functions

package
v0.15.0 Latest Latest
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 Go to latest Published: Jun 27, 2022 License: MIT Imports: 8 Imported by: 0

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Constants

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Variables

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Functions

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Types

type Avg 

type Avg struct {
	Expr expr.Expr
}

Avg is the AVG aggregator function.

func (*Avg) Aggregator 

func (s *Avg) Aggregator() expr.Aggregator

Aggregator returns a Avg. It implements the AggregatorBuilder interface.

func (*Avg) Eval 

func (s *Avg) Eval(env *environment.Environment) (types.Value, error)

Eval extracts the average value from the given document and returns it.

func (*Avg) IsEqual 

func (s *Avg) IsEqual(other expr.Expr) bool

IsEqual compares this expression with the other expression and returns true if they are equal.

func (*Avg) Params 

func (s *Avg) Params() []expr.Expr

func (*Avg) String 

func (s *Avg) String() string

String returns the alias if non-zero, otherwise it returns a string representation of the average expression.

type AvgAggregator 

type AvgAggregator struct {
	Fn      *Avg
	Avg     float64
	Counter int64
}

AvgAggregator is an aggregator that returns the average non-null value.

func (*AvgAggregator) Aggregate 

func (s *AvgAggregator) Aggregate(env *environment.Environment) error

Aggregate stores the average value of all non-NULL numeric values in the group.

func (*AvgAggregator) Eval 

func (s *AvgAggregator) Eval(env *environment.Environment) (types.Value, error)

Eval returns the aggregated average as a double.

func (*AvgAggregator) String 

func (s *AvgAggregator) String() string

type Count 

type Count struct {
	Expr     expr.Expr
	Wildcard bool
	Count    int64
}

Count is the COUNT aggregator function. It counts the number of documents in a stream.

func (*Count) Aggregator 

func (c *Count) Aggregator() expr.Aggregator

Aggregator returns a CountAggregator. It implements the AggregatorBuilder interface.

func (*Count) Eval 

func (c *Count) Eval(env *environment.Environment) (types.Value, error)

func (*Count) IsEqual 

func (c *Count) IsEqual(other expr.Expr) bool

IsEqual compares this expression with the other expression and returns true if they are equal.

func (*Count) Params 

func (c *Count) Params() []expr.Expr

func (*Count) String 

func (c *Count) String() string

type CountAggregator 

type CountAggregator struct {
	Fn    *Count
	Count int64
}

CountAggregator is an aggregator that counts non-null expressions.

func (*CountAggregator) Aggregate 

func (c *CountAggregator) Aggregate(env *environment.Environment) error

Aggregate increments the counter if the count expression evaluates to a non-null value.

func (*CountAggregator) Eval 

func (c *CountAggregator) Eval(env *environment.Environment) (types.Value, error)

Eval returns the result of the aggregation as an integer.

func (*CountAggregator) String 

func (c *CountAggregator) String() string

type Definition 

type Definition interface {
	Name() string
	String() string
	Function(...expr.Expr) (expr.Function, error)
	Arity() int
}

A Definition transforms a list of expressions into a Function.

type Definitions 

type Definitions map[string]Definition

Definitions table holds a map of definition, indexed by their names.

func BuiltinDefinitions 

func BuiltinDefinitions() Definitions

BuiltinDefinitions returns a map of builtin functions.

func MathFunctions 

func MathFunctions() Definitions

MathFunctions returns all math package functions.

type Max 

type Max struct {
	Expr expr.Expr
}

Max is the MAX aggregator function.

func (*Max) Aggregator 

func (m *Max) Aggregator() expr.Aggregator

Aggregator returns a MaxAggregator. It implements the AggregatorBuilder interface.

func (*Max) Eval 

func (m *Max) Eval(env *environment.Environment) (types.Value, error)

Eval extracts the max value from the given document and returns it.

func (*Max) IsEqual 

func (m *Max) IsEqual(other expr.Expr) bool

IsEqual compares this expression with the other expression and returns true if they are equal.

func (*Max) Params 

func (m *Max) Params() []expr.Expr

func (*Max) String 

func (m *Max) String() string

String returns the alias if non-zero, otherwise it returns a string representation of the count expression.

type MaxAggregator 

type MaxAggregator struct {
	Fn  *Max
	Max types.Value
}

MaxAggregator is an aggregator that returns the minimum non-null value.

func (*MaxAggregator) Aggregate 

func (m *MaxAggregator) Aggregate(env *environment.Environment) error

Aggregate stores the maximum value. Values are compared based on their types, then if the type is equal their value is compared. Numbers are considered of the same type.

func (*MaxAggregator) Eval 

func (m *MaxAggregator) Eval(env *environment.Environment) (types.Value, error)

Eval return the maximum value.

func (*MaxAggregator) String 

func (m *MaxAggregator) String() string

type Min 

type Min struct {
	Expr expr.Expr
}

Min is the MIN aggregator function.

func (*Min) Aggregator 

func (m *Min) Aggregator() expr.Aggregator

Aggregator returns a MinAggregator. It implements the AggregatorBuilder interface.

func (*Min) Eval 

func (m *Min) Eval(env *environment.Environment) (types.Value, error)

Eval extracts the min value from the given document and returns it.

func (*Min) IsEqual 

func (m *Min) IsEqual(other expr.Expr) bool

IsEqual compares this expression with the other expression and returns true if they are equal.

func (*Min) Params 

func (m *Min) Params() []expr.Expr

func (*Min) String 

func (m *Min) String() string

String returns the alias if non-zero, otherwise it returns a string representation of the count expression.

type MinAggregator 

type MinAggregator struct {
	Fn  *Min
	Min types.Value
}

MinAggregator is an aggregator that returns the minimum non-null value.

func (*MinAggregator) Aggregate 

func (m *MinAggregator) Aggregate(env *environment.Environment) error

Aggregate stores the minimum value. Values are compared based on their types, then if the type is equal their value is compared. Numbers are considered of the same type.

func (*MinAggregator) Eval 

func (m *MinAggregator) Eval(env *environment.Environment) (types.Value, error)

Eval return the minimum value.

func (*MinAggregator) String 

func (m *MinAggregator) String() string

type PK 

type PK struct{}

PK represents the pk() function. It returns the primary key of the current document.

func (*PK) Eval 

func (k *PK) Eval(env *environment.Environment) (types.Value, error)

Eval returns the primary key of the current document.

func (*PK) IsEqual 

func (k *PK) IsEqual(other expr.Expr) bool

IsEqual compares this expression with the other expression and returns true if they are equal.

func (*PK) Params 

func (*PK) Params() []expr.Expr

func (*PK) String 

func (k *PK) String() string

type Packages 

type Packages map[string]Definitions

Packages represent a table of SQL functions grouped by their packages

func DefaultPackages 

func DefaultPackages() Packages

func (Packages) GetFunc 

func (t Packages) GetFunc(pkg string, fname string) (Definition, error)

GetFunc return a function definition by its package and name.

type ScalarDefinition 

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

A ScalarDefinition is the definition type for functions which operates on scalar values in contrast to other SQL functions such as the SUM aggregator wich operates on expressions instead.

This difference allows to simply define them with a CallFn function that takes multiple document.Value and return another types.Value, rather than having to manually evaluate expressions (see Definition).

func NewScalarDefinition 

func NewScalarDefinition(name string, arity int, callFn func(...types.Value) (types.Value, error)) *ScalarDefinition

func (*ScalarDefinition) Arity 

func (fd *ScalarDefinition) Arity() int

Arity returns the arity of the defined function.

func (*ScalarDefinition) Function 

func (fd *ScalarDefinition) Function(args ...expr.Expr) (expr.Function, error)

Function returns a Function expr node.

func (*ScalarDefinition) Name 

func (fd *ScalarDefinition) Name() string

Name returns the defined function named (as an ident, so no parentheses).

func (*ScalarDefinition) String 

func (fd *ScalarDefinition) String() string

String returns the defined function name and its arguments.

type ScalarFunction 

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

A ScalarFunction is a function which operates on scalar values in contrast to other SQL functions such as the SUM aggregator wich operates on expressions instead.

func (*ScalarFunction) Eval 

func (sf *ScalarFunction) Eval(env *environment.Environment) (types.Value, error)

Eval returns a document.Value based on the given environment and the underlying function definition.

func (*ScalarFunction) Params 

func (sf *ScalarFunction) Params() []expr.Expr

Params return the function arguments.

func (*ScalarFunction) String 

func (sf *ScalarFunction) String() string

String returns a string represention of the function expression and its arguments.

type Sum 

type Sum struct {
	Expr expr.Expr
}

Sum is the SUM aggregator function.

func (*Sum) Aggregator 

func (s *Sum) Aggregator() expr.Aggregator

Aggregator returns a Sum. It implements the AggregatorBuilder interface.

func (*Sum) Eval 

func (s *Sum) Eval(env *environment.Environment) (types.Value, error)

Eval extracts the sum value from the given document and returns it.

func (*Sum) IsEqual 

func (s *Sum) IsEqual(other expr.Expr) bool

IsEqual compares this expression with the other expression and returns true if they are equal.

func (*Sum) Params 

func (s *Sum) Params() []expr.Expr

func (*Sum) String 

func (s *Sum) String() string

String returns the alias if non-zero, otherwise it returns a string representation of the count expression.

type SumAggregator 

type SumAggregator struct {
	Fn   *Sum
	SumI *int64
	SumF *float64
}

SumAggregator is an aggregator that returns the minimum non-null value.

func (*SumAggregator) Aggregate 

func (s *SumAggregator) Aggregate(env *environment.Environment) error

Aggregate stores the sum of all non-NULL numeric values in the group. The result is an integer value if all summed values are integers. If any of the value is a double, the returned result will be a double.

func (*SumAggregator) Eval 

func (s *SumAggregator) Eval(env *environment.Environment) (types.Value, error)

Eval return the aggregated sum.

func (*SumAggregator) String 

func (s *SumAggregator) String() string

type TypeOf added in v0.14.0 

type TypeOf struct {
	Expr expr.Expr
}

func (*TypeOf) Eval added in v0.14.0 

func (t *TypeOf) Eval(env *environment.Environment) (types.Value, error)

func (*TypeOf) IsEqual added in v0.14.0 

func (t *TypeOf) IsEqual(other expr.Expr) bool

IsEqual compares this expression with the other expression and returns true if they are equal.

func (*TypeOf) Params added in v0.14.0 

func (t *TypeOf) Params() []expr.Expr

func (*TypeOf) String added in v0.14.0 

func (t *TypeOf) String() string

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