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Index ¶
Constants ¶
This section is empty.
Variables ¶
var ErrInvalidResult = errors.New("expression must evaluate to an object")
ErrInvalidResult is returned when an expression supposed to evaluate to an object returns something else.
var ErrStreamClosed = errors.New("stream closed")
ErrStreamClosed is used to indicate that a stream must be closed.
Functions ¶
This section is empty.
Types ¶
type BaseOperator ¶
func (*BaseOperator) GetNext ¶
func (op *BaseOperator) GetNext() Operator
func (*BaseOperator) GetPrev ¶
func (op *BaseOperator) GetPrev() Operator
func (*BaseOperator) SetNext ¶
func (op *BaseOperator) SetNext(o Operator)
func (*BaseOperator) SetPrev ¶
func (op *BaseOperator) SetPrev(o Operator)
type ConcatOperator ¶
type ConcatOperator struct {
BaseOperator
Streams []*Stream
}
A ConcatOperator concatenates two streams.
func Concat ¶
func Concat(s ...*Stream) *ConcatOperator
Concat turns two individual streams into one.
func (*ConcatOperator) Iterate ¶
func (it *ConcatOperator) Iterate(in *environment.Environment, fn func(*environment.Environment) error) error
func (*ConcatOperator) String ¶
func (it *ConcatOperator) String() string
type DiscardOperator ¶
type DiscardOperator struct {
BaseOperator
}
DiscardOperator is an operator that doesn't do anything.
func Discard ¶
func Discard() *DiscardOperator
Discard is an operator that doesn't produce any object. It iterates over the previous operator and discards all the objects.
func (*DiscardOperator) Iterate ¶
func (op *DiscardOperator) Iterate(in *environment.Environment, _ func(out *environment.Environment) error) (err error)
Iterate iterates over all the streams and returns their union.
func (*DiscardOperator) String ¶
func (it *DiscardOperator) String() string
type OnConflictOperator ¶
type OnConflictOperator struct {
BaseOperator
OnConflict *Stream
}
OnConflictOperator handles any conflicts that occur during the iteration.
func OnConflict ¶
func OnConflict(onConflict *Stream) *OnConflictOperator
func (*OnConflictOperator) Iterate ¶
func (op *OnConflictOperator) Iterate(in *environment.Environment, fn func(out *environment.Environment) error) error
func (*OnConflictOperator) String ¶
func (op *OnConflictOperator) String() string
type Operator ¶
type Operator interface {
Iterate(in *environment.Environment, fn func(out *environment.Environment) error) error
SetPrev(prev Operator)
SetNext(next Operator)
GetNext() Operator
GetPrev() Operator
String() string
}
An Operator is used to modify a stream. It takes an environment containing the current value as well as any other metadata created by other operators and returns a new environment which will be passed to the next operator. If it returns a nil environment, the env will be ignored. If it returns an error, the stream will be interrupted and that error will bubble up and returned by this function, unless that error is ErrStreamClosed, in which case the Iterate method will stop the iteration and return nil. Stream operators can be reused, and thus, any state or side effect should be kept within the Op closure unless the nature of the operator prevents that.
func InsertAfter ¶
func InsertBefore ¶
type OperatorFunc ¶
type OperatorFunc func(func(env *environment.Environment) error) error
An OperatorFunc is the function that will receive each value of the stream.
type Range ¶
type Range struct {
Min, Max expr.LiteralExprList
Paths []object.Path
// Exclude Min and Max from the results.
// By default, min and max are inclusive.
// Exclusive and Exact cannot be set to true at the same time.
Exclusive bool
// Used to match an exact value equal to Min.
// If set to true, Max will be ignored for comparison
// and for determining the global upper bound.
Exact bool
}
Range represents a range to select values after or before a given boundary.
func (*Range) Eval ¶
func (r *Range) Eval(env *environment.Environment) (*database.Range, error)
type Ranges ¶
type Ranges []Range
func (Ranges) Eval ¶
func (r Ranges) Eval(env *environment.Environment) ([]*database.Range, error)
Encode each range using the given value encoder.
type Stream ¶
type Stream struct {
Op Operator
}
func (*Stream) Iterate ¶
func (s *Stream) Iterate(in *environment.Environment, fn func(out *environment.Environment) error) error
type UnionOperator ¶
type UnionOperator struct {
BaseOperator
Streams []*Stream
}
UnionOperator is an operator that merges the results of multiple operators.
func (*UnionOperator) Iterate ¶
func (it *UnionOperator) Iterate(in *environment.Environment, fn func(out *environment.Environment) error) (err error)
Iterate iterates over all the streams and returns their union.
func (*UnionOperator) String ¶
func (it *UnionOperator) String() string
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