[
https://issues.apache.org/jira/browse/METRON-831?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15961860#comment-15961860
]
ASF GitHub Bot commented on METRON-831:
---------------------------------------
Github user jjmeyer0 commented on a diff in the pull request:
https://github.com/apache/incubator-metron/pull/517#discussion_r110520408
--- Diff: metron-platform/metron-common/README.md ---
@@ -466,6 +512,14 @@ The `!=` operator is the negation of the above.
* IANA Number
* Returns: The protocol name associated with the IANA number.
+### `REDUCE`
+ * Description: Reduces a list by a binary lambda expression. That is,
the expression takes two arguments. Usage example: `REDUCE( [ 1, 2, 3 ] , (x,
y) -> x + y)` would sum the input list, yielding `6`.
+ * Input:
+ * list - List of arguments.
+ * binary_operation - The lambda expression function to apply to reduce
the list. It is assumed that this takes two arguments, the first being the
running total and the second being an item from the list.
+ * initial_value - The initial value to use.
--- End diff --
This example is missing the `initial_value`.
> Add lambda expressions and rudimentary functional programming primitives to
> Stellar
> -----------------------------------------------------------------------------------
>
> Key: METRON-831
> URL: https://issues.apache.org/jira/browse/METRON-831
> Project: Metron
> Issue Type: Improvement
> Reporter: Casey Stella
>
> To enable use-cases where the user may want to do simple iteration, we can
> expose simple functional primitives such as:
> * MAP
> * REDUCE
> * FILTER
> To fully support this, we will need lambda expressions as arguments to these
> functions.
--
This message was sent by Atlassian JIRA
(v6.3.15#6346)
