path: root/src/parse.y

/*
** 2001 September 15
**
** The author disclaims copyright to this source code.  In place of
** a legal notice, here is a blessing:
**
**    May you do good and not evil.
**    May you find forgiveness for yourself and forgive others.
**    May you share freely, never taking more than you give.
**
*************************************************************************
** This file contains SQLite's grammar for SQL.  Process this file
** using the lemon parser generator to generate C code that runs
** the parser.  Lemon will also generate a header file containing
** numeric codes for all of the tokens.
*/

// All token codes are small integers with #defines that begin with "TK_"
%token_prefix TK_

// The type of the data attached to each token is Token.  This is also the
// default type for non-terminals.
//
%token_type {Token}
%default_type {Token}

// The generated parser function takes a 4th argument as follows:
%extra_argument {Parse *pParse}

// This code runs whenever there is a syntax error
//
%syntax_error {
  UNUSED_PARAMETER(yymajor);  /* Silence some compiler warnings */
  assert( TOKEN.z[0] );  /* The tokenizer always gives us a token */
  sqlite3ErrorMsg(pParse, "near \"%T\": syntax error", &TOKEN);
}
%stack_overflow {
  UNUSED_PARAMETER(yypMinor); /* Silence some compiler warnings */
  sqlite3ErrorMsg(pParse, "parser stack overflow");
}

// The name of the generated procedure that implements the parser
// is as follows:
%name sqlite3Parser

// The following text is included near the beginning of the C source
// code file that implements the parser.
//
%include {
#include "sqliteInt.h"

/*
** Disable all error recovery processing in the parser push-down
** automaton.
*/
#define YYNOERRORRECOVERY 1

/*
** Make yytestcase() the same as testcase()
*/
#define yytestcase(X) testcase(X)

/*
** An instance of this structure holds information about the
** LIMIT clause of a SELECT statement.
*/
struct LimitVal {
  Expr *pLimit;    /* The LIMIT expression.  NULL if there is no limit */
  Expr *pOffset;   /* The OFFSET expression.  NULL if there is none */
};

/*
** An instance of this structure is used to store the LIKE,
** GLOB, NOT LIKE, and NOT GLOB operators.
*/
struct LikeOp {
  Token eOperator;  /* "like" or "glob" or "regexp" */
  int bNot;         /* True if the NOT keyword is present */
};

/*
** An instance of the following structure describes the event of a
** TRIGGER.  "a" is the event type, one of TK_UPDATE, TK_INSERT,
** TK_DELETE, or TK_INSTEAD.  If the event is of the form
**
**      UPDATE ON (a,b,c)
**
** Then the "b" IdList records the list "a,b,c".
*/
struct TrigEvent { int a; IdList * b; };

/*
** An instance of this structure holds the ATTACH key and the key type.
*/
struct AttachKey { int type;  Token key; };

/*
** One or more VALUES claues
*/
struct ValueList {
  ExprList *pList;
  Select *pSelect;
};

} // end %include

// Input is a single SQL command
input ::= cmdlist.
cmdlist ::= cmdlist ecmd.
cmdlist ::= ecmd.
ecmd ::= SEMI.
ecmd ::= explain cmdx SEMI.
explain ::= .           { sqlite3BeginParse(pParse, 0); }
%ifndef SQLITE_OMIT_EXPLAIN
explain ::= EXPLAIN.              { sqlite3BeginParse(pParse, 1); }
explain ::= EXPLAIN QUERY PLAN.   { sqlite3BeginParse(pParse, 2); }
%endif  SQLITE_OMIT_EXPLAIN
cmdx ::= cmd.           { sqlite3FinishCoding(pParse); }

///////////////////// Begin and end transactions. ////////////////////////////
//

cmd ::= BEGIN transtype(Y) trans_opt.  {sqlite3BeginTransaction(pParse, Y);}
trans_opt ::= .
trans_opt ::= TRANSACTION.
trans_opt ::= TRANSACTION nm.
%type transtype {int}
transtype(A) ::= .             {A = TK_DEFERRED;}
transtype(A) ::= DEFERRED(X).  {A = @X;}
transtype(A) ::= IMMEDIATE(X). {A = @X;}
transtype(A) ::= EXCLUSIVE(X). {A = @X;}
cmd ::= COMMIT trans_opt.      {sqlite3CommitTransaction(pParse);}
cmd ::= END trans_opt.         {sqlite3CommitTransaction(pParse);}
cmd ::= ROLLBACK trans_opt.    {sqlite3RollbackTransaction(pParse);}

savepoint_opt ::= SAVEPOINT.
savepoint_opt ::= .
cmd ::= SAVEPOINT nm(X). {
  sqlite3Savepoint(pParse, SAVEPOINT_BEGIN, &X);
}
cmd ::= RELEASE savepoint_opt nm(X). {
  sqlite3Savepoint(pParse, SAVEPOINT_RELEASE, &X);
}
cmd ::= ROLLBACK trans_opt TO savepoint_opt nm(X). {
  sqlite3Savepoint(pParse, SAVEPOINT_ROLLBACK, &X);
}

///////////////////// The CREATE TABLE statement ////////////////////////////
//
cmd ::= create_table create_table_args.
create_table ::= createkw temp(T) TABLE ifnotexists(E) nm(Y) dbnm(Z). {
   sqlite3StartTable(pParse,&Y,&Z,T,0,0,E);
}
createkw(A) ::= CREATE(X).  {
  pParse->db->lookaside.bEnabled = 0;
  A = X;
}
%type ifnotexists {int}
ifnotexists(A) ::= .              {A = 0;}
ifnotexists(A) ::= IF NOT EXISTS. {A = 1;}
%type temp {int}
%ifndef SQLITE_OMIT_TEMPDB
temp(A) ::= TEMP.  {A = 1;}
%endif  SQLITE_OMIT_TEMPDB
temp(A) ::= .      {A = 0;}
create_table_args ::= LP columnlist conslist_opt(X) RP(Y). {
  sqlite3EndTable(pParse,&X,&Y,0);
}
create_table_args ::= AS select(S). {
  sqlite3EndTable(pParse,0,0,S);
  sqlite3SelectDelete(pParse->db, S);
}
columnlist ::= columnlist COMMA column.
columnlist ::= column.

// A "column" is a complete description of a single column in a
// CREATE TABLE statement.  This includes the column name, its
// datatype, and other keywords such as PRIMARY KEY, UNIQUE, REFERENCES,
// NOT NULL and so forth.
//
column(A) ::= columnid(X) type carglist. {
  A.z = X.z;
  A.n = (int)(pParse->sLastToken.z-X.z) + pParse->sLastToken.n;
}
columnid(A) ::= nm(X). {
  sqlite3AddColumn(pParse,&X);
  A = X;
  pParse->constraintName.n = 0;
}


// An IDENTIFIER can be a generic identifier, or one of several
// keywords.  Any non-standard keyword can also be an identifier.
//
%type id {Token}
id(A) ::= ID(X).         {A = X;}
id(A) ::= INDEXED(X).    {A = X;}

// The following directive causes tokens ABORT, AFTER, ASC, etc. to
// fallback to ID if they will not parse as their original value.
// This obviates the need for the "id" nonterminal.
//
%fallback ID
  ABORT ACTION AFTER ANALYZE ASC ATTACH BEFORE BEGIN BY CASCADE CAST COLUMNKW
  CONFLICT DATABASE DEFERRED DESC DETACH EACH END EXCLUSIVE EXPLAIN FAIL FOR
  IGNORE IMMEDIATE INITIALLY INSTEAD LIKE_KW MATCH NO PLAN
  QUERY KEY OF OFFSET PRAGMA RAISE RELEASE REPLACE RESTRICT ROW ROLLBACK
  SAVEPOINT TEMP TRIGGER VACUUM VIEW VIRTUAL
%ifdef SQLITE_OMIT_COMPOUND_SELECT
  EXCEPT INTERSECT UNION
%endif SQLITE_OMIT_COMPOUND_SELECT
  REINDEX RENAME CTIME_KW IF
  .
%wildcard ANY.

// Define operator precedence early so that this is the first occurance
// of the operator tokens in the grammer.  Keeping the operators together
// causes them to be assigned integer values that are close together,
// which keeps parser tables smaller.
//
// The token values assigned to these symbols is determined by the order
// in which lemon first sees them.  It must be the case that ISNULL/NOTNULL,
// NE/EQ, GT/LE, and GE/LT are separated by only a single value.  See
// the sqlite3ExprIfFalse() routine for additional information on this
// constraint.
//
%left OR.
%left AND.
%right NOT.
%left IS MATCH LIKE_KW BETWEEN IN ISNULL NOTNULL NE EQ.
%left GT LE LT GE.
%right ESCAPE.
%left BITAND BITOR LSHIFT RSHIFT.
%left PLUS MINUS.
%left STAR SLASH REM.
%left CONCAT.
%left COLLATE.
%right BITNOT.

// And "ids" is an identifer-or-string.
//
%type ids {Token}
ids(A) ::= ID|STRING(X).   {A = X;}

// The name of a column or table can be any of the following:
//
%type nm {Token}
nm(A) ::= id(X).         {A = X;}
nm(A) ::= STRING(X).     {A = X;}
nm(A) ::= JOIN_KW(X).    {A = X;}

// A typetoken is really one or more tokens that form a type name such
// as can be found after the column name in a CREATE TABLE statement.
// Multiple tokens are concatenated to form the value of the typetoken.
//
%type typetoken {Token}
type ::= .
type ::= typetoken(X).                   {sqlite3AddColumnType(pParse,&X);}
typetoken(A) ::= typename(X).   {A = X;}
typetoken(A) ::= typename(X) LP signed RP(Y). {
  A.z = X.z;
  A.n = (int)(&Y.z[Y.n] - X.z);
}
typetoken(A) ::= typename(X) LP signed COMMA signed RP(Y). {
  A.z = X.z;
  A.n = (int)(&Y.z[Y.n] - X.z);
}
%type typename {Token}
typename(A) ::= ids(X).             {A = X;}
typename(A) ::= typename(X) ids(Y). {A.z=X.z; A.n=Y.n+(int)(Y.z-X.z);}
signed ::= plus_num.
signed ::= minus_num.

// "carglist" is a list of additional constraints that come after the
// column name and column type in a CREATE TABLE statement.
//
carglist ::= carglist ccons.
carglist ::= .
ccons ::= CONSTRAINT nm(X).           {pParse->constraintName = X;}
ccons ::= DEFAULT term(X).            {sqlite3AddDefaultValue(pParse,&X);}
ccons ::= DEFAULT LP expr(X) RP.      {sqlite3AddDefaultValue(pParse,&X);}
ccons ::= DEFAULT PLUS term(X).       {sqlite3AddDefaultValue(pParse,&X);}
ccons ::= DEFAULT MINUS(A) term(X).      {
  ExprSpan v;
  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.
ccons ::= NOT NULL onconf(R).    {sqlite3AddNotNull(pParse, R);}
ccons ::= PRIMARY KEY sortorder(Z) onconf(R) autoinc(I).
                                 {sqlite3AddPrimaryKey(pParse,0,R,I,Z);}
ccons ::= UNIQUE onconf(R).      {sqlite3CreateIndex(pParse,0,0,0,0,R,0,0,0,0);}
ccons ::= CHECK LP expr(X) RP.   {sqlite3AddCheckConstraint(pParse,X.pExpr);}
ccons ::= REFERENCES nm(T) idxlist_opt(TA) refargs(R).
                                 {sqlite3CreateForeignKey(pParse,0,&T,TA,R);}
ccons ::= defer_subclause(D).    {sqlite3DeferForeignKey(pParse,D);}
ccons ::= COLLATE ids(C).        {sqlite3AddCollateType(pParse, &C);}

// The optional AUTOINCREMENT keyword
%type autoinc {int}
autoinc(X) ::= .          {X = 0;}
autoinc(X) ::= AUTOINCR.  {X = 1;}

// The next group of rules parses the arguments to a REFERENCES clause
// that determine if the referential integrity checking is deferred or
// or immediate and which determine what action to take if a ref-integ
// check fails.
//
%type refargs {int}
refargs(A) ::= .                  { A = OE_None*0x0101; /* EV: R-19803-45884 */}
refargs(A) ::= refargs(X) refarg(Y). { A = (X & ~Y.mask) | Y.value; }
%type refarg {struct {int value; int mask;}}
refarg(A) ::= MATCH nm.              { A.value = 0;     A.mask = 0x000000; }
refarg(A) ::= ON INSERT refact.      { A.value = 0;     A.mask = 0x000000; }
refarg(A) ::= ON DELETE refact(X).   { A.value = X;     A.mask = 0x0000ff; }
refarg(A) ::= ON UPDATE refact(X).   { A.value = X<<8;  A.mask = 0x00ff00; }
%type refact {int}
refact(A) ::= SET NULL.              { A = OE_SetNull;  /* EV: R-33326-45252 */}
refact(A) ::= SET DEFAULT.           { A = OE_SetDflt;  /* EV: R-33326-45252 */}
refact(A) ::= CASCADE.               { A = OE_Cascade;  /* EV: R-33326-45252 */}
refact(A) ::= RESTRICT.              { A = OE_Restrict; /* EV: R-33326-45252 */}
refact(A) ::= NO ACTION.             { A = OE_None;     /* EV: R-33326-45252 */}
%type defer_subclause {int}
defer_subclause(A) ::= NOT DEFERRABLE init_deferred_pred_opt.     {A = 0;}
defer_subclause(A) ::= DEFERRABLE init_deferred_pred_opt(X).      {A = X;}
%type init_deferred_pred_opt {int}
init_deferred_pred_opt(A) ::= .                       {A = 0;}
init_deferred_pred_opt(A) ::= INITIALLY DEFERRED.     {A = 1;}
init_deferred_pred_opt(A) ::= INITIALLY IMMEDIATE.    {A = 0;}

conslist_opt(A) ::= .                         {A.n = 0; A.z = 0;}
conslist_opt(A) ::= COMMA(X) conslist.        {A = X;}
conslist ::= conslist tconscomma tcons.
conslist ::= tcons.
tconscomma ::= COMMA.            {pParse->constraintName.n = 0;}
tconscomma ::= .
tcons ::= CONSTRAINT nm(X).      {pParse->constraintName = X;}
tcons ::= PRIMARY KEY LP idxlist(X) autoinc(I) RP onconf(R).
                                 {sqlite3AddPrimaryKey(pParse,X,R,I,0);}
tcons ::= UNIQUE LP idxlist(X) RP onconf(R).
                                 {sqlite3CreateIndex(pParse,0,0,0,X,R,0,0,0,0);}
tcons ::= CHECK LP expr(E) RP onconf.
                                 {sqlite3AddCheckConstraint(pParse,E.pExpr);}
tcons ::= FOREIGN KEY LP idxlist(FA) RP
          REFERENCES nm(T) idxlist_opt(TA) refargs(R) defer_subclause_opt(D). {
    sqlite3CreateForeignKey(pParse, FA, &T, TA, R);
    sqlite3DeferForeignKey(pParse, D);
}
%type defer_subclause_opt {int}
defer_subclause_opt(A) ::= .                    {A = 0;}
defer_subclause_opt(A) ::= defer_subclause(X).  {A = X;}

// The following is a non-standard extension that allows us to declare the
// default behavior when there is a constraint conflict.
//
%type onconf {int}
%type orconf {u8}
%type resolvetype {int}
onconf(A) ::= .                              {A = OE_Default;}
onconf(A) ::= ON CONFLICT resolvetype(X).    {A = X;}
orconf(A) ::= .                              {A = OE_Default;}
orconf(A) ::= OR resolvetype(X).             {A = (u8)X;}
resolvetype(A) ::= raisetype(X).             {A = X;}
resolvetype(A) ::= IGNORE.                   {A = OE_Ignore;}
resolvetype(A) ::= REPLACE.                  {A = OE_Replace;}

////////////////////////// The DROP TABLE /////////////////////////////////////
//
cmd ::= DROP TABLE ifexists(E) fullname(X). {
  sqlite3DropTable(pParse, X, 0, E);
}
%type ifexists {int}
ifexists(A) ::= IF EXISTS.   {A = 1;}
ifexists(A) ::= .            {A = 0;}

///////////////////// The CREATE VIEW statement /////////////////////////////
//
%ifndef SQLITE_OMIT_VIEW
cmd ::= createkw(X) temp(T) VIEW ifnotexists(E) nm(Y) dbnm(Z) AS select(S). {
  sqlite3CreateView(pParse, &X, &Y, &Z, S, T, E);
}
cmd ::= DROP VIEW ifexists(E) fullname(X). {
  sqlite3DropTable(pParse, X, 1, E);
}
%endif  SQLITE_OMIT_VIEW

//////////////////////// The SELECT statement /////////////////////////////////
//
cmd ::= select(X).  {
  SelectDest dest = {SRT_Output, 0, 0, 0, 0};
  sqlite3Select(pParse, X, &dest);
  sqlite3ExplainBegin(pParse->pVdbe);
  sqlite3ExplainSelect(pParse->pVdbe, X);
  sqlite3ExplainFinish(pParse->pVdbe);
  sqlite3SelectDelete(pParse->db, X);
}

%type select {Select*}
%destructor select {sqlite3SelectDelete(pParse->db, $$);}
%type oneselect {Select*}
%destructor oneselect {sqlite3SelectDelete(pParse->db, $$);}

select(A) ::= oneselect(X).                      {A = X;}
%ifndef SQLITE_OMIT_COMPOUND_SELECT
select(A) ::= select(X) multiselect_op(Y) oneselect(Z).  {
  if( Z ){
    Z->op = (u8)Y;
    Z->pPrior = X;
  }else{
    sqlite3SelectDelete(pParse->db, X);
  }
  A = Z;
}
%type multiselect_op {int}
multiselect_op(A) ::= UNION(OP).             {A = @OP;}
multiselect_op(A) ::= UNION ALL.             {A = TK_ALL;}
multiselect_op(A) ::= EXCEPT|INTERSECT(OP).  {A = @OP;}
%endif SQLITE_OMIT_COMPOUND_SELECT
oneselect(A) ::= SELECT 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);
}

// The "distinct" nonterminal is true (1) if the DISTINCT keyword is
// present and false (0) if it is not.
//
%type distinct {int}
distinct(A) ::= DISTINCT.   {A = 1;}
distinct(A) ::= ALL.        {A = 0;}
distinct(A) ::= .           {A = 0;}

// selcollist is a list of expressions that are to become the return
// values of the SELECT statement.  The "*" in statements like
// "SELECT * FROM ..." is encoded as a special expression with an
// opcode of TK_ALL.
//
%type selcollist {ExprList*}
%destructor selcollist {sqlite3ExprListDelete(pParse->db, $$);}
%type sclp {ExprList*}
%destructor sclp {sqlite3ExprListDelete(pParse->db, $$);}
sclp(A) ::= selcollist(X) COMMA.             {A = X;}
sclp(A) ::= .                                {A = 0;}
selcollist(A) ::= sclp(P) expr(X) as(Y).     {
   A = sqlite3ExprListAppend(pParse, P, X.pExpr);
   if( Y.n>0 ) sqlite3ExprListSetName(pParse, A, &Y, 1);
   sqlite3ExprListSetSpan(pParse,A,&X);
}
selcollist(A) ::= sclp(P) STAR. {
  Expr *p = sqlite3Expr(pParse->db, TK_ALL, 0);
  A = sqlite3ExprListAppend(pParse, P, p);
}
selcollist(A) ::= sclp(P) nm(X) DOT STAR(Y). {
  Expr *pRight = sqlite3PExpr(pParse, TK_ALL, 0, 0, &Y);
  Expr *pLeft = sqlite3PExpr(pParse, TK_ID, 0, 0, &X);
  Expr *pDot = sqlite3PExpr(pParse, TK_DOT, pLeft, pRight, 0);
  A = sqlite3ExprListAppend(pParse,P, pDot);
}

// An option "AS <id>" phrase that can follow one of the expressions that
// define the result set, or one of the tables in the FROM clause.
//
%type as {Token}
as(X) ::= AS nm(Y).    {X = Y;}
as(X) ::= ids(Y).      {X = Y;}
as(X) ::= .            {X.n = 0;}


%type seltablist {SrcList*}
%destructor seltablist {sqlite3SrcListDelete(pParse->db, $$);}
%type stl_prefix {SrcList*}
%destructor stl_prefix {sqlite3SrcListDelete(pParse->db, $$);}
%type from {SrcList*}
%destructor from {sqlite3SrcListDelete(pParse->db, $$);}

// A complete FROM clause.
//
from(A) ::= .                {A = sqlite3DbMallocZero(pParse->db, sizeof(*A));}
from(A) ::= FROM seltablist(X). {
  A = X;
  sqlite3SrcListShiftJoinType(A);
}

// "seltablist" is a "Select Table List" - the content of the FROM clause
// in a SELECT statement.  "stl_prefix" is a prefix of this list.
//
stl_prefix(A) ::= seltablist(X) joinop(Y).    {
   A = X;
   if( ALWAYS(A && A->nSrc>0) ) A->a[A->nSrc-1].jointype = (u8)Y;
}
stl_prefix(A) ::= .                           {A = 0;}
seltablist(A) ::= stl_prefix(X) nm(Y) dbnm(D) as(Z) indexed_opt(I) on_opt(N) using_opt(U). {
  A = sqlite3SrcListAppendFromTerm(pParse,X,&Y,&D,&Z,0,N,U);
  sqlite3SrcListIndexedBy(pParse, A, &I);
}
%ifndef SQLITE_OMIT_SUBQUERY
  seltablist(A) ::= stl_prefix(X) LP select(S) RP
                    as(Z) on_opt(N) using_opt(U). {
    A = sqlite3SrcListAppendFromTerm(pParse,X,0,0,&Z,S,N,U);
  }
  seltablist(A) ::= stl_prefix(X) LP seltablist(F) RP
                    as(Z) on_opt(N) using_opt(U). {
    if( X==0 && Z.n==0 && N==0 && U==0 ){
      A = F;
    }else{
      Select *pSubquery;
      sqlite3SrcListShiftJoinType(F);
      pSubquery = sqlite3SelectNew(pParse,0,F,0,0,0,0,0,0,0);
      A = sqlite3SrcListAppendFromTerm(pParse,X,0,0,&Z,pSubquery,N,U);
    }
  }
  
  // A seltablist_paren nonterminal represents anything in a FROM that
  // is contained inside parentheses.  This can be either a subquery or
  // a grouping of table and subqueries.
  //
//  %type seltablist_paren {Select*}
//  %destructor seltablist_paren {sqlite3SelectDelete(pParse->db, $$);}
//  seltablist_paren(A) ::= select(S).      {A = S;}
//  seltablist_paren(A) ::= seltablist(F).  {
//     sqlite3SrcListShiftJoinType(F);
//     A = sqlite3SelectNew(pParse,0,F,0,0,0,0,0,0,0);
//  }
%endif  SQLITE_OMIT_SUBQUERY

%type dbnm {Token}
dbnm(A) ::= .          {A.z=0; A.n=0;}
dbnm(A) ::= DOT nm(X). {A = X;}

%type fullname {SrcList*}
%destructor fullname {sqlite3SrcListDelete(pParse->db, $$);}
fullname(A) ::= nm(X) dbnm(Y).  {A = sqlite3SrcListAppend(pParse->db,0,&X,&Y);}

%type joinop {int}
%type joinop2 {int}
joinop(X) ::= COMMA|JOIN.              { X = JT_INNER; }
joinop(X) ::= JOIN_KW(A) JOIN.         { X = sqlite3JoinType(pParse,&A,0,0); }
joinop(X) ::= JOIN_KW(A) nm(B) JOIN.   { X = sqlite3JoinType(pParse,&A,&B,0); }
joinop(X) ::= JOIN_KW(A) nm(B) nm(C) JOIN.
                                       { X = sqlite3JoinType(pParse,&A,&B,&C); }

%type on_opt {Expr*}
%destructor on_opt {sqlite3ExprDelete(pParse->db, $$);}
on_opt(N) ::= ON expr(E).   {N = E.pExpr;}
on_opt(N) ::= .             {N = 0;}

// Note that this block abuses the Token type just a little. If there is
// no "INDEXED BY" clause, the returned token is empty (z==0 && n==0). If
// there is an INDEXED BY clause, then the token is populated as per normal,
// with z pointing to the token data and n containing the number of bytes
// in the token.
//
// If there is a "NOT INDEXED" clause, then (z==0 && n==1), which is 
// normally illegal. The sqlite3SrcListIndexedBy() function 
// recognizes and interprets this as a special case.
//
%type indexed_opt {Token}
indexed_opt(A) ::= .                 {A.z=0; A.n=0;}
indexed_opt(A) ::= INDEXED BY nm(X). {A = X;}
indexed_opt(A) ::= NOT INDEXED.      {A.z=0; A.n=1;}

%type using_opt {IdList*}
%destructor using_opt {sqlite3IdListDelete(pParse->db, $$);}
using_opt(U) ::= USING LP inscollist(L) RP.  {U = L;}
using_opt(U) ::= .                        {U = 0;}


%type orderby_opt {ExprList*}
%destructor orderby_opt {sqlite3ExprListDelete(pParse->db, $$);}
%type sortlist {ExprList*}
%destructor sortlist {sqlite3ExprListDelete(pParse->db, $$);}

orderby_opt(A) ::= .                          {A = 0;}
orderby_opt(A) ::= ORDER BY sortlist(X).      {A = X;}
sortlist(A) ::= sortlist(X) COMMA expr(Y) sortorder(Z). {
  A = sqlite3ExprListAppend(pParse,X,Y.pExpr);
  if( A ) A->a[A->nExpr-1].sortOrder = (u8)Z;
}
sortlist(A) ::= expr(Y) sortorder(Z). {
  A = sqlite3ExprListAppend(pParse,0,Y.pExpr);
  if( A && ALWAYS(A->a) ) A->a[0].sortOrder = (u8)Z;
}

%type sortorder {int}

sortorder(A) ::= ASC.           {A = SQLITE_SO_ASC;}
sortorder(A) ::= DESC.          {A = SQLITE_SO_DESC;}
sortorder(A) ::= .              {A = SQLITE_SO_ASC;}

%type groupby_opt {ExprList*}
%destructor groupby_opt {sqlite3ExprListDelete(pParse->db, $$);}
groupby_opt(A) ::= .                      {A = 0;}
groupby_opt(A) ::= GROUP BY nexprlist(X). {A = X;}

%type having_opt {Expr*}
%destructor having_opt {sqlite3ExprDelete(pParse->db, $$);}
having_opt(A) ::= .                {A = 0;}
having_opt(A) ::= HAVING expr(X).  {A = X.pExpr;}

%type limit_opt {struct LimitVal}

// The destructor for limit_opt will never fire in the current grammar.
// The limit_opt non-terminal only occurs at the end of a single production
// rule for SELECT statements.  As soon as the rule that create the 
// limit_opt non-terminal reduces, the SELECT statement rule will also
// reduce.  So there is never a limit_opt non-terminal on the stack 
// except as a transient.  So there is never anything to destroy.
//
//%destructor limit_opt {
//  sqlite3ExprDelete(pParse->db, $$.pLimit);
//  sqlite3ExprDelete(pParse->db, $$.pOffset);
//}
limit_opt(A) ::= .                    {A.pLimit = 0; A.pOffset = 0;}
limit_opt(A) ::= LIMIT expr(X).       {A.pLimit = X.pExpr; A.pOffset = 0;}
limit_opt(A) ::= LIMIT expr(X) OFFSET expr(Y). 
                                      {A.pLimit = X.pExpr; A.pOffset = Y.pExpr;}
limit_opt(A) ::= LIMIT expr(X) COMMA expr(Y). 
                                      {A.pOffset = X.pExpr; A.pLimit = Y.pExpr;}

/////////////////////////// The DELETE statement /////////////////////////////
//
%ifdef SQLITE_ENABLE_UPDATE_DELETE_LIMIT
cmd ::= DELETE FROM fullname(X) indexed_opt(I) where_opt(W) 
        orderby_opt(O) limit_opt(L). {
  sqlite3SrcListIndexedBy(pParse, X, &I);
  W = sqlite3LimitWhere(pParse, X, W, O, L.pLimit, L.pOffset, "DELETE");
  sqlite3DeleteFrom(pParse,X,W);
}
%endif
%ifndef SQLITE_ENABLE_UPDATE_DELETE_LIMIT
cmd ::= DELETE FROM fullname(X) indexed_opt(I) where_opt(W). {
  sqlite3SrcListIndexedBy(pParse, X, &I);
  sqlite3DeleteFrom(pParse,X,W);
}
%endif

%type where_opt {Expr*}
%destructor where_opt {sqlite3ExprDelete(pParse->db, $$);}

where_opt(A) ::= .                    {A = 0;}
where_opt(A) ::= WHERE expr(X).       {A = X.pExpr;}

////////////////////////// The UPDATE command ////////////////////////////////
//
%ifdef SQLITE_ENABLE_UPDATE_DELETE_LIMIT
cmd ::= UPDATE orconf(R) fullname(X) indexed_opt(I) SET setlist(Y) where_opt(W) orderby_opt(O) limit_opt(L).  {
  sqlite3SrcListIndexedBy(pParse, X, &I);
  sqlite3ExprListCheckLength(pParse,Y,"set list"); 
  W = sqlite3LimitWhere(pParse, X, W, O, L.pLimit, L.pOffset, "UPDATE");
  sqlite3Update(pParse,X,Y,W,R);
}
%endif
%ifndef SQLITE_ENABLE_UPDATE_DELETE_LIMIT
cmd ::= UPDATE orconf(R) fullname(X) indexed_opt(I) SET setlist(Y) where_opt(W).  {
  sqlite3SrcListIndexedBy(pParse, X, &I);
  sqlite3ExprListCheckLength(pParse,Y,"set list"); 
  sqlite3Update(pParse,X,Y,W,R);
}
%endif

%type setlist {ExprList*}
%destructor setlist {sqlite3ExprListDelete(pParse->db, $$);}

setlist(A) ::= setlist(Z) COMMA nm(X) EQ expr(Y). {
  A = sqlite3ExprListAppend(pParse, Z, Y.pExpr);
  sqlite3ExprListSetName(pParse, A, &X, 1);
}
setlist(A) ::= nm(X) EQ expr(Y). {
  A = sqlite3ExprListAppend(pParse, 0, Y.pExpr);
  sqlite3ExprListSetName(pParse, A, &X, 1);
}

////////////////////////// The INSERT command /////////////////////////////////
//
cmd ::= insert_cmd(R) INTO fullname(X) inscollist_opt(F) valuelist(Y).
            {sqlite3Insert(pParse, X, Y.pList, Y.pSelect, F, R);}
cmd ::= insert_cmd(R) INTO fullname(X) inscollist_opt(F) select(S).
            {sqlite3Insert(pParse, X, 0, S, F, R);}
cmd ::= insert_cmd(R) INTO fullname(X) inscollist_opt(F) DEFAULT VALUES.
            {sqlite3Insert(pParse, X, 0, 0, F, R);}

%type insert_cmd {u8}
insert_cmd(A) ::= INSERT orconf(R).   {A = R;}
insert_cmd(A) ::= REPLACE.            {A = OE_Replace;}

// A ValueList is either a single VALUES clause or a comma-separated list
// of VALUES clauses.  If it is a single VALUES clause then the
// ValueList.pList field points to the expression list of that clause.
// If it is a list of VALUES clauses, then those clauses are transformed
// into a set of SELECT statements without FROM clauses and connected by
// UNION ALL and the ValueList.pSelect points to the right-most SELECT in
// that compound.
%type valuelist {struct ValueList}
%destructor valuelist {
  sqlite3ExprListDelete(pParse->db, $$.pList);
  sqlite3SelectDelete(pParse->db, $$.pSelect);
}
valuelist(A) ::= VALUES LP nexprlist(X) RP. {
  A.pList = X;
  A.pSelect = 0;
}

// Since a list of VALUEs is inplemented as a compound SELECT, we have
// to disable the value list option if compound SELECTs are disabled.
%ifndef SQLITE_OMIT_COMPOUND_SELECT
valuelist(A) ::= valuelist(X) COMMA LP exprlist(Y) RP. {
  Select *pRight = sqlite3SelectNew(pParse, Y, 0, 0, 0, 0, 0, 0, 0, 0);
  if( X.pList ){
    X.pSelect = sqlite3SelectNew(pParse, X.pList, 0, 0, 0, 0, 0, 0, 0, 0);
    X.pList = 0;
  }
  A.pList = 0;
  if( X.pSelect==0 || pRight==0 ){
    sqlite3SelectDelete(pParse->db, pRight);
    sqlite3SelectDelete(pParse->db, X.pSelect);
    A.pSelect = 0;
  }else{
    pRight->op = TK_ALL;
    pRight->pPrior = X.pSelect;
    pRight->selFlags |= SF_Values;
    pRight->pPrior->selFlags |= SF_Values;
    A.pSelect = pRight;
  }
}
%endif SQLITE_OMIT_COMPOUND_SELECT

%type inscollist_opt {IdList*}
%destructor inscollist_opt {sqlite3IdListDelete(pParse->db, $$);}
%type inscollist {IdList*}
%destructor inscollist {sqlite3IdListDelete(pParse->db, $$);}

inscollist_opt(A) ::= .                       {A = 0;}
inscollist_opt(A) ::= LP inscollist(X) RP.    {A = X;}
inscollist(A) ::= inscollist(X) COMMA nm(Y).
    {A = sqlite3IdListAppend(pParse->db,X,&Y);}
inscollist(A) ::= nm(Y).
    {A = sqlite3IdListAppend(pParse->db,0,&Y);}

/////////////////////////// Expression Processing /////////////////////////////
//

%type expr {ExprSpan}
%destructor expr {sqlite3ExprDelete(pParse->db, $$.pExpr);}
%type term {ExprSpan}
%destructor term {sqlite3ExprDelete(pParse->db, $$.pExpr);}

%include {
  /* This is a utility routine used to set the ExprSpan.zStart and
  ** ExprSpan.zEnd values of pOut so that the span covers the complete
  ** range of text beginning with pStart and going to the end of pEnd.
  */
  static void spanSet(ExprSpan *pOut, Token *pStart, Token *pEnd){
    pOut->zStart = pStart->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(X).             {A = X;}
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);
  A.pExpr = sqlite3PExpr(pParse, TK_DOT, temp1, temp2, 0);
  spanSet(&A,&X,&Y);
}
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);
  A.pExpr = sqlite3PExpr(pParse, TK_DOT, temp1, temp4, 0);
  spanSet(&A,&X,&Z);
}
term(A) ::= INTEGER|FLOAT|BLOB(X).  {spanExpr(&A, pParse, @X, &X);}
term(A) ::= STRING(X).              {spanExpr(&A, pParse, @X, &X);}
expr(A) ::= REGISTER(X).     {
  /* 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);
  }
  spanSet(&A, &X, &X);
}
expr(A) ::= VARIABLE(X).     {
  spanExpr(&A, pParse, TK_VARIABLE, &X);
  sqlite3ExprAssignVarNumber(pParse, A.pExpr);
  spanSet(&A, &X, &X);
}
expr(A) ::= expr(E) COLLATE ids(C). {
  A.pExpr = sqlite3ExprSetCollByToken(pParse, E.pExpr, &C);
  A.zStart = E.zStart;
  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);
  spanSet(&A,&X,&E);
  if( D && A.pExpr ){
    A.pExpr->flags |= EP_Distinct;
  }
}
expr(A) ::= ID(X) LP STAR RP(E). {
  A.pExpr = sqlite3ExprFunction(pParse, 0, &X);
  spanSet(&A,&X,&E);
}
term(A) ::= CTIME_KW(OP). {
  /* The CURRENT_TIME, CURRENT_DATE, and CURRENT_TIMESTAMP values are
  ** treated as functions that return constants */
  A.pExpr = sqlite3ExprFunction(pParse, 0,&OP);
  if( A.pExpr ){
    A.pExpr->op = TK_CONST_FUNC;  
  }
  spanSet(&A, &OP, &OP);
}

%include {
  /* This routine constructs a binary expression node out of two ExprSpan
  ** objects and uses the result to populate a new ExprSpan object.
  */
  static void spanBinaryExpr(
    ExprSpan *pOut,     /* Write the result here */
    Parse *pParse,      /* The parsing context.  Errors accumulate here */
    int op,             /* The binary operation */
    ExprSpan *pLeft,    /* The left operand */
    ExprSpan *pRight    /* The right operand */
  ){
    pOut->pExpr = sqlite3PExpr(pParse, op, pLeft->pExpr, pRight->pExpr, 0);
    pOut->zStart = pLeft->zStart;
    pOut->zEnd = pRight->zEnd;
  }
}

expr(A) ::= expr(X) AND(OP) expr(Y).    {spanBinaryExpr(&A,pParse,@OP,&X,&Y);}
expr(A) ::= expr(X) OR(OP) expr(Y).     {spanBinaryExpr(&A,pParse,@OP,&X,&Y);}
expr(A) ::= expr(X) LT|GT|GE|LE(OP) expr(Y).
                                        {spanBinaryExpr(&A,pParse,@OP,&X,&Y);}
expr(A) ::= expr(X) EQ|NE(OP) expr(Y).  {spanBinaryExpr(&A,pParse,@OP,&X,&Y);}
expr(A) ::= expr(X) BITAND|BITOR|LSHIFT|RSHIFT(OP) expr(Y).
                                        {spanBinaryExpr(&A,pParse,@OP,&X,&Y);}
expr(A) ::= expr(X) PLUS|MINUS(OP) expr(Y).
                                        {spanBinaryExpr(&A,pParse,@OP,&X,&Y);}
expr(A) ::= expr(X) STAR|SLASH|REM(OP) expr(Y).
                                        {spanBinaryExpr(&A,pParse,@OP,&X,&Y);}
expr(A) ::= expr(X) CONCAT(OP) expr(Y). {spanBinaryExpr(&A,pParse,@OP,&X,&Y);}
%type likeop {struct LikeOp}
likeop(A) ::= LIKE_KW(X).     {A.eOperator = X; A.bNot = 0;}
likeop(A) ::= NOT LIKE_KW(X). {A.eOperator = X; A.bNot = 1;}
likeop(A) ::= MATCH(X).       {A.eOperator = X; A.bNot = 0;}
likeop(A) ::= NOT MATCH(X).   {A.eOperator = X; A.bNot = 1;}
expr(A) ::= expr(X) likeop(OP) expr(Y).  [LIKE_KW]  {
  ExprList *pList;
  pList = sqlite3ExprListAppend(pParse,0, Y.pExpr);
  pList = sqlite3ExprListAppend(pParse,pList, X.pExpr);
  A.pExpr = sqlite3ExprFunction(pParse, pList, &OP.eOperator);
  if( OP.bNot ) A.pExpr = sqlite3PExpr(pParse, TK_NOT, A.pExpr, 0, 0);
  A.zStart = X.zStart;
  A.zEnd = Y.zEnd;
  if( A.pExpr ) A.pExpr->flags |= EP_InfixFunc;
}
expr(A) ::= expr(X) likeop(OP) expr(Y) ESCAPE expr(E).  [LIKE_KW]  {
  ExprList *pList;
  pList = sqlite3ExprListAppend(pParse,0, Y.pExpr);
  pList = sqlite3ExprListAppend(pParse,pList, X.pExpr);
  pList = sqlite3ExprListAppend(pParse,pList, E.pExpr);
  A.pExpr = sqlite3ExprFunction(pParse, pList, &OP.eOperator);
  if( OP.bNot ) A.pExpr = sqlite3PExpr(pParse, TK_NOT, A.pExpr, 0, 0);
  A.zStart = X.zStart;
  A.zEnd = E.zEnd;
  if( A.pExpr ) A.pExpr->flags |= EP_InfixFunc;
}

%include {
  /* Construct an expression node for a unary postfix operator
  */
  static void spanUnaryPostfix(
    ExprSpan *pOut,        /* Write the new expression node here */
    Parse *pParse,         /* Parsing context to record errors */
    int op,                /* The operator */
    ExprSpan *pOperand,    /* The operand */
    Token *pPostOp         /* The operand token for setting the span */
  ){
    pOut->pExpr = sqlite3PExpr(pParse, op, pOperand->pExpr, 0, 0);
    pOut->zStart = pOperand->zStart;
    pOut->zEnd = &pPostOp->z[pPostOp->n];
  }                           
}

expr(A) ::= expr(X) ISNULL|NOTNULL(E).   {spanUnaryPostfix(&A,pParse,@E,&X,&E);}
expr(A) ::= expr(X) NOT NULL(E). {spanUnaryPostfix(&A,pParse,TK_NOTNULL,&X,&E);}

%include {
  /* A routine to convert a binary TK_IS or TK_ISNOT expression into a
  ** unary TK_ISNULL or TK_NOTNULL expression. */
  static void binaryToUnaryIfNull(Parse *pParse, Expr *pY, Expr *pA, int op){
    sqlite3 *db = pParse->db;
    if( db->mallocFailed==0 && pY->op==TK_NULL ){
      pA->op = (u8)op;
      sqlite3ExprDelete(db, pA->pRight);
      pA->pRight = 0;
    }
  }
}

//    expr1 IS expr2
//    expr1 IS NOT expr2
//
// If expr2 is NULL then code as TK_ISNULL or TK_NOTNULL.  If expr2
// is any other expression, code as TK_IS or TK_ISNOT.
// 
expr(A) ::= expr(X) IS expr(Y).     {
  spanBinaryExpr(&A,pParse,TK_IS,&X,&Y);
  binaryToUnaryIfNull(pParse, Y.pExpr, A.pExpr, TK_ISNULL);
}
expr(A) ::= expr(X) IS NOT expr(Y). {
  spanBinaryExpr(&A,pParse,TK_ISNOT,&X,&Y);
  binaryToUnaryIfNull(pParse, Y.pExpr, A.pExpr, TK_NOTNULL);
}

%include {
  /* Construct an expression node for a unary prefix operator
  */
  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(W) between_op(N) expr(X) AND expr(Y). [BETWEEN] {
  ExprList *pList = sqlite3ExprListAppend(pParse,0, X.pExpr);
  pList = sqlite3ExprListAppend(pParse,pList, Y.pExpr);
  A.pExpr = sqlite3PExpr(pParse, TK_BETWEEN, W.pExpr, 0, 0);
  if( A.pExpr ){
    A.pExpr->x.pList = pList;
  }else{
    sqlite3ExprListDelete(pParse->db, pList);
  } 
  if( N ) A.pExpr = sqlite3PExpr(pParse, TK_NOT, A.pExpr, 0, 0);
  A.zStart = W.zStart;
  A.zEnd = Y.zEnd;
}
%ifndef SQLITE_OMIT_SUBQUERY
  %type in_op {int}
  in_op(A) ::= IN.      {A = 0;}
  in_op(A) ::= NOT IN.  {A = 1;}
  expr(A) ::= expr(X) in_op(N) LP exprlist(Y) RP(E). [IN] {
    if( Y==0 ){
      /* Expressions of the form
      **
      **      expr1 IN ()
      **      expr1 NOT IN ()
      **
      ** simplify to constants 0 (false) and 1 (true), respectively,
      ** regardless of the value of expr1.
      */
      A.pExpr = sqlite3PExpr(pParse, TK_INTEGER, 0, 0, &sqlite3IntTokens[N]);
      sqlite3ExprDelete(pParse->db, X.pExpr);
    }else{
      A.pExpr = sqlite3PExpr(pParse, TK_IN, X.pExpr, 0, 0);
      if( A.pExpr ){
        A.pExpr->x.pList = Y;
        sqlite3ExprSetHeight(pParse, A.pExpr);
      }else{
        sqlite3ExprListDelete(pParse->db, Y);
      }
      if( N ) A.pExpr = sqlite3PExpr(pParse, TK_NOT, A.pExpr, 0, 0);
    }
    A.zStart = X.zStart;
    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);
      sqlite3ExprSetHeight(pParse, A.pExpr);
    }else{
      sqlite3SelectDelete(pParse->db, X);
    }
    A.zStart = B.z;
    A.zEnd = &E.z[E.n];
  }
  expr(A) ::= expr(X) in_op(N) LP select(Y) RP(E).  [IN] {
    A.pExpr = sqlite3PExpr(pParse, TK_IN, X.pExpr, 0, 0);
    if( A.pExpr ){
      A.pExpr->x.pSelect = Y;
      ExprSetProperty(A.pExpr, EP_xIsSelect);
      sqlite3ExprSetHeight(pParse, A.pExpr);
    }else{
      sqlite3SelectDelete(pParse->db, Y);
    }
    if( N ) A.pExpr = sqlite3PExpr(pParse, TK_NOT, A.pExpr, 0, 0);
    A.zStart = X.zStart;
    A.zEnd = &E.z[E.n];
  }
  expr(A) ::= expr(X) in_op(N) nm(Y) dbnm(Z). [IN] {
    SrcList *pSrc = sqlite3SrcListAppend(pParse->db, 0,&Y,&Z);
    A.pExpr = sqlite3PExpr(pParse, TK_IN, X.pExpr, 0, 0);
    if( A.pExpr ){
      A.pExpr->x.pSelect = sqlite3SelectNew(pParse, 0,pSrc,0,0,0,0,0,0,0);
      ExprSetProperty(A.pExpr, EP_xIsSelect);
      sqlite3ExprSetHeight(pParse, A.pExpr);
    }else{
      sqlite3SrcListDelete(pParse->db, pSrc);
    }
    if( N ) A.pExpr = sqlite3PExpr(pParse, TK_NOT, A.pExpr, 0, 0);
    A.zStart = X.zStart;
    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);
      sqlite3ExprSetHeight(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, Z, 0);
  if( A.pExpr ){
    A.pExpr->x.pList = Y;
    sqlite3ExprSetHeight(pParse, A.pExpr);
  }else{
    sqlite3ExprListDelete(pParse->db, Y);
  }
  A.zStart = C.z;
  A.zEnd = &E.z[E.n];
}
%type case_exprlist {ExprList*}
%destructor case_exprlist {sqlite3ExprListDelete(pParse->db, $$);}
case_exprlist(A) ::= case_exprlist(X) WHEN expr(Y) THEN expr(Z). {
  A = sqlite3ExprListAppend(pParse,X, Y.pExpr);
  A = sqlite3ExprListAppend(pParse,A, Z.pExpr);
}
case_exprlist(A) ::= WHEN expr(Y) THEN expr(Z). {
  A = sqlite3ExprListAppend(pParse,0, Y.pExpr);
  A = sqlite3ExprListAppend(pParse,A, Z.pExpr);
}
%type case_else {Expr*}
%destructor case_else {sqlite3ExprDelete(pParse->db, $$);}
case_else(A) ::=  ELSE expr(X).         {A = X.pExpr;}
case_else(A) ::=  .                     {A = 0;} 
%type case_operand {Expr*}
%destructor case_operand {sqlite3ExprDelete(pParse->db, $$);}
case_operand(A) ::= expr(X).            {A = X.pExpr;} 
case_operand(A) ::= .                   {A = 0;} 

%type exprlist {ExprList*}
%destructor exprlist {sqlite3ExprListDelete(pParse->db, $$);}
%type nexprlist {ExprList*}
%destructor nexprlist {sqlite3ExprListDelete(pParse->db, $$);}

exprlist(A) ::= nexprlist(X).                {A = X;}
exprlist(A) ::= .                            {A = 0;}
nexprlist(A) ::= nexprlist(X) COMMA expr(Y).
    {A = sqlite3ExprListAppend(pParse,X,Y.pExpr);}
nexprlist(A) ::= expr(Y).
    {A = sqlite3ExprListAppend(pParse,0,Y.pExpr);}


///////////////////////////// The CREATE INDEX command ///////////////////////
//
cmd ::= createkw(S) uniqueflag(U) INDEX ifnotexists(NE) nm(X) dbnm(D)
        ON nm(Y) LP idxlist(Z) RP(E). {
  sqlite3CreateIndex(pParse, &X, &D, 
                     sqlite3SrcListAppend(pParse->db,0,&Y,0), Z, U,
                      &S, &E, SQLITE_SO_ASC, NE);
}

%type uniqueflag {int}
uniqueflag(A) ::= UNIQUE.  {A = OE_Abort;}
uniqueflag(A) ::= .        {A = OE_None;}

%type idxlist {ExprList*}
%destructor idxlist {sqlite3ExprListDelete(pParse->db, $$);}
%type idxlist_opt {ExprList*}
%destructor idxlist_opt {sqlite3ExprListDelete(pParse->db, $$);}

idxlist_opt(A) ::= .                         {A = 0;}
idxlist_opt(A) ::= LP idxlist(X) RP.         {A = X;}
idxlist(A) ::= idxlist(X) COMMA nm(Y) collate(C) sortorder(Z).  {
  Expr *p = 0;
  if( C.n>0 ){
    p = sqlite3Expr(pParse->db, TK_COLUMN, 0);
    sqlite3ExprSetCollByToken(pParse, p, &C);
  }
  A = sqlite3ExprListAppend(pParse,X, p);
  sqlite3ExprListSetName(pParse,A,&Y,1);
  sqlite3ExprListCheckLength(pParse, A, "index");
  if( A ) A->a[A->nExpr-1].sortOrder = (u8)Z;
}
idxlist(A) ::= nm(Y) collate(C) sortorder(Z). {
  Expr *p = 0;
  if( C.n>0 ){
    p = sqlite3PExpr(pParse, TK_COLUMN, 0, 0, 0);
    sqlite3ExprSetCollByToken(pParse, p, &C);
  }
  A = sqlite3ExprListAppend(pParse,0, p);
  sqlite3ExprListSetName(pParse, A, &Y, 1);
  sqlite3ExprListCheckLength(pParse, A, "index");
  if( A ) A->a[A->nExpr-1].sortOrder = (u8)Z;
}

%type collate {Token}
collate(C) ::= .                 {C.z = 0; C.n = 0;}
collate(C) ::= COLLATE ids(X).   {C = X;}


///////////////////////////// The DROP INDEX command /////////////////////////
//
cmd ::= DROP INDEX ifexists(E) fullname(X).   {sqlite3DropIndex(pParse, X, E);}

///////////////////////////// The VACUUM command /////////////////////////////
//
%ifndef SQLITE_OMIT_VACUUM
%ifndef SQLITE_OMIT_ATTACH
cmd ::= VACUUM.                {sqlite3Vacuum(pParse);}
cmd ::= VACUUM nm.             {sqlite3Vacuum(pParse);}
%endif  SQLITE_OMIT_ATTACH
%endif  SQLITE_OMIT_VACUUM

///////////////////////////// The PRAGMA command /////////////////////////////
//
%ifndef SQLITE_OMIT_PRAGMA
cmd ::= PRAGMA nm(X) dbnm(Z).                {sqlite3Pragma(pParse,&X,&Z,0,0);}
cmd ::= PRAGMA nm(X) dbnm(Z) EQ nmnum(Y).    {sqlite3Pragma(pParse,&X,&Z,&Y,0);}
cmd ::= PRAGMA nm(X) dbnm(Z) LP nmnum(Y) RP. {sqlite3Pragma(pParse,&X,&Z,&Y,0);}
cmd ::= PRAGMA nm(X) dbnm(Z) EQ minus_num(Y). 
                                             {sqlite3Pragma(pParse,&X,&Z,&Y,1);}
cmd ::= PRAGMA nm(X) dbnm(Z) LP minus_num(Y) RP.
                                             {sqlite3Pragma(pParse,&X,&Z,&Y,1);}

nmnum(A) ::= plus_num(X).             {A = X;}
nmnum(A) ::= nm(X).                   {A = X;}
nmnum(A) ::= ON(X).                   {A = X;}
nmnum(A) ::= DELETE(X).               {A = X;}
nmnum(A) ::= DEFAULT(X).              {A = X;}
%endif SQLITE_OMIT_PRAGMA
plus_num(A) ::= PLUS number(X).       {A = X;}
plus_num(A) ::= number(X).            {A = X;}
minus_num(A) ::= MINUS number(X).     {A = X;}
number(A) ::= INTEGER|FLOAT(X).       {A = X;}

//////////////////////////// The CREATE TRIGGER command /////////////////////

%ifndef SQLITE_OMIT_TRIGGER

cmd ::= createkw trigger_decl(A) BEGIN trigger_cmd_list(S) END(Z). {
  Token all;
  all.z = A.z;
  all.n = (int)(Z.z - A.z) + Z.n;
  sqlite3FinishTrigger(pParse, S, &all);
}

trigger_decl(A) ::= temp(T) TRIGGER ifnotexists(NOERR) nm(B) dbnm(Z) 
                    trigger_time(C) trigger_event(D)
                    ON fullname(E) foreach_clause when_clause(G). {
  sqlite3BeginTrigger(pParse, &B, &Z, C, D.a, D.b, E, G, T, NOERR);
  A = (Z.n==0?B:Z);
}

%type trigger_time {int}
trigger_time(A) ::= BEFORE.      { A = TK_BEFORE; }
trigger_time(A) ::= AFTER.       { A = TK_AFTER;  }
trigger_time(A) ::= INSTEAD OF.  { A = TK_INSTEAD;}
trigger_time(A) ::= .            { A = TK_BEFORE; }

%type trigger_event {struct TrigEvent}
%destructor trigger_event {sqlite3IdListDelete(pParse->db, $$.b);}
trigger_event(A) ::= DELETE|INSERT(OP).       {A.a = @OP; A.b = 0;}
trigger_event(A) ::= UPDATE(OP).              {A.a = @OP; A.b = 0;}
trigger_event(A) ::= UPDATE OF inscollist(X). {A.a = TK_UPDATE; A.b = X;}

foreach_clause ::= .
foreach_clause ::= FOR EACH ROW.

%type when_clause {Expr*}
%destructor when_clause {sqlite3ExprDelete(pParse->db, $$);}
when_clause(A) ::= .             { A = 0; }
when_clause(A) ::= WHEN expr(X). { A = X.pExpr; }

%type trigger_cmd_list {TriggerStep*}
%destructor trigger_cmd_list {sqlite3DeleteTriggerStep(pParse->db, $$);}
trigger_cmd_list(A) ::= trigger_cmd_list(Y) trigger_cmd(X) SEMI. {
  assert( Y!=0 );
  Y->pLast->pNext = X;
  Y->pLast = X;
  A = Y;
}
trigger_cmd_list(A) ::= trigger_cmd(X) SEMI. { 
  assert( X!=0 );
  X->pLast = X;
  A = X;
}

// Disallow qualified table names on INSERT, UPDATE, and DELETE statements
// within a trigger.  The table to INSERT, UPDATE, or DELETE is always in 
// the same database as the table that the trigger fires on.
//
%type trnm {Token}
trnm(A) ::= nm(X).   {A = X;}
trnm(A) ::= nm DOT nm(X). {
  A = X;
  sqlite3ErrorMsg(pParse, 
        "qualified table names are not allowed on INSERT, UPDATE, and DELETE "
        "statements within triggers");
}

// Disallow the INDEX BY and NOT INDEXED clauses on UPDATE and DELETE
// statements within triggers.  We make a specific error message for this
// since it is an exception to the default grammar rules.
//
tridxby ::= .
tridxby ::= INDEXED BY nm. {
  sqlite3ErrorMsg(pParse,
        "the INDEXED BY clause is not allowed on UPDATE or DELETE statements "
        "within triggers");
}
tridxby ::= NOT INDEXED. {
  sqlite3ErrorMsg(pParse,
        "the NOT INDEXED clause is not allowed on UPDATE or DELETE statements "
        "within triggers");
}



%type trigger_cmd {TriggerStep*}
%destructor trigger_cmd {sqlite3DeleteTriggerStep(pParse->db, $$);}
// 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) inscollist_opt(F) valuelist(Y).
   {A = sqlite3TriggerInsertStep(pParse->db, &X, F, Y.pList, Y.pSelect, R);}

trigger_cmd(A) ::= insert_cmd(R) INTO trnm(X) inscollist_opt(F) select(S).
               {A = sqlite3TriggerInsertStep(pParse->db, &X, F, 0, 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).  {A = sqlite3TriggerSelectStep(pParse->db, X); }

// The special RAISE expression that may occur in trigger programs
expr(A) ::= RAISE(X) LP IGNORE RP(Y).  {
  A.pExpr = sqlite3PExpr(pParse, TK_RAISE, 0, 0, 0); 
  if( A.pExpr ){
    A.pExpr->affinity = OE_Ignore;
  }
  A.zStart = X.z;
  A.zEnd = &Y.z[Y.n];
}
expr(A) ::= RAISE(X) LP raisetype(T) COMMA nm(Z) RP(Y).  {
  A.pExpr = sqlite3PExpr(pParse, TK_RAISE, 0, 0, &Z); 
  if( A.pExpr ) {
    A.pExpr->affinity = (char)T;
  }
  A.zStart = X.z;
  A.zEnd = &Y.z[Y.n];
}
%endif  !SQLITE_OMIT_TRIGGER

%type raisetype {int}
raisetype(A) ::= ROLLBACK.  {A = OE_Rollback;}
raisetype(A) ::= ABORT.     {A = OE_Abort;}
raisetype(A) ::= FAIL.      {A = OE_Fail;}


////////////////////////  DROP TRIGGER statement //////////////////////////////
%ifndef SQLITE_OMIT_TRIGGER
cmd ::= DROP TRIGGER ifexists(NOERR) fullname(X). {
  sqlite3DropTrigger(pParse,X,NOERR);
}
%endif  !SQLITE_OMIT_TRIGGER

//////////////////////// ATTACH DATABASE file AS name /////////////////////////
%ifndef SQLITE_OMIT_ATTACH
cmd ::= ATTACH database_kw_opt expr(F) AS expr(D) key_opt(K). {
  sqlite3Attach(pParse, F.pExpr, D.pExpr, K);
}
cmd ::= DETACH database_kw_opt expr(D). {
  sqlite3Detach(pParse, D.pExpr);
}

%type key_opt {Expr*}
%destructor key_opt {sqlite3ExprDelete(pParse->db, $$);}
key_opt(A) ::= .                     { A = 0; }
key_opt(A) ::= KEY expr(X).          { A = X.pExpr; }

database_kw_opt ::= DATABASE.
database_kw_opt ::= .
%endif SQLITE_OMIT_ATTACH

////////////////////////// REINDEX collation //////////////////////////////////
%ifndef SQLITE_OMIT_REINDEX
cmd ::= REINDEX.                {sqlite3Reindex(pParse, 0, 0);}
cmd ::= REINDEX nm(X) dbnm(Y).  {sqlite3Reindex(pParse, &X, &Y);}
%endif  SQLITE_OMIT_REINDEX

/////////////////////////////////// ANALYZE ///////////////////////////////////
%ifndef SQLITE_OMIT_ANALYZE
cmd ::= ANALYZE.                {sqlite3Analyze(pParse, 0, 0);}
cmd ::= ANALYZE nm(X) dbnm(Y).  {sqlite3Analyze(pParse, &X, &Y);}
%endif

//////////////////////// ALTER TABLE table ... ////////////////////////////////
%ifndef SQLITE_OMIT_ALTERTABLE
cmd ::= ALTER TABLE fullname(X) RENAME TO nm(Z). {
  sqlite3AlterRenameTable(pParse,X,&Z);
}
cmd ::= ALTER TABLE add_column_fullname ADD kwcolumn_opt column(Y). {
  sqlite3AlterFinishAddColumn(pParse, &Y);
}
add_column_fullname ::= fullname(X). {
  pParse->db->lookaside.bEnabled = 0;
  sqlite3AlterBeginAddColumn(pParse, X);
}
kwcolumn_opt ::= .
kwcolumn_opt ::= COLUMNKW.
%endif  SQLITE_OMIT_ALTERTABLE

//////////////////////// CREATE VIRTUAL TABLE ... /////////////////////////////
%ifndef SQLITE_OMIT_VIRTUALTABLE
cmd ::= create_vtab.                       {sqlite3VtabFinishParse(pParse,0);}
cmd ::= create_vtab LP vtabarglist RP(X).  {sqlite3VtabFinishParse(pParse,&X);}
create_vtab ::= createkw VIRTUAL TABLE ifnotexists(E)
                nm(X) dbnm(Y) USING nm(Z). {
    sqlite3VtabBeginParse(pParse, &X, &Y, &Z, E);
}
vtabarglist ::= vtabarg.
vtabarglist ::= vtabarglist COMMA vtabarg.
vtabarg ::= .                       {sqlite3VtabArgInit(pParse);}
vtabarg ::= vtabarg vtabargtoken.
vtabargtoken ::= ANY(X).            {sqlite3VtabArgExtend(pParse,&X);}
vtabargtoken ::= lp anylist RP(X).  {sqlite3VtabArgExtend(pParse,&X);}
lp ::= LP(X).                       {sqlite3VtabArgExtend(pParse,&X);}
anylist ::= .
anylist ::= anylist LP anylist RP.
anylist ::= anylist ANY.
%endif  SQLITE_OMIT_VIRTUALTABLE