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Painless: Add flag support to regexes

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Painless: Add support for //m
Painless: Add support for //s
Painless: Add support for //i
Painless: Add support for //u
Painless: Add support for //U
Painless: Add support for //l
  This means "literal" and is exposed for completeness sake with
  the java api.
Painless: Add support for //c
  c enables Java's CANON_EQ (canonical equivalence) flag which makes
  unicode characters that are canonically equal match. Java's javadoc
  gives "a\u030A" being equal to "\u00E5". That is that the "a" code
  point followed by the "combining ring above" code point is equal to
  the "a with combining ring above" code point.
Update docs and add multi-flag test
Whitelist most of the Pattern class.
This commit is contained in:
Nik Everett 2016-06-16 11:07:09 -04:00
parent 3ebbbb3e37
commit b665d8a187
8 changed files with 289 additions and 174 deletions
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30
docs/reference/modules/scripting/painless.asciidoc
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@ -202,12 +202,15 @@ POST hockey/player/1/_update
// CONSOLE
[float]
[[modules-scripting-painless-regex]]
=== Regular expressions
Painless's native support for regular expressions has syntax constructs:
* `/pattern/`: Pattern literals create patterns. This is the only way to create
a pattern in painless.
a pattern in painless. The pattern inside the `/`s are just
http://docs.oracle.com/javase/8/docs/api/java/util/regex/Pattern.html[Java regular expressions].
See <<modules-scripting-painless-regex-flags>> for more.
* `=~`: The find operator return a `boolean`, `true` if a subsequence of the
text matches, `false` otherwise.
* `==~`: The match operator returns a `boolean`, `true` if the text matches,
@ -265,14 +268,35 @@ Note: all of the `_update_by_query` examples above could really do with a
because script queries aren't able to use the inverted index to limit the
documents that they have to check.
The pattern syntax is just
http://docs.oracle.com/javase/8/docs/api/java/util/regex/Pattern.html[Java regular expressions].
We intentionally don't allow scripts to call `Pattern.compile` to get a new
pattern on the fly because building a `Pattern` is (comparatively) slow.
Pattern literals (`/apattern/`) have fancy constant extraction so no matter
where they show up in the painless script they are built only when the script
is first used. It is fairly similar to how `String` literals work in Java.
[float]
[[modules-scripting-painless-regex-flags]]
==== Regular expression 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 the
flags from
https://docs.oracle.com/javase/7/docs/api/java/util/regex/Pattern.html[Java's 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`
|=======================================================================
[[painless-api]]
[float]