OpenSearch/docs/painless/painless-lang-spec/painless-comments.asciidoc

[[painless-comments]]
=== Comments

Use a comment to annotate or explain code within a script. Use the `//` token
anywhere on a line to specify a single-line comment. All characters from the
`//` token to the end of the line are ignored. Use an opening `/*` token and a
closing `*/` token to specify a multi-line comment. Multi-line comments can
start anywhere on a line, and all characters in between the `/*` token and `*/`
token are ignored. A comment is included anywhere within a script.

*Grammar*

[source,ANTLR4]
----
SINGLE_LINE_COMMENT: '//' .*? [\n\r];
MULTI_LINE_COMMENT: '/*' .*? '*/';
----

*Examples*

* Single-line comments.
+
[source,Painless]
----
// single-line comment

int value; // single-line comment
----
+
* Multi-line comments.
+
[source,Painless]
----
/* multi-
   line
   comment */

int value; /* multi-
              line
              comment */ value = 0;

int value; /* multi-line
              comment */

/* multi-line
   comment */ int value;

int value; /* multi-line
              comment */ value = 0;

int value; /* multi-line comment */ value = 0;
----