Add RegEx support using RE2 (rebased #665) #1039

Duologic · 2022-11-29T19:10:23Z

Rebased #665:

Introduces 5 new built-in methods to the stdlib:

regexFullMatch(pattern, str) -- Full match regex

regexPartialMatch(pattern, str) -- Partial match regex

regexQuoteMeta(str) -- Escape regex metachararacters

regexReplace(str, pattern, to) -- Replace single occurance using regex

regexGlobalReplace(str, pattern, to) -- Replace globally using regex

Since both regexFullMatch and regexPartialMatch can perform captures these functions return a "match" object upon match or null otherwise. For example:
$ ./jsonnet -e 'std.regexFullMatch("h(?P<mid>.*)o", "hello")'
{
   "captures": [
      "ell"
   ],
   "namedCaptures": {
      "mid": "ell"
   },
   "string": "hello"
}
Introduces a dependency on RE2 2019-06-01.
Builds tested using make, CMake and Bazel on Ubuntu 18.04.

I ran make and make test on Linux, not sure how to trigger TravisCI.

Introduces 5 new built-in methods to the stdlib: - `regexFullMatch(pattern, str)` -- Full match regex - `regexPartialMatch(pattern, str)` -- Partial match regex - `regexQuoteMeta(str)` -- Escape regex metachararacters - `regexReplace(str, pattern, to)` -- Replace single occurance using regex - `regexGlobalReplace(str, pattern, to)` -- Replace globally using regex Since both `regexFullMatch` and `regexPartialMatch` can perform captures these functions return a "match" object upon match or `null` otherwise. For example: ``` $ ./jsonnet -e 'std.regexFullMatch("h(?P<mid>.*)o", "hello")' { "captures": [ "ell" ], "namedCaptures": { "mid": "ell" }, "string": "hello" } ``` Introduces a dependency on RE2 2019-06-01. Builds tested using make, CMake and Bazel on Ubuntu 18.04.

Duologic · 2022-12-07T15:40:11Z

Anything else I should address? @sparkprime @sbarzowski

sbarzowski · 2023-01-17T00:09:34Z

Makefile

@@ -32,8 +32,7 @@ CXXFLAGS += -Iinclude -Ithird_party/md5 -Ithird_party/json -Ithird_party/rapidya
 CFLAGS ?= -g $(OPT) -Wall -Wextra -pedantic -std=c99 -fPIC
 CFLAGS += -Iinclude
 MAKEDEPENDFLAGS += -Iinclude -Ithird_party/md5 -Ithird_party/json -Ithird_party/rapidyaml/rapidyaml/src/ -Ithird_party/rapidyaml/rapidyaml/ext/c4core/src/
-LDFLAGS ?=
-
+LDFLAGS ?= -lre2


This is the most controversial part. Introducing a dependency here may break existing users. The fix is easy for them, so maybe not a very big deal. Going from 0 to some dependencies might still be problematic in some contexts, but it's probably worth it for regexps.

We definitely need to add a README section for dependencies, though. It would also be good to check that the Python package works as expected and maybe mention the dependencies in the description.

@sparkprime What do you think?

I'll look into that when I do the release. I presume it will break existing windows build processes but whoever uses that ought to be able to figure it out.

sbarzowski · 2023-01-17T00:11:54Z

test_suite/stdlib.jsonnet

+  }
+) &&
+
+std.assertEqual(std.regexQuoteMeta(@'1.5-2.0?'), '1\\.5\\-2\\.0\\?') &&


This quotes a string to be included in regexp verbatim, right?

I'm not sure if we want to offer this. Is there a very compelling use case? I would prefer to err on the side of having smaller API (easier to add than to remove).

Given that we are already locking into RE2, reducing the API surface isn't going to make it any easier to migrate to a different regex provider. In terms of implementation, it's a small wrapper around the underlying call.

In terms of usefulness, if you want to search for a computed something inside something else I suppose it would be invaluable.

I'm ok with it.

sbarzowski · 2023-01-17T00:12:48Z

Sorry it took so long to reply. Looks mostly good. Left some minor comments.

sparkprime · 2023-04-13T13:23:09Z

After I've done the current release (hopefully today) let's move forward on regex support in both impls for the next release.

sbarzowski · 2023-06-13T22:09:01Z

After I've done the current release (hopefully today) let's move forward on regex support in both impls for the next release.

Sounds good!

CertainLach

I think there should be an ability to process all matches, not only the first one, by returning matched indexes, or something like that?

CertainLach · 2023-06-15T17:27:41Z

test_suite/stdlib.jsonnet

+std.assertEqual(
+  std.regexPartialMatch(@'e(.*)o', 'hello'),
+  {
+    string: 'hello',


Shouldn't it be the 0th capture group, "ello"?

I don't think it's possible to do this with the underlying API. In fact I'm not sure why we repeat the given string back to the user at all. It is always just the string provided, which the caller already has.

If you want the behaviour of a "0th capture group" I suppose you can do @'(e(.*)o)' so it's not a loss of expressive power.

CertainLach · 2023-06-15T17:30:01Z

core/vm.cpp

+
+        int num_groups = re.NumberOfCapturingGroups();
+
+        std::vector<std::string> rcaptures(num_groups);


In case of optional group, h(.+)?o, should it be an empty string, or null?
std.regexFullMatch('h(.+)?o', 'ho').captures == ['']
std.regexFullMatch('h(.+)?o', 'ho').captures == [null]

If the underlying library returns an empty string then it's clearly "OK" to do that. Would we choose to differ? I'm not sure there's much point, because you have to do != null instead of != '' right? So it doesn't help the programmer to use null instead. On the other hand, it means there is a difference between the underlying library and the Jsonnet manifestation of it. That difference would have to be documented by us and remembered by everyone else.

You could also make the argument that the only reason the RE2 C++ API returns the empty string is because it is much harder to return a sentinel in that language. I wonder what the Go library does? @rohitjangid

Well, empty match is not the same as the optional group is not matched.
Howewer, looks like both C++ re2 and golang regex implementations don't care, and leave default type value for such matches, unlike Rust (https://docs.rs/regex/latest/regex/struct.Captures.html#method.get) and js regexps.

Upstream issue: google/jsonnet#1039

Duologic mentioned this pull request Nov 29, 2022

Add RegEx support using RE2 #665

Open

chore: use newer google/re2 version

e548dd9

Duologic marked this pull request as ready for review November 29, 2022 19:30

sbarzowski reviewed Jan 17, 2023

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CertainLach reviewed Jun 15, 2023

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CertainLach added a commit to CertainLach/jrsonnet that referenced this pull request Jun 15, 2023

feat: add std regex builtins

33ce087

Upstream issue: google/jsonnet#1039

CertainLach mentioned this pull request Jun 15, 2023

feat: add std regex builtins CertainLach/jrsonnet#119

Merged

sparkprime mentioned this pull request Jun 27, 2023

feat: implement std.match as standard function google/go-jsonnet#715

Open

CertainLach added a commit to CertainLach/jrsonnet that referenced this pull request Dec 10, 2023

feat: add std regex builtins

103c2a5

Upstream issue: google/jsonnet#1039

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Add RegEx support using RE2 (rebased #665) #1039

Add RegEx support using RE2 (rebased #665) #1039

Duologic commented Nov 29, 2022 •

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Duologic commented Dec 7, 2022

sbarzowski Jan 17, 2023

sparkprime Jul 5, 2023

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CertainLach Jun 15, 2023 •

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CertainLach Jul 12, 2023


		int num_groups = re.NumberOfCapturingGroups();

		std::vector<std::string> rcaptures(num_groups);

Add RegEx support using RE2 (rebased #665) #1039

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Duologic commented Nov 29, 2022 •

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