func newSargDefault(expr expression.Expression) *sargDefault {
var spans Spans
if expr.PropagatesNull() {
spans = _VALUED_SPANS
} else if expr.PropagatesMissing() {
spans = _FULL_SPANS
}
rv := &sargDefault{}
rv.sarg = func(expr2 expression.Expression) (Spans, error) {
if expr.EquivalentTo(expr2) {
return _SELF_SPANS, nil
}
if spans != nil && expr.DependsOn(expr2) {
return _VALUED_SPANS, nil
}
if spans != nil && expr.DependsOn(expr2) {
return _FULL_SPANS, nil
}
return nil, nil
}
return rv
}
func LessThan(expr1, expr2 expression.Expression) bool {
value1 := expr1.Value()
value2 := expr2.Value()
return value1 != nil && value2 != nil &&
value1.Collate(value2) < 0
}
func (this *NNF) VisitFunction(expr expression.Function) (interface{}, error) {
var exp expression.Expression = expr
switch expr := expr.(type) {
case *expression.IsBoolean:
exp = expression.NewLE(expr.Operand(), expression.TRUE_EXPR)
case *expression.IsNumber:
exp = expression.NewAnd(
expression.NewGT(expr.Operand(), expression.TRUE_EXPR),
expression.NewLT(expr.Operand(), expression.EMPTY_STRING_EXPR))
case *expression.IsString:
exp = expression.NewAnd(
expression.NewGE(expr.Operand(), expression.EMPTY_STRING_EXPR),
expression.NewLT(expr.Operand(), expression.EMPTY_ARRAY_EXPR))
case *expression.IsArray:
exp = expression.NewAnd(
expression.NewGE(expr.Operand(), expression.EMPTY_ARRAY_EXPR),
expression.NewLT(expr.Operand(), _EMPTY_OBJECT_EXPR))
case *expression.IsObject:
// Not equivalent to IS OBJECT. Includes BINARY values.
exp = expression.NewGE(expr.Operand(), _EMPTY_OBJECT_EXPR)
}
return exp, exp.MapChildren(this)
}
func (this *JSConverter) Visit(expr expression.Expression) string {
var buf bytes.Buffer
s, err := expr.Accept(this)
if err != nil {
panic(fmt.Sprintf("Unexpected error in JSConverter: %v", err))
}
switch s := s.(type) {
case []byte:
buf.WriteString(string(s))
for this.stack.Size() != 0 {
funcExpr := this.stack.Pop().(*funcExpr)
buf.WriteString(funcExpr.name)
if funcExpr.operands.Front() != nil {
buf.WriteString(writeOperands(funcExpr.operands))
}
}
default:
buf.WriteString(s.(string))
}
// if the stack is not empty, pop the function
/*
for this.stack.Size() != 0 {
funcExpr := this.stack.Pop().(*funcExpr)
buf.WriteString(funcExpr.name)
if funcExpr.operands.Front() != nil {
buf.WriteString(writeOperands(funcExpr.operands))
}
}
*/
return buf.String()
}
/*
The function NewExecute returns a pointer to the Execute
struct with the input argument expressions value as a field.
*/
func NewExecute(prepared expression.Expression) *Execute {
rv := &Execute{
prepared: prepared.Value(),
}
rv.stmt = rv
return rv
}
func newSargableDefault(expr expression.Expression) *sargableDefault {
rv := &sargableDefault{}
rv.test = func(expr2 expression.Expression) (bool, error) {
return expr.EquivalentTo(expr2), nil
}
return rv
}
func SargableFor(expr1, expr2 expression.Expression) bool {
if expr2.Value() != nil {
return false
}
s := newSargable(expr1)
result, _ := expr2.Accept(s)
return result.(bool)
}
func SubsetOf(expr1, expr2 expression.Expression) bool {
v2 := expr2.Value()
if v2 != nil {
return v2.Truth()
}
s := newSubset(expr1)
result, _ := expr2.Accept(s)
return result.(bool)
}
func SargFor(expr1, expr2 expression.Expression) Spans {
if expr2.Value() != nil {
return nil
}
s := newSarg(expr1)
result, _ := expr2.Accept(s)
if result != nil {
return result.(Spans)
}
return nil
}
/*
Create a key value pair using the operands of the input
expression Array construct and return.
*/
func NewPair(expr expression.Expression) (*Pair, error) {
array, ok := expr.(*expression.ArrayConstruct)
if !ok {
return nil, fmt.Errorf("Invalid VALUES expression %s", expr.String())
}
operands := array.Operands()
if len(operands) != 2 {
return nil, fmt.Errorf("Invalid VALUES expression %s", expr.String())
}
pair := &Pair{
Key: operands[0],
Value: operands[1],
}
return pair, nil
}
func (this *NNF) VisitNot(expr *expression.Not) (interface{}, error) {
err := expr.MapChildren(this)
if err != nil {
return nil, err
}
var exp expression.Expression = expr
switch operand := expr.Operand().(type) {
case *expression.Not:
exp = operand.Operand()
case *expression.And:
operands := make(expression.Expressions, len(operand.Operands()))
for i, op := range operand.Operands() {
operands[i] = expression.NewNot(op)
}
exp = expression.NewOr(operands...)
case *expression.Or:
operands := make(expression.Expressions, len(operand.Operands()))
for i, op := range operand.Operands() {
operands[i] = expression.NewNot(op)
}
exp = expression.NewAnd(operands...)
case *expression.Eq:
exp = expression.NewOr(expression.NewLT(operand.First(), operand.Second()),
expression.NewLT(operand.Second(), operand.First()))
case *expression.LT:
exp = expression.NewLE(operand.Second(), operand.First())
case *expression.LE:
exp = expression.NewLT(operand.Second(), operand.First())
}
return exp, exp.MapChildren(this)
}
func LessThanOrEquals(expr1, expr2 expression.Expression) bool {
return LessThan(expr1, expr2) || expr1.EquivalentTo(expr2)
}
func newSarg(expr expression.Expression) expression.Visitor {
s, _ := expr.Accept(_SARG_FACTORY)
return s.(expression.Visitor)
}
func newSubsetDefault(expr expression.Expression) *subsetDefault {
rv := &subsetDefault{}
rv.test = func(expr2 expression.Expression) (bool, error) {
value2 := expr2.Value()
if value2 != nil {
return value2.Truth(), nil
}
if expr.EquivalentTo(expr2) {
return true, nil
}
switch expr2 := expr2.(type) {
case *expression.And:
for _, op := range expr2.Operands() {
if !SubsetOf(expr, op) {
return false, nil
}
}
return true, nil
case *expression.Or:
for _, op := range expr2.Operands() {
if SubsetOf(expr, op) {
return true, nil
}
}
return false, nil
case *expression.IsNotMissing:
return expr.PropagatesMissing() &&
expr.DependsOn(expr2.Operand()), nil
case *expression.IsNotNull:
return expr.PropagatesNull() &&
expr.DependsOn(expr2.Operand()), nil
case *expression.IsValued:
return expr.PropagatesNull() &&
expr.DependsOn(expr2.Operand()), nil
}
return false, nil
}
return rv
}
func newSubset(expr expression.Expression) expression.Visitor {
s, _ := expr.Accept(_SUBSET_FACTORY)
return s.(expression.Visitor)
}