stream

package
v0.18.0 Latest Latest
Warning

This package is not in the latest version of its module.

 Go to latest Published: Nov 5, 2025 License: MIT Imports: 9 Imported by: 0

Documentation

Index

Constants

This section is empty.

Variables

View Source 
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.

View Source 
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 

type BaseOperator struct {
	Prev Operator
	Next Operator
}

func (*BaseOperator) Columns added in v0.17.0 

func (op *BaseOperator) Columns(env *environment.Environment) ([]string, error)

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 ConcatIterator added in v0.17.0 

type ConcatIterator struct {
	// contains filtered or unexported fields
}

func (*ConcatIterator) Close added in v0.17.0 

func (it *ConcatIterator) Close() error

func (*ConcatIterator) Error added in v0.17.0 

func (it *ConcatIterator) Error() error

func (*ConcatIterator) Next added in v0.17.0 

func (it *ConcatIterator) Next() bool

func (*ConcatIterator) Row added in v0.17.0 

func (it *ConcatIterator) Row() (database.Row, error)

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) Columns added in v0.17.0 

func (it *ConcatOperator) Columns(env *environment.Environment) ([]string, error)

func (*ConcatOperator) Iterator added in v0.17.0 

func (it *ConcatOperator) Iterator(in *environment.Environment) (Iterator, error)

func (*ConcatOperator) String 

func (it *ConcatOperator) String() string

type DiscardIterator added in v0.17.0 

type DiscardIterator struct {
	Iterator
}

func (*DiscardIterator) Next added in v0.17.0 

func (it *DiscardIterator) Next() bool

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 row. It iterates over the previous operator and discards all the objects.

func (*DiscardOperator) Iterator added in v0.17.0 

func (op *DiscardOperator) Iterator(in *environment.Environment) (Iterator, error)

Iterator returns an iterator which discards all rows.

func (*DiscardOperator) String 

func (it *DiscardOperator) String() string

type Iterator added in v0.17.0 

type Iterator interface {
	Close() error
	Next() bool
	Error() error
	Row() (database.Row, error)
}

type Operator 

type Operator interface {
	// Iterate(in *environment.Environment, fn func(out *environment.Environment) error) error
	Iterator(in *environment.Environment) (Iterator, error)
	SetPrev(prev Operator)
	SetNext(next Operator)
	GetNext() Operator
	GetPrev() Operator
	String() string
	Columns(env *environment.Environment) ([]string, error)
}

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 InsertAfter(op, newOp Operator) Operator

func InsertBefore 

func InsertBefore(op, newOp Operator) Operator

func Pipe 

func Pipe(ops ...Operator) Operator

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
	Columns  []string
	// 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)

func (*Range) IsEqual 

func (r *Range) IsEqual(other *Range) bool

func (*Range) String 

func (r *Range) String() string

type Ranges 

type Ranges []Range

func (Ranges) Append 

func (r Ranges) Append(rng Range) Ranges

Append rng to r and return the new slice. Duplicate ranges are ignored.

func (Ranges) Cost 

func (r Ranges) Cost() int

Cost is a best effort function to determine the cost of a range lookup.

func (Ranges) Eval 

func (r Ranges) Eval(env *environment.Environment) ([]*database.Range, error)

Encode each range using the given value encoder.

func (Ranges) String 

func (r Ranges) String() string

type RowsIterator added in v0.17.0 

type RowsIterator struct {
	// contains filtered or unexported fields
}

func (*RowsIterator) Close added in v0.17.0 

func (it *RowsIterator) Close() error

func (*RowsIterator) Env added in v0.17.0 

func (it *RowsIterator) Env() *environment.Environment

func (*RowsIterator) Error added in v0.17.0 

func (it *RowsIterator) Error() error

func (*RowsIterator) Next added in v0.17.0 

func (it *RowsIterator) Next() bool

func (*RowsIterator) Row added in v0.17.0 

func (it *RowsIterator) Row() (database.Row, error)

type RowsOperator added in v0.17.0 

type RowsOperator struct {
	BaseOperator
	Rows []database.Row
	// contains filtered or unexported fields
}

func Rows added in v0.17.0 

func Rows(columns []string, rows ...database.Row) *RowsOperator

Rows creates an operator that iterates over the given rows.

func (*RowsOperator) Columns added in v0.17.0 

func (it *RowsOperator) Columns(env *environment.Environment) ([]string, error)

func (*RowsOperator) Iterator added in v0.17.0 

func (op *RowsOperator) Iterator(in *environment.Environment) (Iterator, error)

func (*RowsOperator) String added in v0.17.0 

func (op *RowsOperator) String() string

type Stream 

type Stream struct {
	Op Operator
}

func New 

func New(op Operator) *Stream

func (*Stream) Columns added in v0.17.0 

func (s *Stream) Columns(env *environment.Environment) ([]string, error)

func (*Stream) First 

func (s *Stream) First() Operator

func (*Stream) Iterate 

func (s *Stream) Iterate(in *environment.Environment, fn func(database.Row) error) error

func (*Stream) Iterator added in v0.17.0 

func (s *Stream) Iterator(in *environment.Environment) (Iterator, error)

func (*Stream) Pipe 

func (s *Stream) Pipe(op Operator) *Stream

func (*Stream) Remove 

func (s *Stream) Remove(op Operator)

func (*Stream) String 

func (s *Stream) String() string

type UnionIterator added in v0.17.0 

type UnionIterator struct {
	// contains filtered or unexported fields
}

func (*UnionIterator) Close added in v0.17.0 

func (it *UnionIterator) Close() error

func (*UnionIterator) Error added in v0.17.0 

func (it *UnionIterator) Error() error

func (*UnionIterator) Next added in v0.17.0 

func (it *UnionIterator) Next() bool

func (*UnionIterator) Row added in v0.17.0 

func (it *UnionIterator) Row() (database.Row, error)

type UnionOperator 

type UnionOperator struct {
	BaseOperator
	Streams []*Stream
}

UnionOperator is an operator that merges the results of multiple operators.

func Union 

func Union(s ...*Stream) *UnionOperator

Union returns a new UnionOperator.

func (*UnionOperator) Columns added in v0.17.0 

func (it *UnionOperator) Columns(env *environment.Environment) ([]string, error)

func (*UnionOperator) Iterator added in v0.17.0 

func (op *UnionOperator) Iterator(in *environment.Environment) (Iterator, error)

Iterate iterates over all the streams and returns their union.

func (*UnionOperator) String 

func (it *UnionOperator) String() string

Source Files

View all Source files

Directories

Path Synopsis

Jump to

Keyboard shortcuts

? : This menu
/ : Search site
f or F : Jump to
y or Y : Canonical URL
go.dev uses cookies from Google to deliver and enhance the quality of its services and to analyze traffic. Learn more.