Functions -
lang.stream
| close |
Closes a stream. |
| filter |
Selects the members from a stream for which a function returns true. |
| forEach |
Applies a function to each member of a stream. |
| iterator |
Returns an iterator over a stream. |
| map |
Applies a function to each member of a stream and returns a stream of the results. |
| next |
Returns the next element in the stream wrapped in a record or () if the stream ends. |
| reduce |
Combines the members of a stream using a combining function. |
close
(stream<Type ,ErrorType> stm)
returns ErrorType?Closes a stream. This releases any system resources being used by the stream.
Parameters
- stm stream<Type ,ErrorType>
-
the stream to close
-
Return Type
(ErrorType?) () if the close completed successfully, otherwise an error
filter
(stream<Type ,ErrorType> stm, function(Type) returns (boolean) func)
Selects the members from a stream for which a function returns true.
Parameters
- stm stream<Type ,ErrorType>
-
the stream
-
func
function(Type) returns (boolean) -
a predicate to apply to each member to test whether it should be selected
-
Return Type
(stream<Type ,ErrorType>) new stream only containing members of
stmfor whichfuncevaluates to true
forEach
(stream<Type ,ErrorType> stm, function(Type) returns (()) func)
Applies a function to each member of a stream. The Combining function is applied to each member of stream in order.
Parameters
- stm stream<Type ,ErrorType>
-
the stream
-
func
function(Type) returns (()) -
a function to apply to each member
-
Return Type
(ErrorType?) An error if iterating the stream encounters an error
iterator
(stream<Type ,ErrorType> stm)
returns object { public function next () returns ((record {| (any|error) value; |}|error?)?); }Returns an iterator over a stream.
Parameters
- stm stream<Type ,ErrorType>
-
the stream
-
Return Type
(object { public function next () returns ((record {| (any|error) value; |}|error?)?); }) a new iterator object that will iterate over the members of
stm.
map
(stream<Type ,ErrorType> stm, function(Type) returns (Type1) func)
Applies a function to each member of a stream and returns a stream of the results.
Parameters
- stm stream<Type ,ErrorType>
-
the stream
-
func
function(Type) returns (Type1) -
a function to apply to each member
-
Return Type
(stream<Type1 ,ErrorType>) new stream containing result of applying
functo each member ofstmin order
next
(stream<Type ,ErrorType> strm)
returns record {| (any|error) value; |} | ErrorType | ()Returns the next element in the stream wrapped in a record or () if the stream ends.
Parameters
- strm stream<Type ,ErrorType>
-
The stream
-
Return Type
(record {| (any|error) value; |} | ErrorType | ()) If the stream has elements, return the element wrapped in a record with single field called
value, otherwise returns ()
reduce
(stream<Type ,ErrorType> stm, function(Type1, Type) returns (Type1) func, Type1 initial)
Combines the members of a stream using a combining function. The combining function takes the combined value so far and a member of the stream, and returns a new combined value.
Parameters
- stm stream<Type ,ErrorType>
-
the stream
-
func
function(Type1, Type) returns (Type1) -
combining function
- initial Type1
-
initial value for the first argument of combining function
-
Return Type
(Type1 | ErrorType) result of combining the members of
stmusing the combining function