2018-04-17 15:16:08 -04:00
|
|
|
[[painless-general-syntax]]
|
|
|
|
|
=== General Syntax
|
2017-05-12 19:17:06 -04:00
|
|
|
|
|
|
|
|
[[control-flow]]
|
|
|
|
|
==== Control flow
|
|
|
|
|
|
|
|
|
|
Painless supports all of Java's https://docs.oracle.com/javase/tutorial/java/nutsandbolts/flow.html[
|
|
|
|
|
control flow statements] except the `switch` statement.
|
|
|
|
|
|
|
|
|
|
Painless also supports the `for in` syntax from Groovy:
|
|
|
|
|
|
|
|
|
|
[source,painless]
|
|
|
|
|
---------------------------------------------------------
|
|
|
|
|
for (item : list) {
|
|
|
|
|
...
|
|
|
|
|
}
|
|
|
|
|
---------------------------------------------------------
|
|
|
|
|
|
|
|
|
|
[[functions]]
|
|
|
|
|
==== Functions
|
|
|
|
|
|
|
|
|
|
You can declare functions at the beginning of a Painless script, for example:
|
|
|
|
|
|
|
|
|
|
[source,painless]
|
|
|
|
|
---------------------------------------------------------
|
|
|
|
|
boolean isNegative(def x) { x < 0 }
|
|
|
|
|
...
|
|
|
|
|
if (isNegative(someVar)) {
|
|
|
|
|
...
|
|
|
|
|
}
|
|
|
|
|
---------------------------------------------------------
|
|
|
|
|
|
|
|
|
|
[[lambda-expressions]]
|
|
|
|
|
==== Lambda expressions
|
|
|
|
|
Lambda expressions and method references work the same as in https://docs.oracle.com/javase/tutorial/java/javaOO/lambdaexpressions.html[Java].
|
|
|
|
|
|
|
|
|
|
[source,painless]
|
|
|
|
|
---------------------------------------------------------
|
|
|
|
|
list.removeIf(item -> item == 2);
|
|
|
|
|
list.removeIf((int item) -> item == 2);
|
|
|
|
|
list.removeIf((int item) -> { item == 2 });
|
|
|
|
|
list.sort((x, y) -> x - y);
|
|
|
|
|
list.sort(Integer::compare);
|
|
|
|
|
---------------------------------------------------------
|
|
|
|
|
|
|
|
|
|
You can make method references to functions within the script with `this`,
|
|
|
|
|
for example `list.sort(this::mycompare)`.
|
|
|
|
|
|
|
|
|
|
[[patterns]]
|
|
|
|
|
==== Patterns
|
|
|
|
|
|
|
|
|
|
Regular expression constants are directly supported. To ensure fast performance,
|
|
|
|
|
this is the only mechanism for creating patterns. Regular expressions
|
|
|
|
|
are always constants and compiled efficiently a single time.
|
|
|
|
|
|
|
|
|
|
[source,painless]
|
|
|
|
|
---------------------------------------------------------
|
|
|
|
|
Pattern p = /[aeiou]/
|
|
|
|
|
---------------------------------------------------------
|
|
|
|
|
|
|
|
|
|
[[pattern-flags]]
|
|
|
|
|
===== Pattern flags
|
|
|
|
|
|
|
|
|
|
You can define flags on patterns in Painless by adding characters after the
|
|
|
|
|
trailing `/` like `/foo/i` or `/foo \w #comment/iUx`. Painless exposes all of
|
|
|
|
|
the flags from Java's
|
|
|
|
|
https://docs.oracle.com/javase/8/docs/api/java/util/regex/Pattern.html[
|
|
|
|
|
Pattern class] using these characters:
|
|
|
|
|
|
|
|
|
|
[cols="<,<,<",options="header",]
|
|
|
|
|
|=======================================================================
|
|
|
|
|
| Character | Java Constant | Example
|
|
|
|
|
|`c` | CANON_EQ | `'å' ==~ /å/c` (open in hex editor to see)
|
|
|
|
|
|`i` | CASE_INSENSITIVE | `'A' ==~ /a/i`
|
|
|
|
|
|`l` | LITERAL | `'[a]' ==~ /[a]/l`
|
|
|
|
|
|`m` | MULTILINE | `'a\nb\nc' =~ /^b$/m`
|
|
|
|
|
|`s` | DOTALL (aka single line) | `'a\nb\nc' =~ /.b./s`
|
|
|
|
|
|`U` | UNICODE_CHARACTER_CLASS | `'Ɛ' ==~ /\\w/U`
|
|
|
|
|
|`u` | UNICODE_CASE | `'Ɛ' ==~ /ɛ/iu`
|
|
|
|
|
|`x` | COMMENTS (aka extended) | `'a' ==~ /a #comment/x`
|
|
|
|
|
|=======================================================================
|
