SQLite

  UNUSED_PARAMETER(NotUsed);
  pWalker->eCode = 0;
  return WRC_Abort;
}

/*
** If the input expression is an ID with the name "true" or "false"
** then convert it into an TK_TRUEFALSE term.  Return non-zero if
** the conversion happened, and zero if the expression is unaltered.
*/
int sqlite3ExprIdToTrueFalse(Expr *pExpr){
  assert( pExpr->op==TK_ID || pExpr->op==TK_STRING );
  if( sqlite3StrICmp(pExpr->u.zToken, "true")==0
   || sqlite3StrICmp(pExpr->u.zToken, "false")==0
  ){
    pExpr->op = TK_TRUEFALSE;
    return 1;
  }
  return 0;
}

/*
** The argument must be a TK_TRUEFALSE Expr node.  Return 1 if it is TRUE
** and 0 if it is FALSE.
*/
int sqlite3ExprTruthValue(const Expr *pExpr){
  assert( pExpr->op==TK_TRUEFALSE );
  assert( sqlite3StrICmp(pExpr->u.zToken,"true")==0
       || sqlite3StrICmp(pExpr->u.zToken,"false")==0 );
  return pExpr->u.zToken[4]==0;
}

                               pExpr->op2);
    }
    case TK_INTEGER: {
      codeInteger(pParse, pExpr, 0, target);
      return target;
    }
    case TK_TRUEFALSE: {
      sqlite3VdbeAddOp2(v, OP_Integer, sqlite3ExprTruthValue(pExpr), target);
      return target;
    }
#ifndef SQLITE_OMIT_FLOATING_POINT
    case TK_FLOAT: {
      assert( !ExprHasProperty(pExpr, EP_IntValue) );
      codeReal(v, pExpr->u.zToken, 0, target);
      return target;

      assert( TK_NOT==OP_Not );         testcase( op==TK_NOT );
      r1 = sqlite3ExprCodeTemp(pParse, pExpr->pLeft, &regFree1);
      testcase( regFree1==0 );
      sqlite3VdbeAddOp2(v, op, r1, inReg);
      break;
    }
    case TK_TRUTH: {
      int isTrue;    /* IS TRUE or IS NOT TRUE */
      int bNormal;   /* IS TRUE or IS FALSE */
      r1 = sqlite3ExprCodeTemp(pParse, pExpr->pLeft, &regFree1);
      testcase( regFree1==0 );
      isTrue = sqlite3ExprTruthValue(pExpr->pRight);
      bNormal = pExpr->op2==TK_IS;
      testcase( isTrue && bNormal);
      testcase( !isTrue && bNormal);
      sqlite3VdbeAddOp4Int(v, OP_IsTrue, r1, inReg, !isTrue, isTrue ^ bNormal);

      break;
    }
    case TK_ISNULL:
    case TK_NOTNULL: {
      int addr;
      assert( TK_ISNULL==OP_IsNull );   testcase( op==TK_ISNULL );
      assert( TK_NOTNULL==OP_NotNull ); testcase( op==TK_NOTNULL );

    }
    case TK_NOT: {
      testcase( jumpIfNull==0 );
      sqlite3ExprIfFalse(pParse, pExpr->pLeft, dest, jumpIfNull);
      break;
    }
    case TK_TRUTH: {
      int isNot;      /* IS NOT TRUE or IS NOT FALSE */
      int isTrue;     /* IS TRUE or IS NOT TRUE */
      testcase( jumpIfNull==0 );
      isNot = pExpr->op2==TK_ISNOT;
      isTrue = sqlite3ExprTruthValue(pExpr->pRight);
      testcase( isTrue && isNot );
      testcase( !isTrue && isNot );
      if( isTrue ^ isNot ){
        sqlite3ExprIfTrue(pParse, pExpr->pLeft, dest,
                          isNot ? SQLITE_JUMPIFNULL : 0);
      }else{
        sqlite3ExprIfFalse(pParse, pExpr->pLeft, dest,
                           isNot ? SQLITE_JUMPIFNULL : 0);
      }

    }
    case TK_NOT: {
      testcase( jumpIfNull==0 );
      sqlite3ExprIfTrue(pParse, pExpr->pLeft, dest, jumpIfNull);
      break;
    }
    case TK_TRUTH: {
      int isNot;   /* IS NOT TRUE or IS NOT FALSE */
      int isTrue;  /* IS TRUE or IS NOT TRUE */
      testcase( jumpIfNull==0 );

      isNot = pExpr->op2==TK_ISNOT;
      isTrue = sqlite3ExprTruthValue(pExpr->pRight);
      testcase( isTrue && isNot );
      testcase( !isTrue && isNot );
      if( isTrue ^ isNot ){
        /* IS TRUE and IS NOT FALSE */
        sqlite3ExprIfFalse(pParse, pExpr->pLeft, dest,
                           isNot ? 0 : SQLITE_JUMPIFNULL);

      }else{
        /* IS FALSE and IS NOT TRUE */
        sqlite3ExprIfTrue(pParse, pExpr->pLeft, dest,
                          isNot ? 0 : SQLITE_JUMPIFNULL);
      }
      break;
    }
    case TK_IS:
    case TK_ISNOT:
      testcase( pExpr->op==TK_IS );
      testcase( pExpr->op==TK_ISNOT );

ccons ::= DEFAULT MINUS(A) term(X) scanpt(Z).      {
  Expr *p = sqlite3PExpr(pParse, TK_UMINUS, X, 0);
  sqlite3AddDefaultValue(pParse,p,A.z,Z);
}
ccons ::= DEFAULT scanpt id(X).       {
  Expr *p = tokenExpr(pParse, TK_STRING, X);
  sqlite3ExprIdToTrueFalse(p);
  testcase( p->op==TK_TRUEFALSE && sqlite3ExprTruthValue(p) );
  sqlite3AddDefaultValue(pParse,p,X.z,X.z+X.n);
}

// In addition to the type name, we also care about the primary key and
// UNIQUE constraints.
//
ccons ::= NULL onconf.

void sqlite3CodeVerifyNamedSchema(Parse*, const char *zDb);
void sqlite3BeginTransaction(Parse*, int);
void sqlite3EndTransaction(Parse*,int);
void sqlite3Savepoint(Parse*, int, Token*);
void sqlite3CloseSavepoints(sqlite3 *);
void sqlite3LeaveMutexAndCloseZombie(sqlite3*);
int sqlite3ExprIdToTrueFalse(Expr*);
int sqlite3ExprTruthValue(const Expr*);
int sqlite3ExprIsConstant(Expr*);
int sqlite3ExprIsConstantNotJoin(Expr*);
int sqlite3ExprIsConstantOrFunction(Expr*, u8);
int sqlite3ExprIsConstantOrGroupBy(Parse*, Expr*, ExprList*);
int sqlite3ExprIsTableConstant(Expr*,int);
#ifdef SQLITE_ENABLE_CURSOR_HINTS
int sqlite3ExprContainsSubquery(Expr*);

    }
    case TK_NULL: {
      sqlite3TreeViewLine(pView,"NULL");
      break;
    }
    case TK_TRUEFALSE: {
      sqlite3TreeViewLine(pView,
         sqlite3ExprTruthValue(pExpr) ? "TRUE" : "FALSE");
      break;
    }
#ifndef SQLITE_OMIT_BLOB_LITERAL
    case TK_BLOB: {
      sqlite3TreeViewLine(pView,"%s", pExpr->u.zToken);
      break;
    }

      int x;
      const char *azOp[] = {
         "IS-FALSE", "IS-TRUE", "IS-NOT-FALSE", "IS-NOT-TRUE"
      };
      assert( pExpr->op2==TK_IS || pExpr->op2==TK_ISNOT );
      assert( pExpr->pRight );
      assert( pExpr->pRight->op==TK_TRUEFALSE );
      x = (pExpr->op2==TK_ISNOT)*2 + sqlite3ExprTruthValue(pExpr->pRight);
      zUniOp = azOp[x];
      break;
    }

    case TK_SPAN: {
      sqlite3TreeViewLine(pView, "SPAN %Q", pExpr->u.zToken);
      sqlite3TreeViewExpr(pView, pExpr->pLeft, 0);

/* Opcode: IsTrue P1 P2 P3 P4 *
** Synopsis: r[P2] = coalesce(r[P1]==TRUE,P3) ^ P4
**
** This opcode implements the IS TRUE, IS FALSE, IS NOT TRUE, and
** IS NOT FALSE operators.
**
** Interpret the value in register P1 as a boolean value.  Store that
** boolean (a 0 or 1) in register P2.  Or if the value in register P1 is 
** NULL, then the P3 is stored in register P2.  Invert the answer if P4
** is 1.
**
** The logic is summarized like this:
**
** <ul> 
** <li> If P3==0 and P4==0  then  r[P2] := r[P1] IS TRUE
** <li> If P3==1 and P4==1  then  r[P2] := r[P1] IS FALSE
** <li> If P3==0 and P4==1  then  r[P2] := r[P1] IS NOT TRUE
** <li> If P3==1 and P4==0  then  r[P2] := r[P1] IS NOT FALSE
** </ul>
*/
case OP_IsTrue: {               /* in1, out2 */
  assert( pOp->p4type==P4_INT32 );
  assert( pOp->p4.i==0 || pOp->p4.i==1 );
  assert( pOp->p3==0 || pOp->p3==1 );
  sqlite3VdbeMemSetInt64(&aMem[pOp->p2],
      sqlite3VdbeBooleanValue(&aMem[pOp->p1], pOp->p3) ^ pOp->p4.i);
  break;
}

/* Opcode: Not P1 P2 * * *
** Synopsis: r[P2]= !r[P1]