Documentation

System built-ins

Flux contains many preassigned values. These preassigned values are defined in the source files for the various built-in packages.

When a built-in value is not expressible in Flux, its value may be defined by the hosting environment. All such values must have a corresponding builtin statement to declare the existence and type of the built-in value.

BuiltinStatement = "builtin" identifier ":" TypeExpression .
TypeExpression   = MonoType ["where" Constraints] .

MonoType     = Tvar | BasicType | ArrayType | StreamType | VectorType | RecordType | FunctionType .
Tvar         = "A"  "Z" .
BasicType    = "int" | "uint" | "float" | "string" | "bool" | "time" | "duration" | "bytes" | "regexp" .
ArrayType    = "[" MonoType "]" .
StreamType   = "stream" "[" MonoType "]" .
VectorType   = "vector" "[" MonoType "]" .
RecordType   = ( "{" [RecordTypeProperties] "}" ) | ( "{" Tvar "with" RecordTypeProperties "}" ) .
FunctionType = "(" [FunctionTypeParameters] ")" "=>" MonoType .

RecordTypeProperties = RecordTypeProperty { "," RecordTypeProperty } .
RecordTypeProperty   = Label ":" MonoType .
Label = identifier | string_lit

FunctionTypeParameters = FunctionTypeParameter { "," FunctionTypeParameter } .
FunctionTypeParameter = [ "<-" | "?" ] identifier ":" MonoType .

Constraints = Constraint { "," Constraint } .
Constraint  = Tvar ":" Kinds .
Kinds       = identifier { "+" identifier } .
Example
builtin filter : (<-tables: stream[T], fn: (r: T) => bool) => stream[T]

Was this page helpful?

Thank you for your feedback!


The future of Flux

Flux is going into maintenance mode. You can continue using it as you currently are without any changes to your code.

Read more

New in InfluxDB 3.4

Key enhancements in InfluxDB 3.4 and the InfluxDB 3 Explorer 1.2.

See the Blog Post

InfluxDB 3.4 is now available for both Core and Enterprise, which introduces offline token generation for use in automated deployments and configurable license type selection that lets you bypass the interactive license prompt. InfluxDB 3 Explorer 1.2 is also available, which includes InfluxDB cache management and other new features.

For more information, check out: