A, pParse, @X, &X);}
expr(A) ::= id(X).               {spanExpr(&A, pParse, TK_ID, &X);}
expr(A) ::= JOIN_KW(X).          {spanExpr(&A, pParse, TK_ID, &X);}
expr(A) ::= nm(X) DOT nm(Y). {
  Expr *temp1 = sqlite3PExpr(pParse, TK_ID, 0, 0, &X);
  Expr *temp2 = sqlite3PExpr(pParse, TK_ID, 0, 0, &Y);
  spanSet(&A,&X,&Y); /*A-overwrites-X*/
  A.pExpr = sqlite3PExpr(pParse, TK_DOT, temp1, temp2, 0);
}
expr(A) ::= nm(X) DOT nm(Y) DOT nm(Z). {
................................................................................
  Expr *temp1 = sqlite3PExpr(pParse, TK_ID, 0, 0, &X);
  Expr *temp2 = sqlite3PExpr(pParse, TK_ID, 0, 0, &Y);
  Expr *temp3 = sqlite3PExpr(pParse, TK_ID, 0, 0, &Z);
  Expr *temp4 = sqlite3PExpr(pParse, TK_DOT, temp2, temp3, 0);
  spanSet(&A,&X,&Z); /*A-overwrites-X*/
  A.pExpr = sqlite3PExpr(pParse, TK_DOT, temp1, temp4, 0);
}
term(A) ::= INTEGER|FLOAT|BLOB(X).  {spanExpr(&A, pParse, @X, &X);}
term(A) ::= STRING(X).              {spanExpr(&A, pParse, @X, &X);}
expr(A) ::= VARIABLE(X).     {

  if( X.n>=2 && X.z[0]=='#' && sqlite3Isdigit(X.z[1]) ){
    /* When doing a nested parse, one can include terms in an expression
    ** that look like this:   #1 #2 ...  These terms refer to registers
    ** in the virtual machine.  #N is the N-th register. */

    if( pParse->nested==0 ){
      sqlite3ErrorMsg(pParse, "near \"%T\": syntax error", &X);
      A.pExpr = 0;
    }else{
      A.pExpr = sqlite3PExpr(pParse, TK_REGISTER, 0, 0, &X);
      if( A.pExpr ) sqlite3GetInt32(&X.z[1], &A.pExpr->iTable);
    }
  }else{
    spanExpr(&A, pParse, TK_VARIABLE, &X);
    sqlite3ExprAssignVarNumber(pParse, A.pExpr);
  }
  spanSet(&A, &X, &X);
}
expr(A) ::= expr(A) COLLATE ids(C). {
  A.pExpr = sqlite3ExprAddCollateToken(pParse, A.pExpr, &C, 1);
  A.zEnd = &C.z[C.n];
}
%ifndef SQLITE_OMIT_CAST
expr(A) ::= CAST(X) LP expr(E) AS typetoken(T) RP(Y). {

  A.pExpr = sqlite3PExpr(pParse, TK_CAST, E.pExpr, 0, &T);
  spanSet(&A,&X,&Y);
}
%endif  SQLITE_OMIT_CAST
expr(A) ::= id(X) LP distinct(D) exprlist(Y) RP(E). {
  if( Y && Y->nExpr>pParse->db->aLimit[SQLITE_LIMIT_FUNCTION_ARG] ){
    sqlite3ErrorMsg(pParse, "too many arguments on function %T", &X);
  }
  A.pExpr = sqlite3ExprFunction(pParse, Y, &X);
................................................................................
  static void spanUnaryPrefix(
    ExprSpan *pOut,        /* Write the new expression node here */
    Parse *pParse,         /* Parsing context to record errors */
    int op,                /* The operator */
    ExprSpan *pOperand,    /* The operand */
    Token *pPreOp         /* The operand token for setting the span */
  ){
    pOut->pExpr = sqlite3PExpr(pParse, op, pOperand->pExpr, 0, 0);
    pOut->zStart = pPreOp->z;

    pOut->zEnd = pOperand->zEnd;
  }
}




expr(A) ::= NOT(B) expr(X).    {spanUnaryPrefix(&A,pParse,@B,&X,&B);}
expr(A) ::= BITNOT(B) expr(X). {spanUnaryPrefix(&A,pParse,@B,&X,&B);}

expr(A) ::= MINUS(B) expr(X). [BITNOT]
                               {spanUnaryPrefix(&A,pParse,TK_UMINUS,&X,&B);}
expr(A) ::= PLUS(B) expr(X). [BITNOT]
                               {spanUnaryPrefix(&A,pParse,TK_UPLUS,&X,&B);}

%type between_op {int}
between_op(A) ::= BETWEEN.     {A = 0;}
between_op(A) ::= NOT BETWEEN. {A = 1;}
expr(A) ::= expr(A) between_op(N) expr(X) AND expr(Y). [BETWEEN] {
  ExprList *pList = sqlite3ExprListAppend(pParse,0, X.pExpr);
  pList = sqlite3ExprListAppend(pParse,pList, Y.pExpr);
................................................................................
        sqlite3ExprListDelete(pParse->db, Y);
      }
      exprNot(pParse, N, &A);
    }
    A.zEnd = &E.z[E.n];
  }
  expr(A) ::= LP(B) select(X) RP(E). {

    A.pExpr = sqlite3PExpr(pParse, TK_SELECT, 0, 0, 0);
    if( A.pExpr ){
      A.pExpr->x.pSelect = X;
      ExprSetProperty(A.pExpr, EP_xIsSelect|EP_Subquery);
      sqlite3ExprSetHeightAndFlags(pParse, A.pExpr);
    }else{
      sqlite3SelectDelete(pParse->db, X);
    }
    A.zStart = B.z;
    A.zEnd = &E.z[E.n];
  }
  expr(A) ::= expr(A) in_op(N) LP select(Y) RP(E).  [IN] {
    A.pExpr = sqlite3PExpr(pParse, TK_IN, A.pExpr, 0, 0);
    if( A.pExpr ){
      A.pExpr->x.pSelect = Y;
      ExprSetProperty(A.pExpr, EP_xIsSelect|EP_Subquery);
      sqlite3ExprSetHeightAndFlags(pParse, A.pExpr);
................................................................................
    }else{
      sqlite3SrcListDelete(pParse->db, pSrc);
    }
    exprNot(pParse, N, &A);
    A.zEnd = Z.z ? &Z.z[Z.n] : &Y.z[Y.n];
  }
  expr(A) ::= EXISTS(B) LP select(Y) RP(E). {


    Expr *p = A.pExpr = sqlite3PExpr(pParse, TK_EXISTS, 0, 0, 0);
    if( p ){
      p->x.pSelect = Y;
      ExprSetProperty(p, EP_xIsSelect|EP_Subquery);
      sqlite3ExprSetHeightAndFlags(pParse, p);
    }else{
      sqlite3SelectDelete(pParse->db, Y);
    }
    A.zStart = B.z;
    A.zEnd = &E.z[E.n];
  }
%endif SQLITE_OMIT_SUBQUERY

/* CASE expressions */
expr(A) ::= CASE(C) case_operand(X) case_exprlist(Y) case_else(Z) END(E). {

  A.pExpr = sqlite3PExpr(pParse, TK_CASE, X, 0, 0);
  if( A.pExpr ){
    A.pExpr->x.pList = Z ? sqlite3ExprListAppend(pParse,Y,Z) : Y;
    sqlite3ExprSetHeightAndFlags(pParse, A.pExpr);
  }else{
    sqlite3ExprListDelete(pParse->db, Y);
    sqlite3ExprDelete(pParse->db, Z);
  }
  A.zStart = C.z;
  A.zEnd = &E.z[E.n];
}
%type case_exprlist {ExprList*}
%destructor case_exprlist {sqlite3ExprListDelete(pParse->db, $$);}
case_exprlist(A) ::= case_exprlist(A) WHEN expr(Y) THEN expr(Z). {
  A = sqlite3ExprListAppend(pParse,A, Y.pExpr);
  A = sqlite3ExprListAppend(pParse,A, Z.pExpr);
}
................................................................................
// UPDATE 
trigger_cmd(A) ::=
   UPDATE orconf(R) trnm(X) tridxby SET setlist(Y) where_opt(Z).  
   { A = sqlite3TriggerUpdateStep(pParse->db, &X, Y, Z, R); }

// INSERT
trigger_cmd(A) ::= insert_cmd(R) INTO trnm(X) idlist_opt(F) select(S).
               {A = sqlite3TriggerInsertStep(pParse->db, &X, F, S, R);}

// DELETE
trigger_cmd(A) ::= DELETE FROM trnm(X) tridxby where_opt(Y).
               {A = sqlite3TriggerDeleteStep(pParse->db, &X, Y);}

// SELECT
trigger_cmd(A) ::= select(X).







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  v.pExpr = sqlite3PExpr(pParse, TK_UMINUS, X.pExpr, 0, 0);
  v.zStart = A.z;
  v.zEnd = X.zEnd;
  sqlite3AddDefaultValue(pParse,&v);
}
ccons ::= DEFAULT id(X).              {
  ExprSpan v;
  spanExpr(&v, pParse, TK_STRING, X);
  sqlite3AddDefaultValue(pParse,&v);
}

// In addition to the type name, we also care about the primary key and
// UNIQUE constraints.
//
ccons ::= NULL onconf.
................................................................................
%type multiselect_op {int}
multiselect_op(A) ::= UNION(OP).             {A = @OP; /*A-overwrites-OP*/}
multiselect_op(A) ::= UNION ALL.             {A = TK_ALL;}
multiselect_op(A) ::= EXCEPT|INTERSECT(OP).  {A = @OP; /*A-overwrites-OP*/}
%endif SQLITE_OMIT_COMPOUND_SELECT
oneselect(A) ::= SELECT(S) distinct(D) selcollist(W) from(X) where_opt(Y)
                 groupby_opt(P) having_opt(Q) orderby_opt(Z) limit_opt(L). {
#if SELECTTRACE_ENABLED
  Token s = S; /*A-overwrites-S*/
#endif
  A = sqlite3SelectNew(pParse,W,X,Y,P,Q,Z,D,L.pLimit,L.pOffset);
#if SELECTTRACE_ENABLED
  /* Populate the Select.zSelName[] string that is used to help with
  ** query planner debugging, to differentiate between multiple Select
  ** objects in a complex query.
  **
  ** If the SELECT keyword is immediately followed by a C-style comment
  ** then extract the first few alphanumeric characters from within that
  ** comment to be the zSelName value.  Otherwise, the label is #N where
  ** is an integer that is incremented with each SELECT statement seen.
  */
  if( A!=0 ){
    const char *z = s.z+6;
    int i;
    sqlite3_snprintf(sizeof(A->zSelName), A->zSelName, "#%d",
                     ++pParse->nSelect);
    while( z[0]==' ' ) z++;
    if( z[0]=='/' && z[1]=='*' ){
      z += 2;
      while( z[0]==' ' ) z++;
................................................................................
    pOut->zEnd = &pEnd->z[pEnd->n];
  }

  /* Construct a new Expr object from a single identifier.  Use the
  ** new Expr to populate pOut.  Set the span of pOut to be the identifier
  ** that created the expression.
  */
  static void spanExpr(ExprSpan *pOut, Parse *pParse, int op, Token t){
    pOut->pExpr = sqlite3PExpr(pParse, op, 0, 0, &t);
    pOut->zStart = t.z;
    pOut->zEnd = &t.z[t.n];
  }
}

expr(A) ::= term(A).
expr(A) ::= LP(B) expr(X) RP(E).
            {spanSet(&A,&B,&E); /*A-overwrites-B*/  A.pExpr = X.pExpr;}
term(A) ::= NULL(X).        {spanExpr(&A,pParse,@X,X);/*A-overwrites-X*/}
expr(A) ::= id(X).          {spanExpr(&A,pParse,TK_ID,X); /*A-overwrites-X*/}
expr(A) ::= JOIN_KW(X).     {spanExpr(&A,pParse,TK_ID,X); /*A-overwrites-X*/}
expr(A) ::= nm(X) DOT nm(Y). {
  Expr *temp1 = sqlite3PExpr(pParse, TK_ID, 0, 0, &X);
  Expr *temp2 = sqlite3PExpr(pParse, TK_ID, 0, 0, &Y);
  spanSet(&A,&X,&Y); /*A-overwrites-X*/
  A.pExpr = sqlite3PExpr(pParse, TK_DOT, temp1, temp2, 0);
}
expr(A) ::= nm(X) DOT nm(Y) DOT nm(Z). {
................................................................................
  Expr *temp1 = sqlite3PExpr(pParse, TK_ID, 0, 0, &X);
  Expr *temp2 = sqlite3PExpr(pParse, TK_ID, 0, 0, &Y);
  Expr *temp3 = sqlite3PExpr(pParse, TK_ID, 0, 0, &Z);
  Expr *temp4 = sqlite3PExpr(pParse, TK_DOT, temp2, temp3, 0);
  spanSet(&A,&X,&Z); /*A-overwrites-X*/
  A.pExpr = sqlite3PExpr(pParse, TK_DOT, temp1, temp4, 0);
}
term(A) ::= INTEGER|FLOAT|BLOB(X). {spanExpr(&A,pParse,@X,X);/*A-overwrites-X*/}
term(A) ::= STRING(X).             {spanExpr(&A,pParse,@X,X);/*A-overwrites-X*/}
expr(A) ::= VARIABLE(X).     {
  Token t = X; /*A-overwrites-X*/
  if( t.n>=2 && t.z[0]=='#' && sqlite3Isdigit(t.z[1]) ){
    /* When doing a nested parse, one can include terms in an expression
    ** that look like this:   #1 #2 ...  These terms refer to registers
    ** in the virtual machine.  #N is the N-th register. */
    spanSet(&A, &t, &t);
    if( pParse->nested==0 ){
      sqlite3ErrorMsg(pParse, "near \"%T\": syntax error", &t);
      A.pExpr = 0;
    }else{
      A.pExpr = sqlite3PExpr(pParse, TK_REGISTER, 0, 0, &t);
      if( A.pExpr ) sqlite3GetInt32(&t.z[1], &A.pExpr->iTable);
    }
  }else{
    spanExpr(&A, pParse, TK_VARIABLE, t);
    sqlite3ExprAssignVarNumber(pParse, A.pExpr);
  }

}
expr(A) ::= expr(A) COLLATE ids(C). {
  A.pExpr = sqlite3ExprAddCollateToken(pParse, A.pExpr, &C, 1);
  A.zEnd = &C.z[C.n];
}
%ifndef SQLITE_OMIT_CAST
expr(A) ::= CAST(X) LP expr(E) AS typetoken(T) RP(Y). {
  spanSet(&A,&X,&Y); /*A-overwrites-X*/
  A.pExpr = sqlite3PExpr(pParse, TK_CAST, E.pExpr, 0, &T);

}
%endif  SQLITE_OMIT_CAST
expr(A) ::= id(X) LP distinct(D) exprlist(Y) RP(E). {
  if( Y && Y->nExpr>pParse->db->aLimit[SQLITE_LIMIT_FUNCTION_ARG] ){
    sqlite3ErrorMsg(pParse, "too many arguments on function %T", &X);
  }
  A.pExpr = sqlite3ExprFunction(pParse, Y, &X);
................................................................................
  static void spanUnaryPrefix(
    ExprSpan *pOut,        /* Write the new expression node here */
    Parse *pParse,         /* Parsing context to record errors */
    int op,                /* The operator */
    ExprSpan *pOperand,    /* The operand */
    Token *pPreOp         /* The operand token for setting the span */
  ){

    pOut->zStart = pPreOp->z;
    pOut->pExpr = sqlite3PExpr(pParse, op, pOperand->pExpr, 0, 0);
    pOut->zEnd = pOperand->zEnd;
  }
}



expr(A) ::= NOT(B) expr(X).  
              {spanUnaryPrefix(&A,pParse,@B,&X,&B);/*A-overwrites-B*/}
expr(A) ::= BITNOT(B) expr(X).
              {spanUnaryPrefix(&A,pParse,@B,&X,&B);/*A-overwrites-B*/}
expr(A) ::= MINUS(B) expr(X). [BITNOT]
              {spanUnaryPrefix(&A,pParse,TK_UMINUS,&X,&B);/*A-overwrites-B*/}
expr(A) ::= PLUS(B) expr(X). [BITNOT]
              {spanUnaryPrefix(&A,pParse,TK_UPLUS,&X,&B);/*A-overwrites-B*/}

%type between_op {int}
between_op(A) ::= BETWEEN.     {A = 0;}
between_op(A) ::= NOT BETWEEN. {A = 1;}
expr(A) ::= expr(A) between_op(N) expr(X) AND expr(Y). [BETWEEN] {
  ExprList *pList = sqlite3ExprListAppend(pParse,0, X.pExpr);
  pList = sqlite3ExprListAppend(pParse,pList, Y.pExpr);
................................................................................
        sqlite3ExprListDelete(pParse->db, Y);
      }
      exprNot(pParse, N, &A);
    }
    A.zEnd = &E.z[E.n];
  }
  expr(A) ::= LP(B) select(X) RP(E). {
    spanSet(&A,&B,&E); /*A-overwrites-B*/
    A.pExpr = sqlite3PExpr(pParse, TK_SELECT, 0, 0, 0);
    if( A.pExpr ){
      A.pExpr->x.pSelect = X;
      ExprSetProperty(A.pExpr, EP_xIsSelect|EP_Subquery);
      sqlite3ExprSetHeightAndFlags(pParse, A.pExpr);
    }else{
      sqlite3SelectDelete(pParse->db, X);
    }


  }
  expr(A) ::= expr(A) in_op(N) LP select(Y) RP(E).  [IN] {
    A.pExpr = sqlite3PExpr(pParse, TK_IN, A.pExpr, 0, 0);
    if( A.pExpr ){
      A.pExpr->x.pSelect = Y;
      ExprSetProperty(A.pExpr, EP_xIsSelect|EP_Subquery);
      sqlite3ExprSetHeightAndFlags(pParse, A.pExpr);
................................................................................
    }else{
      sqlite3SrcListDelete(pParse->db, pSrc);
    }
    exprNot(pParse, N, &A);
    A.zEnd = Z.z ? &Z.z[Z.n] : &Y.z[Y.n];
  }
  expr(A) ::= EXISTS(B) LP select(Y) RP(E). {
    Expr *p;
    spanSet(&A,&B,&E); /*A-overwrites-B*/
    p = A.pExpr = sqlite3PExpr(pParse, TK_EXISTS, 0, 0, 0);
    if( p ){
      p->x.pSelect = Y;
      ExprSetProperty(p, EP_xIsSelect|EP_Subquery);
      sqlite3ExprSetHeightAndFlags(pParse, p);
    }else{
      sqlite3SelectDelete(pParse->db, Y);
    }


  }
%endif SQLITE_OMIT_SUBQUERY

/* CASE expressions */
expr(A) ::= CASE(C) case_operand(X) case_exprlist(Y) case_else(Z) END(E). {
  spanSet(&A,&C,&E);  /*A-overwrites-C*/
  A.pExpr = sqlite3PExpr(pParse, TK_CASE, X, 0, 0);
  if( A.pExpr ){
    A.pExpr->x.pList = Z ? sqlite3ExprListAppend(pParse,Y,Z) : Y;
    sqlite3ExprSetHeightAndFlags(pParse, A.pExpr);
  }else{
    sqlite3ExprListDelete(pParse->db, Y);
    sqlite3ExprDelete(pParse->db, Z);
  }


}
%type case_exprlist {ExprList*}
%destructor case_exprlist {sqlite3ExprListDelete(pParse->db, $$);}
case_exprlist(A) ::= case_exprlist(A) WHEN expr(Y) THEN expr(Z). {
  A = sqlite3ExprListAppend(pParse,A, Y.pExpr);
  A = sqlite3ExprListAppend(pParse,A, Z.pExpr);
}
................................................................................
// UPDATE 
trigger_cmd(A) ::=
   UPDATE orconf(R) trnm(X) tridxby SET setlist(Y) where_opt(Z).  
   {A = sqlite3TriggerUpdateStep(pParse->db, &X, Y, Z, R);}

// INSERT
trigger_cmd(A) ::= insert_cmd(R) INTO trnm(X) idlist_opt(F) select(S).
   {A = sqlite3TriggerInsertStep(pParse->db, &X, F, S, R);/*A-overwrites-R*/}

// DELETE
trigger_cmd(A) ::= DELETE FROM trnm(X) tridxby where_opt(Y).
   {A = sqlite3TriggerDeleteStep(pParse->db, &X, Y);}

// SELECT
trigger_cmd(A) ::= select(X).

Changes to tool/lemon.c.

3473
3474
3475
3476
3477
3478
3479

3480
3481
3482
3483
3484
3485
3486
....
3545
3546
3547
3548
3549
3550
3551

3552
3553
3554
3555
3556
3557
3558
....
3559
3560
3561
3562
3563
3564
3565





3566
3567
3568
3569
3570
3571
3572
3573
** Return 1 if the expanded code requires that "yylhsminor" local variable
** to be defined.
*/
PRIVATE int translate_code(struct lemon *lemp, struct rule *rp){
  char *cp, *xp;
  int i;
  int rc = 0;            /* True if yylhsminor is used */

  const char *zSkip = 0; /* The zOvwrt comment within rp->code, or NULL */
  char lhsused = 0;      /* True if the LHS element has been used */
  char lhsdirect;        /* True if LHS writes directly into stack */
  char used[MAXRHS];     /* True for each RHS element which is used */
  char zLhs[50];         /* Convert the LHS symbol into this string */
  char zOvwrt[900];      /* Comment that to allow LHS to overwrite RHS */

................................................................................
  append_str(0,0,0,0);

  /* This const cast is wrong but harmless, if we're careful. */
  for(cp=(char *)rp->code; *cp; cp++){
    if( cp==zSkip ){
      append_str(zOvwrt,0,0,0);
      cp += lemonStrlen(zOvwrt)-1;

      continue;
    }
    if( ISALPHA(*cp) && (cp==rp->code || (!ISALNUM(cp[-1]) && cp[-1]!='_')) ){
      char saved;
      for(xp= &cp[1]; ISALNUM(*xp) || *xp=='_'; xp++);
      saved = *xp;
      *xp = 0;
................................................................................
      if( rp->lhsalias && strcmp(cp,rp->lhsalias)==0 ){
        append_str(zLhs,0,0,0);
        cp = xp;
        lhsused = 1;
      }else{
        for(i=0; i<rp->nrhs; i++){
          if( rp->rhsalias[i] && strcmp(cp,rp->rhsalias[i])==0 ){





            if( cp!=rp->code && cp[-1]=='@' ){
              /* If the argument is of the form @X then substituted
              ** the token number of X, not the value of X */
              append_str("yymsp[%d].major",-1,i-rp->nrhs+1,0);
            }else{
              struct symbol *sp = rp->rhs[i];
              int dtnum;
              if( sp->type==MULTITERMINAL ){







>







 







>







 







>
>
>
>
>
|







3473
3474
3475
3476
3477
3478
3479
3480
3481
3482
3483
3484
3485
3486
3487
....
3546
3547
3548
3549
3550
3551
3552
3553
3554
3555
3556
3557
3558
3559
3560
....
3561
3562
3563
3564
3565
3566
3567
3568
3569
3570
3571
3572
3573
3574
3575
3576
3577
3578
3579
3580
** Return 1 if the expanded code requires that "yylhsminor" local variable
** to be defined.
*/
PRIVATE int translate_code(struct lemon *lemp, struct rule *rp){
  char *cp, *xp;
  int i;
  int rc = 0;            /* True if yylhsminor is used */
  int dontUseRhs0 = 0;   /* If true, use of left-most RHS label is illegal */
  const char *zSkip = 0; /* The zOvwrt comment within rp->code, or NULL */
  char lhsused = 0;      /* True if the LHS element has been used */
  char lhsdirect;        /* True if LHS writes directly into stack */
  char used[MAXRHS];     /* True for each RHS element which is used */
  char zLhs[50];         /* Convert the LHS symbol into this string */
  char zOvwrt[900];      /* Comment that to allow LHS to overwrite RHS */

................................................................................
  append_str(0,0,0,0);

  /* This const cast is wrong but harmless, if we're careful. */
  for(cp=(char *)rp->code; *cp; cp++){
    if( cp==zSkip ){
      append_str(zOvwrt,0,0,0);
      cp += lemonStrlen(zOvwrt)-1;
      dontUseRhs0 = 1;
      continue;
    }
    if( ISALPHA(*cp) && (cp==rp->code || (!ISALNUM(cp[-1]) && cp[-1]!='_')) ){
      char saved;
      for(xp= &cp[1]; ISALNUM(*xp) || *xp=='_'; xp++);
      saved = *xp;
      *xp = 0;
................................................................................
      if( rp->lhsalias && strcmp(cp,rp->lhsalias)==0 ){
        append_str(zLhs,0,0,0);
        cp = xp;
        lhsused = 1;
      }else{
        for(i=0; i<rp->nrhs; i++){
          if( rp->rhsalias[i] && strcmp(cp,rp->rhsalias[i])==0 ){
            if( i==0 && dontUseRhs0 ){
              ErrorMsg(lemp->filename,rp->ruleline,
                 "Label %s used after '%s'.",
                 rp->rhsalias[0], zOvwrt);
              lemp->errorcnt++;
            }else if( cp!=rp->code && cp[-1]=='@' ){
              /* If the argument is of the form @X then substituted
              ** the token number of X, not the value of X */
              append_str("yymsp[%d].major",-1,i-rp->nrhs+1,0);
            }else{
              struct symbol *sp = rp->rhs[i];
              int dtnum;
              if( sp->type==MULTITERMINAL ){

Changes to tool/lempar.c.

633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
  if( yyRuleInfo[yyruleno].nrhs==0 ){
#ifdef YYTRACKMAXSTACKDEPTH
    if( yypParser->yyidx>yypParser->yyidxMax ){
      yypParser->yyidxMax = yypParser->yyidx;
    }
#endif
#if YYSTACKDEPTH>0 
    if( yypParser->yyidx>=YYSTACKDEPTH ){
      yyStackOverflow(yypParser);
      return;
    }
#else
    if( yypParser->yyidx>=yypParser->yystksz ){
      yyGrowStack(yypParser);
      if( yypParser->yyidx>=yypParser->yystksz ){
        yyStackOverflow(yypParser);
        return;
      }
    }
#endif
  }








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633
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645
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  if( yyRuleInfo[yyruleno].nrhs==0 ){
#ifdef YYTRACKMAXSTACKDEPTH
    if( yypParser->yyidx>yypParser->yyidxMax ){
      yypParser->yyidxMax = yypParser->yyidx;
    }
#endif
#if YYSTACKDEPTH>0 
    if( yypParser->yyidx>=YYSTACKDEPTH-1 ){
      yyStackOverflow(yypParser);
      return;
    }
#else
    if( yypParser->yyidx>=yypParser->yystksz-1 ){
      yyGrowStack(yypParser);
      if( yypParser->yyidx>=yypParser->yystksz-1 ){
        yyStackOverflow(yypParser);
        return;
      }
    }
#endif
  }