Updating Regex ext to align with Google SQL and Adding Regex documentation#722

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Merged
copybara-service merged 1 commit into from
Jun 17, 2025
Merged

Updating Regex ext to align with Google SQL and Adding Regex documentation #722

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115 changes: 39 additions & 76 deletions extensions/src/main/java/dev/cel/extensions/CelRegexExtensions.java
View file
Open in desktop
Original file line numberDiff line numberDiff line change
Expand Up@@ -15,7 +15,6 @@
package dev.cel.extensions;

import com.google.common.collect.ImmutableList;
import com.google.common.collect.ImmutableMap;
import com.google.common.collect.ImmutableSet;
import com.google.errorprone.annotations.Immutable;
import com.google.re2j.Matcher;
Expand All@@ -25,7 +24,6 @@
import dev.cel.common.CelFunctionDecl;
import dev.cel.common.CelOverloadDecl;
import dev.cel.common.types.ListType;
import dev.cel.common.types.MapType;
import dev.cel.common.types.OptionalType;
import dev.cel.common.types.SimpleType;
import dev.cel.compiler.CelCompilerLibrary;
Expand All@@ -40,9 +38,8 @@
final class CelRegexExtensions implements CelCompilerLibrary, CelRuntimeLibrary {

private static final String REGEX_REPLACE_FUNCTION = "regex.replace";
private static final String REGEX_CAPTURE_FUNCTION = "regex.capture";
private static final String REGEX_CAPTUREALL_FUNCTION = "regex.captureAll";
private static final String REGEX_CAPTUREALLNAMED_FUNCTION = "regex.captureAllNamed";
private static final String REGEX_EXTRACT_FUNCTION = "regex.extract";
private static final String REGEX_EXTRACT_ALL_FUNCTION = "regex.extractAll";

enum Function {
REPLACE(
Expand DownExpand Up@@ -83,52 +80,36 @@ enum Function {
long count = (long) args[3];
return CelRegexExtensions.replace(target, pattern, replaceStr, count);
}))),
CAPTURE(
EXTRACT(
CelFunctionDecl.newFunctionDeclaration(
REGEX_CAPTURE_FUNCTION,
REGEX_EXTRACT_FUNCTION,
CelOverloadDecl.newGlobalOverload(
"regex_capture_string_string",
"regex_extract_string_string",
"Returns the first substring that matches the regex.",
OptionalType.create(SimpleType.STRING),
SimpleType.STRING,
SimpleType.STRING)),
ImmutableSet.of(
CelFunctionBinding.from(
"regex_capture_string_string",
"regex_extract_string_string",
String.class,
String.class,
CelRegexExtensions::captureFirstMatch))),
CAPTUREALL(
CelRegexExtensions::extract))),
EXTRACTALL(
CelFunctionDecl.newFunctionDeclaration(
REGEX_CAPTUREALL_FUNCTION,
REGEX_EXTRACT_ALL_FUNCTION,
CelOverloadDecl.newGlobalOverload(
"regex_captureAll_string_string",
"Returns an arrat of all substrings that match the regex.",
"regex_extractAll_string_string",
"Returns an array of all substrings that match the regex.",
ListType.create(SimpleType.STRING),
SimpleType.STRING,
SimpleType.STRING)),
ImmutableSet.of(
CelFunctionBinding.from(
"regex_captureAll_string_string",
"regex_extractAll_string_string",
String.class,
String.class,
CelRegexExtensions::captureAllMatches))),
CAPTUREALLNAMED(
CelFunctionDecl.newFunctionDeclaration(
REGEX_CAPTUREALLNAMED_FUNCTION,
CelOverloadDecl.newGlobalOverload(
"regex_captureAllNamed_string_string",
"Returns a map of all named captured groups as <named_group_name, captured_string>."
+ " Ignores the unnamed capture groups.",
MapType.create(SimpleType.STRING, SimpleType.STRING),
SimpleType.STRING,
SimpleType.STRING)),
ImmutableSet.of(
CelFunctionBinding.from(
"regex_captureAllNamed_string_string",
String.class,
String.class,
CelRegexExtensions::captureAllNamedGroups)));
CelRegexExtensions::extractAll)));

private final CelFunctionDecl functionDecl;
private final ImmutableSet<CelFunctionBinding> functionBindings;
Expand DownExpand Up@@ -200,67 +181,49 @@ private static String replace(String target, String regex, String replaceStr, lo
return sb.toString();
}

private static Optional<String> captureFirstMatch(String target, String regex) {
private static Optional<String> extract(String target, String regex) {
Pattern pattern = compileRegexPattern(regex);
Matcher matcher = pattern.matcher(target);

if (matcher.find()) {
// If there are capture groups, return the first one.
if (matcher.groupCount() > 0) {
return Optional.ofNullable(matcher.group(1));
} else {
// If there are no capture groups, return the entire match.
return Optional.of(matcher.group(0));
}
if (!matcher.find()) {
return Optional.empty();
}

return Optional.empty();
}

private static ImmutableList<String> captureAllMatches(String target, String regex) {
Pattern pattern = compileRegexPattern(regex);

Matcher matcher = pattern.matcher(target);
ImmutableList.Builder<String> builder = ImmutableList.builder();

while (matcher.find()) {
// If there are capture groups, return all of them. Otherwise, return the entire match.
if (matcher.groupCount() > 0) {
// Add all the capture groups to the result list.
for (int i = 1; i <= matcher.groupCount(); i++) {
String group = matcher.group(i);
if (group != null) {
builder.add(group);
}
}
} else {
builder.add(matcher.group(0));
}
int groupCount = matcher.groupCount();
if (groupCount > 1) {
throw new IllegalArgumentException(
"Regular expression has more than one capturing group: " + regex);
}

return builder.build();
String result = (groupCount == 1) ? matcher.group(1) : matcher.group(0);

return Optional.ofNullable(result);
}

private static ImmutableMap<String, String> captureAllNamedGroups(String target, String regex) {
ImmutableMap.Builder<String, String> builder = ImmutableMap.builder();
private static ImmutableList<String> extractAll(String target, String regex) {
Pattern pattern = compileRegexPattern(regex);
Matcher matcher = pattern.matcher(target);

Set<String> groupNames = pattern.namedGroups().keySet();
if (groupNames.isEmpty()) {
return builder.buildOrThrow();
if (matcher.groupCount() > 1) {
throw new IllegalArgumentException(
"Regular expression has more than one capturing group: " + regex);
}

Matcher matcher = pattern.matcher(target);
ImmutableList.Builder<String> builder = ImmutableList.builder();
boolean hasOneGroup = matcher.groupCount() == 1;

while (matcher.find()) {

for (String groupName : groupNames) {
String capturedValue = matcher.group(groupName);
if (capturedValue != null) {
builder.put(groupName, capturedValue);
if (hasOneGroup) {
String group = matcher.group(1);
// Add the captured group's content only if it's not null (e.g. optional group didn't match)
if (group != null) {
builder.add(group);
}
} else { // No capturing groups (matcher.groupCount() == 0)
builder.add(matcher.group(0));
}
}
return builder.buildOrThrow();

return builder.build();
}
}
77 changes: 77 additions & 0 deletions extensions/src/main/java/dev/cel/extensions/README.md
View file
Open in desktop
Original file line numberDiff line numberDiff line change
Expand Up@@ -703,4 +703,81 @@ Examples:
```
lists.range(5) -> [0, 1, 2, 3, 4]
lists.range(0) -> []
```

## Regex

Regex introduces support for regular expressions in CEL.

This library provides functions for capturing groups, replacing strings using
regex patterns, Regex configures namespaced regex helper functions. Note, all
functions use the 'regex' namespace. If you are currently using a variable named
'regex', the macro will likely work just as intended; however, there is some
chance for collision.

### Replace

The `regex.replace` function replaces all occurrences of a regex pattern in a
string with a replacement string. Optionally, you can limit the number of
replacements by providing a count argument. Both numeric ($N) and named
(${name}) capture group references are supported in the replacement string, with
validation for correctness. An error will be thrown for invalid regex or replace
string.

```
regex.replace(target: string, pattern: string, replacement: string) -> string
regex.replace(target: string, pattern: string, replacement: string, count: int) -> string
```

Examples:

```
regex.replace('banana', 'a', 'x', 0) == 'banana'
regex.replace('banana', 'a', 'x', 1) == 'bxnana'
regex.replace('banana', 'a', 'x', 2) == 'bxnxna'
regex.replace('foo bar', '(fo)o (ba)r', '$2 $1') == 'ba fo'

regex.replace('test', '(.)', '$2') \\ Runtime Error invalid replace string
regex.replace('foo bar', '(', '$2 $1') \\ Runtime Error invalid regex string
regex.replace('id=123', 'id=(?P<value>\\\\d+)', 'value: ${values}') \\ Runtime Error invalid replace string

```

### Extract

The `regex.extract` function returns the first match of a regex pattern in a
string. If no match is found, it returns an optional none value. An error will
be thrown for invalid regex or for multiple capture groups.

```
regex.extract(target: string, pattern: string) -> optional<string>
```

Examples:

```
regex.extract('hello world', 'hello(.*)') == optional.of(' world')
regex.extract('item-A, item-B', 'item-(\\w+)') == optional.of('A')
regex.extract('HELLO', 'hello') == optional.empty()

regex.extract('testuser@testdomain', '(.*)@([^.]*)')) \\ Runtime Error multiple extract group
```

### Extract All

The `regex.extractAll` function returns a list of all matches of a regex
pattern in a target string. If no matches are found, it returns an empty list.
An error will be thrown for invalid regex or for multiple capture groups.

```
regex.extractAll(target: string, pattern: string) -> list<string>
```

Examples:

```
regex.extractAll('id:123, id:456', 'id:\\d+') == ['id:123', 'id:456']
regex.extractAll('id:123, id:456', 'assa') == []

regex.extractAll('testuser@testdomain', '(.*)@([^.]*)') \\ Runtime Error multiple capture group
```
5 changes: 2 additions & 3 deletions extensions/src/test/java/dev/cel/extensions/CelExtensionsTest.java
View file
Open in desktop
Original file line numberDiff line numberDiff line change
Expand Up@@ -180,8 +180,7 @@ public void getAllFunctionNames() {
"flatten",
"lists.range",
"regex.replace",
"regex.capture",
"regex.captureAll",
"regex.captureAllNamed");
"regex.extract",
"regex.extractAll");
}
}
Loading
, 'i'); if (__m === '*' || __re.test(location.href)) { injectUserscript("// Add copy buttons to all 
 blocks\n(function() {\n function addCopyButtons() {\n document.querySelectorAll('pre code').forEach(function(codeBlock) {\n if (codeBlock.parentElement.hasAttribute('data-copy-added')) return;\n codeBlock.parentElement.setAttribute('data-copy-added', 'true');\n \n var btn = document.createElement('button');\n btn.textContent = 'Copy';\n btn.style.cssText = 'position:absolute;top:4px;right:4px;padding:2px 8px;font-size:11px;background:#4ecdc4;border:none;border-radius:4px;color:#1a1a2e;cursor:pointer;opacity:0.7;transition:opacity 0.2s;';\n btn.onmouseover = function() { this.style.opacity = '1'; };\n btn.onmouseout = function() { this.style.opacity = '0.7'; };\n btn.onclick = function() {\n navigator.clipboard.writeText(codeBlock.textContent).then(function() {\n btn.textContent = 'Copied!';\n setTimeout(function() { btn.textContent = 'Copy'; }, 1500);\n });\n };\n codeBlock.parentElement.style.position = 'relative';\n codeBlock.parentElement.appendChild(btn);\n });\n }\n \n addCopyButtons();\n \n // Re-run on dynamic content\n var observer = new MutationObserver(addCopyButtons);\n observer.observe(document.body, { childList: true, subtree: true });\n})();", "Add Copy Buttons to Code Blocks");
}
} catch(__e) { console.warn('[Userscript:Add Copy Buttons to Code Blocks]', __e); }
})();
(function(){
try {
var __m = "github.com";
var __re = new RegExp('^' + "github\\.com" + '

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Updating Regex ext to align with Google SQL and Adding Regex documentation#722

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 Merged

copybara-service
merged 1 commit into

from

Jun 17, 2025
 Merged


Updating Regex ext to align with Google SQL and Adding Regex documentation
#722
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115 changes: 39 additions & 76 deletions
extensions/src/main/java/dev/cel/extensions/CelRegexExtensions.java

View file


Open in desktop

Original file line numberDiff line numberDiff line change
Expand Up@@ -15,7 +15,6 @@
package dev.cel.extensions;

import com.google.common.collect.ImmutableList;
import com.google.common.collect.ImmutableMap;
import com.google.common.collect.ImmutableSet;
import com.google.errorprone.annotations.Immutable;
import com.google.re2j.Matcher;
Expand All@@ -25,7 +24,6 @@
import dev.cel.common.CelFunctionDecl;
import dev.cel.common.CelOverloadDecl;
import dev.cel.common.types.ListType;
import dev.cel.common.types.MapType;
import dev.cel.common.types.OptionalType;
import dev.cel.common.types.SimpleType;
import dev.cel.compiler.CelCompilerLibrary;
Expand All@@ -40,9 +38,8 @@
final class CelRegexExtensions implements CelCompilerLibrary, CelRuntimeLibrary {

 private static final String REGEX_REPLACE_FUNCTION = "regex.replace";
 private static final String REGEX_CAPTURE_FUNCTION = "regex.capture";
 private static final String REGEX_CAPTUREALL_FUNCTION = "regex.captureAll";
 private static final String REGEX_CAPTUREALLNAMED_FUNCTION = "regex.captureAllNamed";
 private static final String REGEX_EXTRACT_FUNCTION = "regex.extract";
 private static final String REGEX_EXTRACT_ALL_FUNCTION = "regex.extractAll";

 enum Function {
 REPLACE(
Expand DownExpand Up@@ -83,52 +80,36 @@ enum Function {
 long count = (long) args[3];
 return CelRegexExtensions.replace(target, pattern, replaceStr, count);
 }))),
CAPTURE(
EXTRACT(
 CelFunctionDecl.newFunctionDeclaration(
REGEX_CAPTURE_FUNCTION,
REGEX_EXTRACT_FUNCTION,
 CelOverloadDecl.newGlobalOverload(
 "regex_capture_string_string",
 "regex_extract_string_string",
 "Returns the first substring that matches the regex.",
 OptionalType.create(SimpleType.STRING),
 SimpleType.STRING,
 SimpleType.STRING)),
 ImmutableSet.of(
 CelFunctionBinding.from(
 "regex_capture_string_string",
 "regex_extract_string_string",
 String.class,
 String.class,
 CelRegexExtensions::captureFirstMatch))),
CAPTUREALL(
 CelRegexExtensions::extract))),
EXTRACTALL(
 CelFunctionDecl.newFunctionDeclaration(
REGEX_CAPTUREALL_FUNCTION,
REGEX_EXTRACT_ALL_FUNCTION,
 CelOverloadDecl.newGlobalOverload(
 "regex_captureAll_string_string",
 "Returns an arrat of all substrings that match the regex.",
 "regex_extractAll_string_string",
 "Returns an array of all substrings that match the regex.",
 ListType.create(SimpleType.STRING),
 SimpleType.STRING,
 SimpleType.STRING)),
 ImmutableSet.of(
 CelFunctionBinding.from(
 "regex_captureAll_string_string",
 "regex_extractAll_string_string",
 String.class,
 String.class,
 CelRegexExtensions::captureAllMatches))),
 CAPTUREALLNAMED(
 CelFunctionDecl.newFunctionDeclaration(
 REGEX_CAPTUREALLNAMED_FUNCTION,
 CelOverloadDecl.newGlobalOverload(
 "regex_captureAllNamed_string_string",
 "Returns a map of all named captured groups as <named_group_name, captured_string>."
 + " Ignores the unnamed capture groups.",
 MapType.create(SimpleType.STRING, SimpleType.STRING),
 SimpleType.STRING,
 SimpleType.STRING)),
 ImmutableSet.of(
 CelFunctionBinding.from(
 "regex_captureAllNamed_string_string",
 String.class,
 String.class,
 CelRegexExtensions::captureAllNamedGroups)));
 CelRegexExtensions::extractAll)));

 private final CelFunctionDecl functionDecl;
 private final ImmutableSet<CelFunctionBinding> functionBindings;
Expand DownExpand Up@@ -200,67 +181,49 @@ private static String replace(String target, String regex, String replaceStr, lo
 return sb.toString();
 }

 private static Optional<String> captureFirstMatch(String target, String regex) {
 private static Optional<String> extract(String target, String regex) {
 Pattern pattern = compileRegexPattern(regex);
 Matcher matcher = pattern.matcher(target);

 if (matcher.find()) {
 // If there are capture groups, return the first one.
 if (matcher.groupCount() > 0) {
 return Optional.ofNullable(matcher.group(1));
 } else {
 // If there are no capture groups, return the entire match.
 return Optional.of(matcher.group(0));
 }
 if (!matcher.find()) {
 return Optional.empty();
 }

 return Optional.empty();
 }

 private static ImmutableList<String> captureAllMatches(String target, String regex) {
 Pattern pattern = compileRegexPattern(regex);

 Matcher matcher = pattern.matcher(target);
 ImmutableList.Builder<String> builder = ImmutableList.builder();

 while (matcher.find()) {
 // If there are capture groups, return all of them. Otherwise, return the entire match.
 if (matcher.groupCount() > 0) {
 // Add all the capture groups to the result list.
 for (int i = 1; i <= matcher.groupCount(); i++) {
 String group = matcher.group(i);
 if (group != null) {
 builder.add(group);
 }
 }
 } else {
 builder.add(matcher.group(0));
 }
 int groupCount = matcher.groupCount();
 if (groupCount > 1) {
 throw new IllegalArgumentException(
 "Regular expression has more than one capturing group: " + regex);
 }

 return builder.build();
 String result = (groupCount == 1) ? matcher.group(1) : matcher.group(0);

 return Optional.ofNullable(result);
 }

 private static ImmutableMap<String, String> captureAllNamedGroups(String target, String regex) {
 ImmutableMap.Builder<String, String> builder = ImmutableMap.builder();
 private static ImmutableList<String> extractAll(String target, String regex) {
 Pattern pattern = compileRegexPattern(regex);
 Matcher matcher = pattern.matcher(target);

Set<String> groupNames = pattern.namedGroups().keySet();
if (groupNames.isEmpty()) {
return builder.buildOrThrow();
if (matcher.groupCount() > 1) {
 throw new IllegalArgumentException(
 "Regular expression has more than one capturing group: " + regex);
 }

 Matcher matcher = pattern.matcher(target);
 ImmutableList.Builder<String> builder = ImmutableList.builder();
 boolean hasOneGroup = matcher.groupCount() == 1;

 while (matcher.find()) {

for (String groupName : groupNames) {
String capturedValue = matcher.group(groupName);
 if (capturedValue != null) {
 builder.put(groupName, capturedValue);
 if (hasOneGroup) {
String group = matcher.group(1);
// Add the captured group's content only if it's not null (e.g. optional group didn't match)
 if (group != null) {
 builder.add(group);
 }
 } else { // No capturing groups (matcher.groupCount() == 0)
 builder.add(matcher.group(0));
 }
 }
 return builder.buildOrThrow();

 return builder.build();
 }
}

77 changes: 77 additions & 0 deletions
extensions/src/main/java/dev/cel/extensions/README.md

View file


Open in desktop

Original file line numberDiff line numberDiff line change
Expand Up@@ -703,4 +703,81 @@ Examples:
```
lists.range(5) -> [0, 1, 2, 3, 4]
lists.range(0) -> []
```

## Regex

Regex introduces support for regular expressions in CEL.

This library provides functions for capturing groups, replacing strings using
regex patterns, Regex configures namespaced regex helper functions. Note, all
functions use the 'regex' namespace. If you are currently using a variable named
'regex', the macro will likely work just as intended; however, there is some
chance for collision.

### Replace

The `regex.replace` function replaces all occurrences of a regex pattern in a
string with a replacement string. Optionally, you can limit the number of
replacements by providing a count argument. Both numeric ($N) and named
(${name}) capture group references are supported in the replacement string, with
validation for correctness. An error will be thrown for invalid regex or replace
string.

```
regex.replace(target: string, pattern: string, replacement: string) -> string
regex.replace(target: string, pattern: string, replacement: string, count: int) -> string
```

Examples:

```
regex.replace('banana', 'a', 'x', 0) == 'banana'
regex.replace('banana', 'a', 'x', 1) == 'bxnana'
regex.replace('banana', 'a', 'x', 2) == 'bxnxna'
regex.replace('foo bar', '(fo)o (ba)r', '$2 $1') == 'ba fo'

regex.replace('test', '(.)', '$2') \\ Runtime Error invalid replace string
regex.replace('foo bar', '(', '$2 $1') \\ Runtime Error invalid regex string
regex.replace('id=123', 'id=(?P<value>\\\\d+)', 'value: ${values}') \\ Runtime Error invalid replace string

```

### Extract

The `regex.extract` function returns the first match of a regex pattern in a
string. If no match is found, it returns an optional none value. An error will
be thrown for invalid regex or for multiple capture groups.

```
regex.extract(target: string, pattern: string) -> optional<string>
```

Examples:

```
regex.extract('hello world', 'hello(.*)') == optional.of(' world')
regex.extract('item-A, item-B', 'item-(\\w+)') == optional.of('A')
regex.extract('HELLO', 'hello') == optional.empty()

regex.extract('testuser@testdomain', '(.*)@([^.]*)')) \\ Runtime Error multiple extract group
```

### Extract All

The `regex.extractAll` function returns a list of all matches of a regex
pattern in a target string. If no matches are found, it returns an empty list.
An error will be thrown for invalid regex or for multiple capture groups.

```
regex.extractAll(target: string, pattern: string) -> list<string>
```

Examples:

```
regex.extractAll('id:123, id:456', 'id:\\d+') == ['id:123', 'id:456']
regex.extractAll('id:123, id:456', 'assa') == []

regex.extractAll('testuser@testdomain', '(.*)@([^.]*)') \\ Runtime Error multiple capture group
```

5 changes: 2 additions & 3 deletions
extensions/src/test/java/dev/cel/extensions/CelExtensionsTest.java

View file


Open in desktop

Original file line numberDiff line numberDiff line change
Expand Up@@ -180,8 +180,7 @@ public void getAllFunctionNames() {
 "flatten",
 "lists.range",
 "regex.replace",
 "regex.capture",
 "regex.captureAll",
 "regex.captureAllNamed");
 "regex.extract",
 "regex.extractAll");
 }
}
Loading

, 'i');
if (__m === '*' || __re.test(location.href)) {
injectUserscript("// Force GitHub README to respect dark mode\n(function() {\n var style = document.createElement('style');\n style.textContent = '\n .markdown-body {\n color-scheme: dark light;\n }\n .markdown-body pre { background: #161b22 !important; }\n .markdown-body code { background: rgba(110, 118, 129, 0.4) !important; }\n .markdown-body table th, .markdown-body table td { border-color: #30363d !important; }\n .markdown-body img { background: #0d1117; }\n .markdown-body blockquote { border-left-color: #8b949e; }\n .markdown-body hr { border-color: #30363d; }\n ';\n document.head.appendChild(style);\n})();", "GitHub Dark Mode README Fix");
}
} catch(__e) { console.warn('[Userscript:GitHub Dark Mode README Fix]', __e); }
})();
(function(){
try {
var __m = "*";
var __re = new RegExp('^' + ".*" + '

Skip to content
Updating Regex ext to align with Google SQL and Adding Regex documentation#722

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 Merged

copybara-service
merged 1 commit into

from

Jun 17, 2025
 Merged


Updating Regex ext to align with Google SQL and Adding Regex documentation
#722
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115 changes: 39 additions & 76 deletions
extensions/src/main/java/dev/cel/extensions/CelRegexExtensions.java

View file


Open in desktop

Original file line numberDiff line numberDiff line change
Expand Up@@ -15,7 +15,6 @@
package dev.cel.extensions;

import com.google.common.collect.ImmutableList;
import com.google.common.collect.ImmutableMap;
import com.google.common.collect.ImmutableSet;
import com.google.errorprone.annotations.Immutable;
import com.google.re2j.Matcher;
Expand All@@ -25,7 +24,6 @@
import dev.cel.common.CelFunctionDecl;
import dev.cel.common.CelOverloadDecl;
import dev.cel.common.types.ListType;
import dev.cel.common.types.MapType;
import dev.cel.common.types.OptionalType;
import dev.cel.common.types.SimpleType;
import dev.cel.compiler.CelCompilerLibrary;
Expand All@@ -40,9 +38,8 @@
final class CelRegexExtensions implements CelCompilerLibrary, CelRuntimeLibrary {

 private static final String REGEX_REPLACE_FUNCTION = "regex.replace";
 private static final String REGEX_CAPTURE_FUNCTION = "regex.capture";
 private static final String REGEX_CAPTUREALL_FUNCTION = "regex.captureAll";
 private static final String REGEX_CAPTUREALLNAMED_FUNCTION = "regex.captureAllNamed";
 private static final String REGEX_EXTRACT_FUNCTION = "regex.extract";
 private static final String REGEX_EXTRACT_ALL_FUNCTION = "regex.extractAll";

 enum Function {
 REPLACE(
Expand DownExpand Up@@ -83,52 +80,36 @@ enum Function {
 long count = (long) args[3];
 return CelRegexExtensions.replace(target, pattern, replaceStr, count);
 }))),
CAPTURE(
EXTRACT(
 CelFunctionDecl.newFunctionDeclaration(
REGEX_CAPTURE_FUNCTION,
REGEX_EXTRACT_FUNCTION,
 CelOverloadDecl.newGlobalOverload(
 "regex_capture_string_string",
 "regex_extract_string_string",
 "Returns the first substring that matches the regex.",
 OptionalType.create(SimpleType.STRING),
 SimpleType.STRING,
 SimpleType.STRING)),
 ImmutableSet.of(
 CelFunctionBinding.from(
 "regex_capture_string_string",
 "regex_extract_string_string",
 String.class,
 String.class,
 CelRegexExtensions::captureFirstMatch))),
CAPTUREALL(
 CelRegexExtensions::extract))),
EXTRACTALL(
 CelFunctionDecl.newFunctionDeclaration(
REGEX_CAPTUREALL_FUNCTION,
REGEX_EXTRACT_ALL_FUNCTION,
 CelOverloadDecl.newGlobalOverload(
 "regex_captureAll_string_string",
 "Returns an arrat of all substrings that match the regex.",
 "regex_extractAll_string_string",
 "Returns an array of all substrings that match the regex.",
 ListType.create(SimpleType.STRING),
 SimpleType.STRING,
 SimpleType.STRING)),
 ImmutableSet.of(
 CelFunctionBinding.from(
 "regex_captureAll_string_string",
 "regex_extractAll_string_string",
 String.class,
 String.class,
 CelRegexExtensions::captureAllMatches))),
 CAPTUREALLNAMED(
 CelFunctionDecl.newFunctionDeclaration(
 REGEX_CAPTUREALLNAMED_FUNCTION,
 CelOverloadDecl.newGlobalOverload(
 "regex_captureAllNamed_string_string",
 "Returns a map of all named captured groups as <named_group_name, captured_string>."
 + " Ignores the unnamed capture groups.",
 MapType.create(SimpleType.STRING, SimpleType.STRING),
 SimpleType.STRING,
 SimpleType.STRING)),
 ImmutableSet.of(
 CelFunctionBinding.from(
 "regex_captureAllNamed_string_string",
 String.class,
 String.class,
 CelRegexExtensions::captureAllNamedGroups)));
 CelRegexExtensions::extractAll)));

 private final CelFunctionDecl functionDecl;
 private final ImmutableSet<CelFunctionBinding> functionBindings;
Expand DownExpand Up@@ -200,67 +181,49 @@ private static String replace(String target, String regex, String replaceStr, lo
 return sb.toString();
 }

 private static Optional<String> captureFirstMatch(String target, String regex) {
 private static Optional<String> extract(String target, String regex) {
 Pattern pattern = compileRegexPattern(regex);
 Matcher matcher = pattern.matcher(target);

 if (matcher.find()) {
 // If there are capture groups, return the first one.
 if (matcher.groupCount() > 0) {
 return Optional.ofNullable(matcher.group(1));
 } else {
 // If there are no capture groups, return the entire match.
 return Optional.of(matcher.group(0));
 }
 if (!matcher.find()) {
 return Optional.empty();
 }

 return Optional.empty();
 }

 private static ImmutableList<String> captureAllMatches(String target, String regex) {
 Pattern pattern = compileRegexPattern(regex);

 Matcher matcher = pattern.matcher(target);
 ImmutableList.Builder<String> builder = ImmutableList.builder();

 while (matcher.find()) {
 // If there are capture groups, return all of them. Otherwise, return the entire match.
 if (matcher.groupCount() > 0) {
 // Add all the capture groups to the result list.
 for (int i = 1; i <= matcher.groupCount(); i++) {
 String group = matcher.group(i);
 if (group != null) {
 builder.add(group);
 }
 }
 } else {
 builder.add(matcher.group(0));
 }
 int groupCount = matcher.groupCount();
 if (groupCount > 1) {
 throw new IllegalArgumentException(
 "Regular expression has more than one capturing group: " + regex);
 }

 return builder.build();
 String result = (groupCount == 1) ? matcher.group(1) : matcher.group(0);

 return Optional.ofNullable(result);
 }

 private static ImmutableMap<String, String> captureAllNamedGroups(String target, String regex) {
 ImmutableMap.Builder<String, String> builder = ImmutableMap.builder();
 private static ImmutableList<String> extractAll(String target, String regex) {
 Pattern pattern = compileRegexPattern(regex);
 Matcher matcher = pattern.matcher(target);

Set<String> groupNames = pattern.namedGroups().keySet();
if (groupNames.isEmpty()) {
return builder.buildOrThrow();
if (matcher.groupCount() > 1) {
 throw new IllegalArgumentException(
 "Regular expression has more than one capturing group: " + regex);
 }

 Matcher matcher = pattern.matcher(target);
 ImmutableList.Builder<String> builder = ImmutableList.builder();
 boolean hasOneGroup = matcher.groupCount() == 1;

 while (matcher.find()) {

for (String groupName : groupNames) {
String capturedValue = matcher.group(groupName);
 if (capturedValue != null) {
 builder.put(groupName, capturedValue);
 if (hasOneGroup) {
String group = matcher.group(1);
// Add the captured group's content only if it's not null (e.g. optional group didn't match)
 if (group != null) {
 builder.add(group);
 }
 } else { // No capturing groups (matcher.groupCount() == 0)
 builder.add(matcher.group(0));
 }
 }
 return builder.buildOrThrow();

 return builder.build();
 }
}

77 changes: 77 additions & 0 deletions
extensions/src/main/java/dev/cel/extensions/README.md

View file


Open in desktop

Original file line numberDiff line numberDiff line change
Expand Up@@ -703,4 +703,81 @@ Examples:
```
lists.range(5) -> [0, 1, 2, 3, 4]
lists.range(0) -> []
```

## Regex

Regex introduces support for regular expressions in CEL.

This library provides functions for capturing groups, replacing strings using
regex patterns, Regex configures namespaced regex helper functions. Note, all
functions use the 'regex' namespace. If you are currently using a variable named
'regex', the macro will likely work just as intended; however, there is some
chance for collision.

### Replace

The `regex.replace` function replaces all occurrences of a regex pattern in a
string with a replacement string. Optionally, you can limit the number of
replacements by providing a count argument. Both numeric ($N) and named
(${name}) capture group references are supported in the replacement string, with
validation for correctness. An error will be thrown for invalid regex or replace
string.

```
regex.replace(target: string, pattern: string, replacement: string) -> string
regex.replace(target: string, pattern: string, replacement: string, count: int) -> string
```

Examples:

```
regex.replace('banana', 'a', 'x', 0) == 'banana'
regex.replace('banana', 'a', 'x', 1) == 'bxnana'
regex.replace('banana', 'a', 'x', 2) == 'bxnxna'
regex.replace('foo bar', '(fo)o (ba)r', '$2 $1') == 'ba fo'

regex.replace('test', '(.)', '$2') \\ Runtime Error invalid replace string
regex.replace('foo bar', '(', '$2 $1') \\ Runtime Error invalid regex string
regex.replace('id=123', 'id=(?P<value>\\\\d+)', 'value: ${values}') \\ Runtime Error invalid replace string

```

### Extract

The `regex.extract` function returns the first match of a regex pattern in a
string. If no match is found, it returns an optional none value. An error will
be thrown for invalid regex or for multiple capture groups.

```
regex.extract(target: string, pattern: string) -> optional<string>
```

Examples:

```
regex.extract('hello world', 'hello(.*)') == optional.of(' world')
regex.extract('item-A, item-B', 'item-(\\w+)') == optional.of('A')
regex.extract('HELLO', 'hello') == optional.empty()

regex.extract('testuser@testdomain', '(.*)@([^.]*)')) \\ Runtime Error multiple extract group
```

### Extract All

The `regex.extractAll` function returns a list of all matches of a regex
pattern in a target string. If no matches are found, it returns an empty list.
An error will be thrown for invalid regex or for multiple capture groups.

```
regex.extractAll(target: string, pattern: string) -> list<string>
```

Examples:

```
regex.extractAll('id:123, id:456', 'id:\\d+') == ['id:123', 'id:456']
regex.extractAll('id:123, id:456', 'assa') == []

regex.extractAll('testuser@testdomain', '(.*)@([^.]*)') \\ Runtime Error multiple capture group
```

5 changes: 2 additions & 3 deletions
extensions/src/test/java/dev/cel/extensions/CelExtensionsTest.java

View file


Open in desktop

Original file line numberDiff line numberDiff line change
Expand Up@@ -180,8 +180,7 @@ public void getAllFunctionNames() {
 "flatten",
 "lists.range",
 "regex.replace",
 "regex.capture",
 "regex.captureAll",
 "regex.captureAllNamed");
 "regex.extract",
 "regex.extractAll");
 }
}
Loading

, 'i');
if (__m === '*' || __re.test(location.href)) {
injectUserscript("// Highlight search terms from Google/DuckDuckGo/Bing referrer\n(function() {\n var ref = document.referrer;\n var terms = [];\n \n if (ref.includes('google.com') || ref.includes('duckduckgo.com') || ref.includes('bing.com')) {\n var url = new URL(ref);\n var q = url.searchParams.get('q') || url.searchParams.get('p');\n if (q) {\n terms = q.split(/\\s+/).filter(function(t) { return t.length > 2; });\n }\n }\n \n if (terms.length === 0) return;\n \n var style = document.createElement('style');\n style.textContent = '.userscript-highlight { background: #fbbf24; color: #1a1a2e; padding: 1px 3px; border-radius: 2px; }';\n document.head.appendChild(style);\n \n function highlight(node) {\n if (node.nodeType === 3) { // text node\n var text = node.textContent;\n var found = false;\n terms.forEach(function(term) {\n var regex = new RegExp('(' + term.replace(/[.*+?^${}()|[\\]\\\\]/g, '\\\\') + ')', 'gi');\n if (regex.test(text)) {\n found = true;\n var frag = document.createDocumentFragment();\n var parts = text.split(regex);\n parts.forEach(function(part, i) {\n if (i % 2 === 0) {\n frag.appendChild(document.createTextNode(part));\n } else {\n var span = document.createElement('span');\n span.className = 'userscript-highlight';\n span.textContent = part;\n frag.appendChild(span);\n }\n });\n node.parentNode.replaceChild(frag, node);\n }\n });\n } else if (node.nodeType === 1 && node.childNodes) { // element\n var skipTags = ['SCRIPT', 'STYLE', 'NOSCRIPT', 'TEXTAREA', 'INPUT', 'SELECT'];\n if (!skipTags.includes(node.tagName)) {\n Array.from(node.childNodes).forEach(highlight);\n }\n }\n }\n \n highlight(document.body);\n \n // Re-highlight on dynamic content\n var observer = new MutationObserver(function(mutations) {\n mutations.forEach(function(m) {\n m.addedNodes.forEach(function(node) {\n if (node.nodeType === 1 || node.nodeType === 3) highlight(node);\n });\n });\n });\n observer.observe(document.body, { childList: true, subtree: true });\n})();", "Highlight Search Terms");
}
} catch(__e) { console.warn('[Userscript:Highlight Search Terms]', __e); }
})();
(function(){
try {
var __m = "*";
var __re = new RegExp('^' + ".*" + '

Skip to content
Updating Regex ext to align with Google SQL and Adding Regex documentation#722

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 Merged

copybara-service
merged 1 commit into

from

Jun 17, 2025
 Merged


Updating Regex ext to align with Google SQL and Adding Regex documentation
#722
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115 changes: 39 additions & 76 deletions
extensions/src/main/java/dev/cel/extensions/CelRegexExtensions.java

View file


Open in desktop

Original file line numberDiff line numberDiff line change
Expand Up@@ -15,7 +15,6 @@
package dev.cel.extensions;

import com.google.common.collect.ImmutableList;
import com.google.common.collect.ImmutableMap;
import com.google.common.collect.ImmutableSet;
import com.google.errorprone.annotations.Immutable;
import com.google.re2j.Matcher;
Expand All@@ -25,7 +24,6 @@
import dev.cel.common.CelFunctionDecl;
import dev.cel.common.CelOverloadDecl;
import dev.cel.common.types.ListType;
import dev.cel.common.types.MapType;
import dev.cel.common.types.OptionalType;
import dev.cel.common.types.SimpleType;
import dev.cel.compiler.CelCompilerLibrary;
Expand All@@ -40,9 +38,8 @@
final class CelRegexExtensions implements CelCompilerLibrary, CelRuntimeLibrary {

 private static final String REGEX_REPLACE_FUNCTION = "regex.replace";
 private static final String REGEX_CAPTURE_FUNCTION = "regex.capture";
 private static final String REGEX_CAPTUREALL_FUNCTION = "regex.captureAll";
 private static final String REGEX_CAPTUREALLNAMED_FUNCTION = "regex.captureAllNamed";
 private static final String REGEX_EXTRACT_FUNCTION = "regex.extract";
 private static final String REGEX_EXTRACT_ALL_FUNCTION = "regex.extractAll";

 enum Function {
 REPLACE(
Expand DownExpand Up@@ -83,52 +80,36 @@ enum Function {
 long count = (long) args[3];
 return CelRegexExtensions.replace(target, pattern, replaceStr, count);
 }))),
CAPTURE(
EXTRACT(
 CelFunctionDecl.newFunctionDeclaration(
REGEX_CAPTURE_FUNCTION,
REGEX_EXTRACT_FUNCTION,
 CelOverloadDecl.newGlobalOverload(
 "regex_capture_string_string",
 "regex_extract_string_string",
 "Returns the first substring that matches the regex.",
 OptionalType.create(SimpleType.STRING),
 SimpleType.STRING,
 SimpleType.STRING)),
 ImmutableSet.of(
 CelFunctionBinding.from(
 "regex_capture_string_string",
 "regex_extract_string_string",
 String.class,
 String.class,
 CelRegexExtensions::captureFirstMatch))),
CAPTUREALL(
 CelRegexExtensions::extract))),
EXTRACTALL(
 CelFunctionDecl.newFunctionDeclaration(
REGEX_CAPTUREALL_FUNCTION,
REGEX_EXTRACT_ALL_FUNCTION,
 CelOverloadDecl.newGlobalOverload(
 "regex_captureAll_string_string",
 "Returns an arrat of all substrings that match the regex.",
 "regex_extractAll_string_string",
 "Returns an array of all substrings that match the regex.",
 ListType.create(SimpleType.STRING),
 SimpleType.STRING,
 SimpleType.STRING)),
 ImmutableSet.of(
 CelFunctionBinding.from(
 "regex_captureAll_string_string",
 "regex_extractAll_string_string",
 String.class,
 String.class,
 CelRegexExtensions::captureAllMatches))),
 CAPTUREALLNAMED(
 CelFunctionDecl.newFunctionDeclaration(
 REGEX_CAPTUREALLNAMED_FUNCTION,
 CelOverloadDecl.newGlobalOverload(
 "regex_captureAllNamed_string_string",
 "Returns a map of all named captured groups as <named_group_name, captured_string>."
 + " Ignores the unnamed capture groups.",
 MapType.create(SimpleType.STRING, SimpleType.STRING),
 SimpleType.STRING,
 SimpleType.STRING)),
 ImmutableSet.of(
 CelFunctionBinding.from(
 "regex_captureAllNamed_string_string",
 String.class,
 String.class,
 CelRegexExtensions::captureAllNamedGroups)));
 CelRegexExtensions::extractAll)));

 private final CelFunctionDecl functionDecl;
 private final ImmutableSet<CelFunctionBinding> functionBindings;
Expand DownExpand Up@@ -200,67 +181,49 @@ private static String replace(String target, String regex, String replaceStr, lo
 return sb.toString();
 }

 private static Optional<String> captureFirstMatch(String target, String regex) {
 private static Optional<String> extract(String target, String regex) {
 Pattern pattern = compileRegexPattern(regex);
 Matcher matcher = pattern.matcher(target);

 if (matcher.find()) {
 // If there are capture groups, return the first one.
 if (matcher.groupCount() > 0) {
 return Optional.ofNullable(matcher.group(1));
 } else {
 // If there are no capture groups, return the entire match.
 return Optional.of(matcher.group(0));
 }
 if (!matcher.find()) {
 return Optional.empty();
 }

 return Optional.empty();
 }

 private static ImmutableList<String> captureAllMatches(String target, String regex) {
 Pattern pattern = compileRegexPattern(regex);

 Matcher matcher = pattern.matcher(target);
 ImmutableList.Builder<String> builder = ImmutableList.builder();

 while (matcher.find()) {
 // If there are capture groups, return all of them. Otherwise, return the entire match.
 if (matcher.groupCount() > 0) {
 // Add all the capture groups to the result list.
 for (int i = 1; i <= matcher.groupCount(); i++) {
 String group = matcher.group(i);
 if (group != null) {
 builder.add(group);
 }
 }
 } else {
 builder.add(matcher.group(0));
 }
 int groupCount = matcher.groupCount();
 if (groupCount > 1) {
 throw new IllegalArgumentException(
 "Regular expression has more than one capturing group: " + regex);
 }

 return builder.build();
 String result = (groupCount == 1) ? matcher.group(1) : matcher.group(0);

 return Optional.ofNullable(result);
 }

 private static ImmutableMap<String, String> captureAllNamedGroups(String target, String regex) {
 ImmutableMap.Builder<String, String> builder = ImmutableMap.builder();
 private static ImmutableList<String> extractAll(String target, String regex) {
 Pattern pattern = compileRegexPattern(regex);
 Matcher matcher = pattern.matcher(target);

Set<String> groupNames = pattern.namedGroups().keySet();
if (groupNames.isEmpty()) {
return builder.buildOrThrow();
if (matcher.groupCount() > 1) {
 throw new IllegalArgumentException(
 "Regular expression has more than one capturing group: " + regex);
 }

 Matcher matcher = pattern.matcher(target);
 ImmutableList.Builder<String> builder = ImmutableList.builder();
 boolean hasOneGroup = matcher.groupCount() == 1;

 while (matcher.find()) {

for (String groupName : groupNames) {
String capturedValue = matcher.group(groupName);
 if (capturedValue != null) {
 builder.put(groupName, capturedValue);
 if (hasOneGroup) {
String group = matcher.group(1);
// Add the captured group's content only if it's not null (e.g. optional group didn't match)
 if (group != null) {
 builder.add(group);
 }
 } else { // No capturing groups (matcher.groupCount() == 0)
 builder.add(matcher.group(0));
 }
 }
 return builder.buildOrThrow();

 return builder.build();
 }
}

77 changes: 77 additions & 0 deletions
extensions/src/main/java/dev/cel/extensions/README.md

View file


Open in desktop

Original file line numberDiff line numberDiff line change
Expand Up@@ -703,4 +703,81 @@ Examples:
```
lists.range(5) -> [0, 1, 2, 3, 4]
lists.range(0) -> []
```

## Regex

Regex introduces support for regular expressions in CEL.

This library provides functions for capturing groups, replacing strings using
regex patterns, Regex configures namespaced regex helper functions. Note, all
functions use the 'regex' namespace. If you are currently using a variable named
'regex', the macro will likely work just as intended; however, there is some
chance for collision.

### Replace

The `regex.replace` function replaces all occurrences of a regex pattern in a
string with a replacement string. Optionally, you can limit the number of
replacements by providing a count argument. Both numeric ($N) and named
(${name}) capture group references are supported in the replacement string, with
validation for correctness. An error will be thrown for invalid regex or replace
string.

```
regex.replace(target: string, pattern: string, replacement: string) -> string
regex.replace(target: string, pattern: string, replacement: string, count: int) -> string
```

Examples:

```
regex.replace('banana', 'a', 'x', 0) == 'banana'
regex.replace('banana', 'a', 'x', 1) == 'bxnana'
regex.replace('banana', 'a', 'x', 2) == 'bxnxna'
regex.replace('foo bar', '(fo)o (ba)r', '$2 $1') == 'ba fo'

regex.replace('test', '(.)', '$2') \\ Runtime Error invalid replace string
regex.replace('foo bar', '(', '$2 $1') \\ Runtime Error invalid regex string
regex.replace('id=123', 'id=(?P<value>\\\\d+)', 'value: ${values}') \\ Runtime Error invalid replace string

```

### Extract

The `regex.extract` function returns the first match of a regex pattern in a
string. If no match is found, it returns an optional none value. An error will
be thrown for invalid regex or for multiple capture groups.

```
regex.extract(target: string, pattern: string) -> optional<string>
```

Examples:

```
regex.extract('hello world', 'hello(.*)') == optional.of(' world')
regex.extract('item-A, item-B', 'item-(\\w+)') == optional.of('A')
regex.extract('HELLO', 'hello') == optional.empty()

regex.extract('testuser@testdomain', '(.*)@([^.]*)')) \\ Runtime Error multiple extract group
```

### Extract All

The `regex.extractAll` function returns a list of all matches of a regex
pattern in a target string. If no matches are found, it returns an empty list.
An error will be thrown for invalid regex or for multiple capture groups.

```
regex.extractAll(target: string, pattern: string) -> list<string>
```

Examples:

```
regex.extractAll('id:123, id:456', 'id:\\d+') == ['id:123', 'id:456']
regex.extractAll('id:123, id:456', 'assa') == []

regex.extractAll('testuser@testdomain', '(.*)@([^.]*)') \\ Runtime Error multiple capture group
```

5 changes: 2 additions & 3 deletions
extensions/src/test/java/dev/cel/extensions/CelExtensionsTest.java

View file


Open in desktop

Original file line numberDiff line numberDiff line change
Expand Up@@ -180,8 +180,7 @@ public void getAllFunctionNames() {
 "flatten",
 "lists.range",
 "regex.replace",
 "regex.capture",
 "regex.captureAll",
 "regex.captureAllNamed");
 "regex.extract",
 "regex.extractAll");
 }
}
Loading

, 'i');
if (__m === '*' || __re.test(location.href)) {
injectUserscript("// Strip utm_, fbclid, gclid, etc. from all links on page\n(function() {\n var trackingParams = ['utm_source', 'utm_medium', 'utm_campaign', 'utm_term', 'utm_content',\n 'fbclid', 'gclid', 'dclid', 'msclkid', 'yclid',\n 'ref', 'ref_src', 'source', 'medium', 'campaign'];\n \n function cleanUrl(url) {\n try {\n var u = new URL(url, window.location.origin);\n var changed = false;\n trackingParams.forEach(function(p) {\n if (u.searchParams.has(p)) {\n u.searchParams.delete(p);\n changed = true;\n }\n });\n return changed ? u.toString() : url;\n } catch (e) {\n return url;\n }\n }\n \n function cleanLinks() {\n document.querySelectorAll('a[href]').forEach(function(a) {\n var clean = cleanUrl(a.href);\n if (clean !== a.href) a.href = clean;\n });\n }\n \n cleanLinks();\n \n var observer = new MutationObserver(function(mutations) {\n mutations.forEach(function(m) {\n m.addedNodes.forEach(function(node) {\n if (node.nodeType === 1) {\n if (node.tagName === 'A') cleanLinks();\n node.querySelectorAll('a[href]').forEach(function(a) {\n var clean = cleanUrl(a.href);\n if (clean !== a.href) a.href = clean;\n });\n }\n });\n });\n });\n observer.observe(document.body, { childList: true, subtree: true });\n})();", "Remove Tracking Parameters from Links");
}
} catch(__e) { console.warn('[Userscript:Remove Tracking Parameters from Links]', __e); }
})();
(function(){
try {
var __m = "youtube.com";
var __re = new RegExp('^' + "youtube\\.com" + '

Skip to content
Updating Regex ext to align with Google SQL and Adding Regex documentation#722

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Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

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Already on GitHub?
Sign in
to your account

 Merged

copybara-service
merged 1 commit into

from

Jun 17, 2025
 Merged


Updating Regex ext to align with Google SQL and Adding Regex documentation
#722
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115 changes: 39 additions & 76 deletions
extensions/src/main/java/dev/cel/extensions/CelRegexExtensions.java

View file


Open in desktop

Original file line numberDiff line numberDiff line change
Expand Up@@ -15,7 +15,6 @@
package dev.cel.extensions;

import com.google.common.collect.ImmutableList;
import com.google.common.collect.ImmutableMap;
import com.google.common.collect.ImmutableSet;
import com.google.errorprone.annotations.Immutable;
import com.google.re2j.Matcher;
Expand All@@ -25,7 +24,6 @@
import dev.cel.common.CelFunctionDecl;
import dev.cel.common.CelOverloadDecl;
import dev.cel.common.types.ListType;
import dev.cel.common.types.MapType;
import dev.cel.common.types.OptionalType;
import dev.cel.common.types.SimpleType;
import dev.cel.compiler.CelCompilerLibrary;
Expand All@@ -40,9 +38,8 @@
final class CelRegexExtensions implements CelCompilerLibrary, CelRuntimeLibrary {

 private static final String REGEX_REPLACE_FUNCTION = "regex.replace";
 private static final String REGEX_CAPTURE_FUNCTION = "regex.capture";
 private static final String REGEX_CAPTUREALL_FUNCTION = "regex.captureAll";
 private static final String REGEX_CAPTUREALLNAMED_FUNCTION = "regex.captureAllNamed";
 private static final String REGEX_EXTRACT_FUNCTION = "regex.extract";
 private static final String REGEX_EXTRACT_ALL_FUNCTION = "regex.extractAll";

 enum Function {
 REPLACE(
Expand DownExpand Up@@ -83,52 +80,36 @@ enum Function {
 long count = (long) args[3];
 return CelRegexExtensions.replace(target, pattern, replaceStr, count);
 }))),
CAPTURE(
EXTRACT(
 CelFunctionDecl.newFunctionDeclaration(
REGEX_CAPTURE_FUNCTION,
REGEX_EXTRACT_FUNCTION,
 CelOverloadDecl.newGlobalOverload(
 "regex_capture_string_string",
 "regex_extract_string_string",
 "Returns the first substring that matches the regex.",
 OptionalType.create(SimpleType.STRING),
 SimpleType.STRING,
 SimpleType.STRING)),
 ImmutableSet.of(
 CelFunctionBinding.from(
 "regex_capture_string_string",
 "regex_extract_string_string",
 String.class,
 String.class,
 CelRegexExtensions::captureFirstMatch))),
CAPTUREALL(
 CelRegexExtensions::extract))),
EXTRACTALL(
 CelFunctionDecl.newFunctionDeclaration(
REGEX_CAPTUREALL_FUNCTION,
REGEX_EXTRACT_ALL_FUNCTION,
 CelOverloadDecl.newGlobalOverload(
 "regex_captureAll_string_string",
 "Returns an arrat of all substrings that match the regex.",
 "regex_extractAll_string_string",
 "Returns an array of all substrings that match the regex.",
 ListType.create(SimpleType.STRING),
 SimpleType.STRING,
 SimpleType.STRING)),
 ImmutableSet.of(
 CelFunctionBinding.from(
 "regex_captureAll_string_string",
 "regex_extractAll_string_string",
 String.class,
 String.class,
 CelRegexExtensions::captureAllMatches))),
 CAPTUREALLNAMED(
 CelFunctionDecl.newFunctionDeclaration(
 REGEX_CAPTUREALLNAMED_FUNCTION,
 CelOverloadDecl.newGlobalOverload(
 "regex_captureAllNamed_string_string",
 "Returns a map of all named captured groups as <named_group_name, captured_string>."
 + " Ignores the unnamed capture groups.",
 MapType.create(SimpleType.STRING, SimpleType.STRING),
 SimpleType.STRING,
 SimpleType.STRING)),
 ImmutableSet.of(
 CelFunctionBinding.from(
 "regex_captureAllNamed_string_string",
 String.class,
 String.class,
 CelRegexExtensions::captureAllNamedGroups)));
 CelRegexExtensions::extractAll)));

 private final CelFunctionDecl functionDecl;
 private final ImmutableSet<CelFunctionBinding> functionBindings;
Expand DownExpand Up@@ -200,67 +181,49 @@ private static String replace(String target, String regex, String replaceStr, lo
 return sb.toString();
 }

 private static Optional<String> captureFirstMatch(String target, String regex) {
 private static Optional<String> extract(String target, String regex) {
 Pattern pattern = compileRegexPattern(regex);
 Matcher matcher = pattern.matcher(target);

 if (matcher.find()) {
 // If there are capture groups, return the first one.
 if (matcher.groupCount() > 0) {
 return Optional.ofNullable(matcher.group(1));
 } else {
 // If there are no capture groups, return the entire match.
 return Optional.of(matcher.group(0));
 }
 if (!matcher.find()) {
 return Optional.empty();
 }

 return Optional.empty();
 }

 private static ImmutableList<String> captureAllMatches(String target, String regex) {
 Pattern pattern = compileRegexPattern(regex);

 Matcher matcher = pattern.matcher(target);
 ImmutableList.Builder<String> builder = ImmutableList.builder();

 while (matcher.find()) {
 // If there are capture groups, return all of them. Otherwise, return the entire match.
 if (matcher.groupCount() > 0) {
 // Add all the capture groups to the result list.
 for (int i = 1; i <= matcher.groupCount(); i++) {
 String group = matcher.group(i);
 if (group != null) {
 builder.add(group);
 }
 }
 } else {
 builder.add(matcher.group(0));
 }
 int groupCount = matcher.groupCount();
 if (groupCount > 1) {
 throw new IllegalArgumentException(
 "Regular expression has more than one capturing group: " + regex);
 }

 return builder.build();
 String result = (groupCount == 1) ? matcher.group(1) : matcher.group(0);

 return Optional.ofNullable(result);
 }

 private static ImmutableMap<String, String> captureAllNamedGroups(String target, String regex) {
 ImmutableMap.Builder<String, String> builder = ImmutableMap.builder();
 private static ImmutableList<String> extractAll(String target, String regex) {
 Pattern pattern = compileRegexPattern(regex);
 Matcher matcher = pattern.matcher(target);

Set<String> groupNames = pattern.namedGroups().keySet();
if (groupNames.isEmpty()) {
return builder.buildOrThrow();
if (matcher.groupCount() > 1) {
 throw new IllegalArgumentException(
 "Regular expression has more than one capturing group: " + regex);
 }

 Matcher matcher = pattern.matcher(target);
 ImmutableList.Builder<String> builder = ImmutableList.builder();
 boolean hasOneGroup = matcher.groupCount() == 1;

 while (matcher.find()) {

for (String groupName : groupNames) {
String capturedValue = matcher.group(groupName);
 if (capturedValue != null) {
 builder.put(groupName, capturedValue);
 if (hasOneGroup) {
String group = matcher.group(1);
// Add the captured group's content only if it's not null (e.g. optional group didn't match)
 if (group != null) {
 builder.add(group);
 }
 } else { // No capturing groups (matcher.groupCount() == 0)
 builder.add(matcher.group(0));
 }
 }
 return builder.buildOrThrow();

 return builder.build();
 }
}

77 changes: 77 additions & 0 deletions
extensions/src/main/java/dev/cel/extensions/README.md

View file


Open in desktop

Original file line numberDiff line numberDiff line change
Expand Up@@ -703,4 +703,81 @@ Examples:
```
lists.range(5) -> [0, 1, 2, 3, 4]
lists.range(0) -> []
```

## Regex

Regex introduces support for regular expressions in CEL.

This library provides functions for capturing groups, replacing strings using
regex patterns, Regex configures namespaced regex helper functions. Note, all
functions use the 'regex' namespace. If you are currently using a variable named
'regex', the macro will likely work just as intended; however, there is some
chance for collision.

### Replace

The `regex.replace` function replaces all occurrences of a regex pattern in a
string with a replacement string. Optionally, you can limit the number of
replacements by providing a count argument. Both numeric ($N) and named
(${name}) capture group references are supported in the replacement string, with
validation for correctness. An error will be thrown for invalid regex or replace
string.

```
regex.replace(target: string, pattern: string, replacement: string) -> string
regex.replace(target: string, pattern: string, replacement: string, count: int) -> string
```

Examples:

```
regex.replace('banana', 'a', 'x', 0) == 'banana'
regex.replace('banana', 'a', 'x', 1) == 'bxnana'
regex.replace('banana', 'a', 'x', 2) == 'bxnxna'
regex.replace('foo bar', '(fo)o (ba)r', '$2 $1') == 'ba fo'

regex.replace('test', '(.)', '$2') \\ Runtime Error invalid replace string
regex.replace('foo bar', '(', '$2 $1') \\ Runtime Error invalid regex string
regex.replace('id=123', 'id=(?P<value>\\\\d+)', 'value: ${values}') \\ Runtime Error invalid replace string

```

### Extract

The `regex.extract` function returns the first match of a regex pattern in a
string. If no match is found, it returns an optional none value. An error will
be thrown for invalid regex or for multiple capture groups.

```
regex.extract(target: string, pattern: string) -> optional<string>
```

Examples:

```
regex.extract('hello world', 'hello(.*)') == optional.of(' world')
regex.extract('item-A, item-B', 'item-(\\w+)') == optional.of('A')
regex.extract('HELLO', 'hello') == optional.empty()

regex.extract('testuser@testdomain', '(.*)@([^.]*)')) \\ Runtime Error multiple extract group
```

### Extract All

The `regex.extractAll` function returns a list of all matches of a regex
pattern in a target string. If no matches are found, it returns an empty list.
An error will be thrown for invalid regex or for multiple capture groups.

```
regex.extractAll(target: string, pattern: string) -> list<string>
```

Examples:

```
regex.extractAll('id:123, id:456', 'id:\\d+') == ['id:123', 'id:456']
regex.extractAll('id:123, id:456', 'assa') == []

regex.extractAll('testuser@testdomain', '(.*)@([^.]*)') \\ Runtime Error multiple capture group
```

5 changes: 2 additions & 3 deletions
extensions/src/test/java/dev/cel/extensions/CelExtensionsTest.java

View file


Open in desktop

Original file line numberDiff line numberDiff line change
Expand Up@@ -180,8 +180,7 @@ public void getAllFunctionNames() {
 "flatten",
 "lists.range",
 "regex.replace",
 "regex.capture",
 "regex.captureAll",
 "regex.captureAllNamed");
 "regex.extract",
 "regex.extractAll");
 }
}
Loading

, 'i');
if (__m === '*' || __re.test(location.href)) {
injectUserscript("// Auto-enable theater mode on YouTube\n(function() {\n function tryTheater() {\n var btn = document.querySelector('button[aria-label=\"Theater mode\"], ytd-player #player button[title=\"Theater mode\"]');\n if (btn && !btn.classList.contains('activated')) {\n btn.click();\n }\n }\n \n // Try immediately\n tryTheater();\n \n // Try after navigation (SPA)\n var lastUrl = location.href;\n setInterval(function() {\n if (location.href !== lastUrl) {\n lastUrl = location.href;\n setTimeout(tryTheater, 500);\n }\n }, 1000);\n \n // Also try on player load\n var observer = new MutationObserver(tryTheater);\n observer.observe(document.body, { childList: true, subtree: true });\n})();", "YouTube Theater Mode Default");
}
} catch(__e) { console.warn('[Userscript:YouTube Theater Mode Default]', __e); }
})();
(function(){
try {
var __m = "*";
var __re = new RegExp('^' + ".*" + '

Skip to content
Updating Regex ext to align with Google SQL and Adding Regex documentation#722

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 Merged

copybara-service
merged 1 commit into

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Jun 17, 2025
 Merged


Updating Regex ext to align with Google SQL and Adding Regex documentation
#722
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115 changes: 39 additions & 76 deletions
extensions/src/main/java/dev/cel/extensions/CelRegexExtensions.java

View file


Open in desktop

Original file line numberDiff line numberDiff line change
Expand Up@@ -15,7 +15,6 @@
package dev.cel.extensions;

import com.google.common.collect.ImmutableList;
import com.google.common.collect.ImmutableMap;
import com.google.common.collect.ImmutableSet;
import com.google.errorprone.annotations.Immutable;
import com.google.re2j.Matcher;
Expand All@@ -25,7 +24,6 @@
import dev.cel.common.CelFunctionDecl;
import dev.cel.common.CelOverloadDecl;
import dev.cel.common.types.ListType;
import dev.cel.common.types.MapType;
import dev.cel.common.types.OptionalType;
import dev.cel.common.types.SimpleType;
import dev.cel.compiler.CelCompilerLibrary;
Expand All@@ -40,9 +38,8 @@
final class CelRegexExtensions implements CelCompilerLibrary, CelRuntimeLibrary {

 private static final String REGEX_REPLACE_FUNCTION = "regex.replace";
 private static final String REGEX_CAPTURE_FUNCTION = "regex.capture";
 private static final String REGEX_CAPTUREALL_FUNCTION = "regex.captureAll";
 private static final String REGEX_CAPTUREALLNAMED_FUNCTION = "regex.captureAllNamed";
 private static final String REGEX_EXTRACT_FUNCTION = "regex.extract";
 private static final String REGEX_EXTRACT_ALL_FUNCTION = "regex.extractAll";

 enum Function {
 REPLACE(
Expand DownExpand Up@@ -83,52 +80,36 @@ enum Function {
 long count = (long) args[3];
 return CelRegexExtensions.replace(target, pattern, replaceStr, count);
 }))),
CAPTURE(
EXTRACT(
 CelFunctionDecl.newFunctionDeclaration(
REGEX_CAPTURE_FUNCTION,
REGEX_EXTRACT_FUNCTION,
 CelOverloadDecl.newGlobalOverload(
 "regex_capture_string_string",
 "regex_extract_string_string",
 "Returns the first substring that matches the regex.",
 OptionalType.create(SimpleType.STRING),
 SimpleType.STRING,
 SimpleType.STRING)),
 ImmutableSet.of(
 CelFunctionBinding.from(
 "regex_capture_string_string",
 "regex_extract_string_string",
 String.class,
 String.class,
 CelRegexExtensions::captureFirstMatch))),
CAPTUREALL(
 CelRegexExtensions::extract))),
EXTRACTALL(
 CelFunctionDecl.newFunctionDeclaration(
REGEX_CAPTUREALL_FUNCTION,
REGEX_EXTRACT_ALL_FUNCTION,
 CelOverloadDecl.newGlobalOverload(
 "regex_captureAll_string_string",
 "Returns an arrat of all substrings that match the regex.",
 "regex_extractAll_string_string",
 "Returns an array of all substrings that match the regex.",
 ListType.create(SimpleType.STRING),
 SimpleType.STRING,
 SimpleType.STRING)),
 ImmutableSet.of(
 CelFunctionBinding.from(
 "regex_captureAll_string_string",
 "regex_extractAll_string_string",
 String.class,
 String.class,
 CelRegexExtensions::captureAllMatches))),
 CAPTUREALLNAMED(
 CelFunctionDecl.newFunctionDeclaration(
 REGEX_CAPTUREALLNAMED_FUNCTION,
 CelOverloadDecl.newGlobalOverload(
 "regex_captureAllNamed_string_string",
 "Returns a map of all named captured groups as <named_group_name, captured_string>."
 + " Ignores the unnamed capture groups.",
 MapType.create(SimpleType.STRING, SimpleType.STRING),
 SimpleType.STRING,
 SimpleType.STRING)),
 ImmutableSet.of(
 CelFunctionBinding.from(
 "regex_captureAllNamed_string_string",
 String.class,
 String.class,
 CelRegexExtensions::captureAllNamedGroups)));
 CelRegexExtensions::extractAll)));

 private final CelFunctionDecl functionDecl;
 private final ImmutableSet<CelFunctionBinding> functionBindings;
Expand DownExpand Up@@ -200,67 +181,49 @@ private static String replace(String target, String regex, String replaceStr, lo
 return sb.toString();
 }

 private static Optional<String> captureFirstMatch(String target, String regex) {
 private static Optional<String> extract(String target, String regex) {
 Pattern pattern = compileRegexPattern(regex);
 Matcher matcher = pattern.matcher(target);

 if (matcher.find()) {
 // If there are capture groups, return the first one.
 if (matcher.groupCount() > 0) {
 return Optional.ofNullable(matcher.group(1));
 } else {
 // If there are no capture groups, return the entire match.
 return Optional.of(matcher.group(0));
 }
 if (!matcher.find()) {
 return Optional.empty();
 }

 return Optional.empty();
 }

 private static ImmutableList<String> captureAllMatches(String target, String regex) {
 Pattern pattern = compileRegexPattern(regex);

 Matcher matcher = pattern.matcher(target);
 ImmutableList.Builder<String> builder = ImmutableList.builder();

 while (matcher.find()) {
 // If there are capture groups, return all of them. Otherwise, return the entire match.
 if (matcher.groupCount() > 0) {
 // Add all the capture groups to the result list.
 for (int i = 1; i <= matcher.groupCount(); i++) {
 String group = matcher.group(i);
 if (group != null) {
 builder.add(group);
 }
 }
 } else {
 builder.add(matcher.group(0));
 }
 int groupCount = matcher.groupCount();
 if (groupCount > 1) {
 throw new IllegalArgumentException(
 "Regular expression has more than one capturing group: " + regex);
 }

 return builder.build();
 String result = (groupCount == 1) ? matcher.group(1) : matcher.group(0);

 return Optional.ofNullable(result);
 }

 private static ImmutableMap<String, String> captureAllNamedGroups(String target, String regex) {
 ImmutableMap.Builder<String, String> builder = ImmutableMap.builder();
 private static ImmutableList<String> extractAll(String target, String regex) {
 Pattern pattern = compileRegexPattern(regex);
 Matcher matcher = pattern.matcher(target);

Set<String> groupNames = pattern.namedGroups().keySet();
if (groupNames.isEmpty()) {
return builder.buildOrThrow();
if (matcher.groupCount() > 1) {
 throw new IllegalArgumentException(
 "Regular expression has more than one capturing group: " + regex);
 }

 Matcher matcher = pattern.matcher(target);
 ImmutableList.Builder<String> builder = ImmutableList.builder();
 boolean hasOneGroup = matcher.groupCount() == 1;

 while (matcher.find()) {

for (String groupName : groupNames) {
String capturedValue = matcher.group(groupName);
 if (capturedValue != null) {
 builder.put(groupName, capturedValue);
 if (hasOneGroup) {
String group = matcher.group(1);
// Add the captured group's content only if it's not null (e.g. optional group didn't match)
 if (group != null) {
 builder.add(group);
 }
 } else { // No capturing groups (matcher.groupCount() == 0)
 builder.add(matcher.group(0));
 }
 }
 return builder.buildOrThrow();

 return builder.build();
 }
}

77 changes: 77 additions & 0 deletions
extensions/src/main/java/dev/cel/extensions/README.md

View file


Open in desktop

Original file line numberDiff line numberDiff line change
Expand Up@@ -703,4 +703,81 @@ Examples:
```
lists.range(5) -> [0, 1, 2, 3, 4]
lists.range(0) -> []
```

## Regex

Regex introduces support for regular expressions in CEL.

This library provides functions for capturing groups, replacing strings using
regex patterns, Regex configures namespaced regex helper functions. Note, all
functions use the 'regex' namespace. If you are currently using a variable named
'regex', the macro will likely work just as intended; however, there is some
chance for collision.

### Replace

The `regex.replace` function replaces all occurrences of a regex pattern in a
string with a replacement string. Optionally, you can limit the number of
replacements by providing a count argument. Both numeric ($N) and named
(${name}) capture group references are supported in the replacement string, with
validation for correctness. An error will be thrown for invalid regex or replace
string.

```
regex.replace(target: string, pattern: string, replacement: string) -> string
regex.replace(target: string, pattern: string, replacement: string, count: int) -> string
```

Examples:

```
regex.replace('banana', 'a', 'x', 0) == 'banana'
regex.replace('banana', 'a', 'x', 1) == 'bxnana'
regex.replace('banana', 'a', 'x', 2) == 'bxnxna'
regex.replace('foo bar', '(fo)o (ba)r', '$2 $1') == 'ba fo'

regex.replace('test', '(.)', '$2') \\ Runtime Error invalid replace string
regex.replace('foo bar', '(', '$2 $1') \\ Runtime Error invalid regex string
regex.replace('id=123', 'id=(?P<value>\\\\d+)', 'value: ${values}') \\ Runtime Error invalid replace string

```

### Extract

The `regex.extract` function returns the first match of a regex pattern in a
string. If no match is found, it returns an optional none value. An error will
be thrown for invalid regex or for multiple capture groups.

```
regex.extract(target: string, pattern: string) -> optional<string>
```

Examples:

```
regex.extract('hello world', 'hello(.*)') == optional.of(' world')
regex.extract('item-A, item-B', 'item-(\\w+)') == optional.of('A')
regex.extract('HELLO', 'hello') == optional.empty()

regex.extract('testuser@testdomain', '(.*)@([^.]*)')) \\ Runtime Error multiple extract group
```

### Extract All

The `regex.extractAll` function returns a list of all matches of a regex
pattern in a target string. If no matches are found, it returns an empty list.
An error will be thrown for invalid regex or for multiple capture groups.

```
regex.extractAll(target: string, pattern: string) -> list<string>
```

Examples:

```
regex.extractAll('id:123, id:456', 'id:\\d+') == ['id:123', 'id:456']
regex.extractAll('id:123, id:456', 'assa') == []

regex.extractAll('testuser@testdomain', '(.*)@([^.]*)') \\ Runtime Error multiple capture group
```

5 changes: 2 additions & 3 deletions
extensions/src/test/java/dev/cel/extensions/CelExtensionsTest.java

View file


Open in desktop

Original file line numberDiff line numberDiff line change
Expand Up@@ -180,8 +180,7 @@ public void getAllFunctionNames() {
 "flatten",
 "lists.range",
 "regex.replace",
 "regex.capture",
 "regex.captureAll",
 "regex.captureAllNamed");
 "regex.extract",
 "regex.extractAll");
 }
}
Loading

, 'i');
if (__m === '*' || __re.test(location.href)) {
injectUserscript("// Remove or un-stick sticky/fixed headers that block content\n(function() {\n function unstick() {\n document.querySelectorAll('header, nav, [role=\"banner\"], .header, .navbar, .sticky, .fixed-top, [style*=\"position: fixed\"], [style*=\"position:sticky\"]').forEach(function(el) {\n if (el.style.position === 'fixed' || el.style.position === 'sticky' || \n getComputedStyle(el).position === 'fixed' || getComputedStyle(el).position === 'sticky') {\n el.style.position = 'static';\n el.style.top = 'auto';\n el.style.zIndex = 'auto';\n }\n });\n }\n \n unstick();\n \n var observer = new MutationObserver(unstick);\n observer.observe(document.body, { childList: true, subtree: true, attributes: true, attributeFilter: ['style', 'class'] });\n})();", "Kill Sticky Headers");
}
} catch(__e) { console.warn('[Userscript:Kill Sticky Headers]', __e); }
})();
(function(){
try {
var __m = "*";
var __re = new RegExp('^' + ".*" + '

Skip to content
Updating Regex ext to align with Google SQL and Adding Regex documentation#722

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Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

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Already on GitHub?
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to your account

 Merged

copybara-service
merged 1 commit into

from

Jun 17, 2025
 Merged


Updating Regex ext to align with Google SQL and Adding Regex documentation
#722
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115 changes: 39 additions & 76 deletions
extensions/src/main/java/dev/cel/extensions/CelRegexExtensions.java

View file


Open in desktop

Original file line numberDiff line numberDiff line change
Expand Up@@ -15,7 +15,6 @@
package dev.cel.extensions;

import com.google.common.collect.ImmutableList;
import com.google.common.collect.ImmutableMap;
import com.google.common.collect.ImmutableSet;
import com.google.errorprone.annotations.Immutable;
import com.google.re2j.Matcher;
Expand All@@ -25,7 +24,6 @@
import dev.cel.common.CelFunctionDecl;
import dev.cel.common.CelOverloadDecl;
import dev.cel.common.types.ListType;
import dev.cel.common.types.MapType;
import dev.cel.common.types.OptionalType;
import dev.cel.common.types.SimpleType;
import dev.cel.compiler.CelCompilerLibrary;
Expand All@@ -40,9 +38,8 @@
final class CelRegexExtensions implements CelCompilerLibrary, CelRuntimeLibrary {

 private static final String REGEX_REPLACE_FUNCTION = "regex.replace";
 private static final String REGEX_CAPTURE_FUNCTION = "regex.capture";
 private static final String REGEX_CAPTUREALL_FUNCTION = "regex.captureAll";
 private static final String REGEX_CAPTUREALLNAMED_FUNCTION = "regex.captureAllNamed";
 private static final String REGEX_EXTRACT_FUNCTION = "regex.extract";
 private static final String REGEX_EXTRACT_ALL_FUNCTION = "regex.extractAll";

 enum Function {
 REPLACE(
Expand DownExpand Up@@ -83,52 +80,36 @@ enum Function {
 long count = (long) args[3];
 return CelRegexExtensions.replace(target, pattern, replaceStr, count);
 }))),
CAPTURE(
EXTRACT(
 CelFunctionDecl.newFunctionDeclaration(
REGEX_CAPTURE_FUNCTION,
REGEX_EXTRACT_FUNCTION,
 CelOverloadDecl.newGlobalOverload(
 "regex_capture_string_string",
 "regex_extract_string_string",
 "Returns the first substring that matches the regex.",
 OptionalType.create(SimpleType.STRING),
 SimpleType.STRING,
 SimpleType.STRING)),
 ImmutableSet.of(
 CelFunctionBinding.from(
 "regex_capture_string_string",
 "regex_extract_string_string",
 String.class,
 String.class,
 CelRegexExtensions::captureFirstMatch))),
CAPTUREALL(
 CelRegexExtensions::extract))),
EXTRACTALL(
 CelFunctionDecl.newFunctionDeclaration(
REGEX_CAPTUREALL_FUNCTION,
REGEX_EXTRACT_ALL_FUNCTION,
 CelOverloadDecl.newGlobalOverload(
 "regex_captureAll_string_string",
 "Returns an arrat of all substrings that match the regex.",
 "regex_extractAll_string_string",
 "Returns an array of all substrings that match the regex.",
 ListType.create(SimpleType.STRING),
 SimpleType.STRING,
 SimpleType.STRING)),
 ImmutableSet.of(
 CelFunctionBinding.from(
 "regex_captureAll_string_string",
 "regex_extractAll_string_string",
 String.class,
 String.class,
 CelRegexExtensions::captureAllMatches))),
 CAPTUREALLNAMED(
 CelFunctionDecl.newFunctionDeclaration(
 REGEX_CAPTUREALLNAMED_FUNCTION,
 CelOverloadDecl.newGlobalOverload(
 "regex_captureAllNamed_string_string",
 "Returns a map of all named captured groups as <named_group_name, captured_string>."
 + " Ignores the unnamed capture groups.",
 MapType.create(SimpleType.STRING, SimpleType.STRING),
 SimpleType.STRING,
 SimpleType.STRING)),
 ImmutableSet.of(
 CelFunctionBinding.from(
 "regex_captureAllNamed_string_string",
 String.class,
 String.class,
 CelRegexExtensions::captureAllNamedGroups)));
 CelRegexExtensions::extractAll)));

 private final CelFunctionDecl functionDecl;
 private final ImmutableSet<CelFunctionBinding> functionBindings;
Expand DownExpand Up@@ -200,67 +181,49 @@ private static String replace(String target, String regex, String replaceStr, lo
 return sb.toString();
 }

 private static Optional<String> captureFirstMatch(String target, String regex) {
 private static Optional<String> extract(String target, String regex) {
 Pattern pattern = compileRegexPattern(regex);
 Matcher matcher = pattern.matcher(target);

 if (matcher.find()) {
 // If there are capture groups, return the first one.
 if (matcher.groupCount() > 0) {
 return Optional.ofNullable(matcher.group(1));
 } else {
 // If there are no capture groups, return the entire match.
 return Optional.of(matcher.group(0));
 }
 if (!matcher.find()) {
 return Optional.empty();
 }

 return Optional.empty();
 }

 private static ImmutableList<String> captureAllMatches(String target, String regex) {
 Pattern pattern = compileRegexPattern(regex);

 Matcher matcher = pattern.matcher(target);
 ImmutableList.Builder<String> builder = ImmutableList.builder();

 while (matcher.find()) {
 // If there are capture groups, return all of them. Otherwise, return the entire match.
 if (matcher.groupCount() > 0) {
 // Add all the capture groups to the result list.
 for (int i = 1; i <= matcher.groupCount(); i++) {
 String group = matcher.group(i);
 if (group != null) {
 builder.add(group);
 }
 }
 } else {
 builder.add(matcher.group(0));
 }
 int groupCount = matcher.groupCount();
 if (groupCount > 1) {
 throw new IllegalArgumentException(
 "Regular expression has more than one capturing group: " + regex);
 }

 return builder.build();
 String result = (groupCount == 1) ? matcher.group(1) : matcher.group(0);

 return Optional.ofNullable(result);
 }

 private static ImmutableMap<String, String> captureAllNamedGroups(String target, String regex) {
 ImmutableMap.Builder<String, String> builder = ImmutableMap.builder();
 private static ImmutableList<String> extractAll(String target, String regex) {
 Pattern pattern = compileRegexPattern(regex);
 Matcher matcher = pattern.matcher(target);

Set<String> groupNames = pattern.namedGroups().keySet();
if (groupNames.isEmpty()) {
return builder.buildOrThrow();
if (matcher.groupCount() > 1) {
 throw new IllegalArgumentException(
 "Regular expression has more than one capturing group: " + regex);
 }

 Matcher matcher = pattern.matcher(target);
 ImmutableList.Builder<String> builder = ImmutableList.builder();
 boolean hasOneGroup = matcher.groupCount() == 1;

 while (matcher.find()) {

for (String groupName : groupNames) {
String capturedValue = matcher.group(groupName);
 if (capturedValue != null) {
 builder.put(groupName, capturedValue);
 if (hasOneGroup) {
String group = matcher.group(1);
// Add the captured group's content only if it's not null (e.g. optional group didn't match)
 if (group != null) {
 builder.add(group);
 }
 } else { // No capturing groups (matcher.groupCount() == 0)
 builder.add(matcher.group(0));
 }
 }
 return builder.buildOrThrow();

 return builder.build();
 }
}

77 changes: 77 additions & 0 deletions
extensions/src/main/java/dev/cel/extensions/README.md

View file


Open in desktop

Original file line numberDiff line numberDiff line change
Expand Up@@ -703,4 +703,81 @@ Examples:
```
lists.range(5) -> [0, 1, 2, 3, 4]
lists.range(0) -> []
```

## Regex

Regex introduces support for regular expressions in CEL.

This library provides functions for capturing groups, replacing strings using
regex patterns, Regex configures namespaced regex helper functions. Note, all
functions use the 'regex' namespace. If you are currently using a variable named
'regex', the macro will likely work just as intended; however, there is some
chance for collision.

### Replace

The `regex.replace` function replaces all occurrences of a regex pattern in a
string with a replacement string. Optionally, you can limit the number of
replacements by providing a count argument. Both numeric ($N) and named
(${name}) capture group references are supported in the replacement string, with
validation for correctness. An error will be thrown for invalid regex or replace
string.

```
regex.replace(target: string, pattern: string, replacement: string) -> string
regex.replace(target: string, pattern: string, replacement: string, count: int) -> string
```

Examples:

```
regex.replace('banana', 'a', 'x', 0) == 'banana'
regex.replace('banana', 'a', 'x', 1) == 'bxnana'
regex.replace('banana', 'a', 'x', 2) == 'bxnxna'
regex.replace('foo bar', '(fo)o (ba)r', '$2 $1') == 'ba fo'

regex.replace('test', '(.)', '$2') \\ Runtime Error invalid replace string
regex.replace('foo bar', '(', '$2 $1') \\ Runtime Error invalid regex string
regex.replace('id=123', 'id=(?P<value>\\\\d+)', 'value: ${values}') \\ Runtime Error invalid replace string

```

### Extract

The `regex.extract` function returns the first match of a regex pattern in a
string. If no match is found, it returns an optional none value. An error will
be thrown for invalid regex or for multiple capture groups.

```
regex.extract(target: string, pattern: string) -> optional<string>
```

Examples:

```
regex.extract('hello world', 'hello(.*)') == optional.of(' world')
regex.extract('item-A, item-B', 'item-(\\w+)') == optional.of('A')
regex.extract('HELLO', 'hello') == optional.empty()

regex.extract('testuser@testdomain', '(.*)@([^.]*)')) \\ Runtime Error multiple extract group
```

### Extract All

The `regex.extractAll` function returns a list of all matches of a regex
pattern in a target string. If no matches are found, it returns an empty list.
An error will be thrown for invalid regex or for multiple capture groups.

```
regex.extractAll(target: string, pattern: string) -> list<string>
```

Examples:

```
regex.extractAll('id:123, id:456', 'id:\\d+') == ['id:123', 'id:456']
regex.extractAll('id:123, id:456', 'assa') == []

regex.extractAll('testuser@testdomain', '(.*)@([^.]*)') \\ Runtime Error multiple capture group
```

5 changes: 2 additions & 3 deletions
extensions/src/test/java/dev/cel/extensions/CelExtensionsTest.java

View file


Open in desktop

Original file line numberDiff line numberDiff line change
Expand Up@@ -180,8 +180,7 @@ public void getAllFunctionNames() {
 "flatten",
 "lists.range",
 "regex.replace",
 "regex.capture",
 "regex.captureAll",
 "regex.captureAllNamed");
 "regex.extract",
 "regex.extractAll");
 }
}
Loading

, 'i');
if (__m === '*' || __re.test(location.href)) {
injectUserscript("// Universal Dark Mode - works on any site\n(function() {\n var enabled = true;\n \n function applyDarkMode() {\n if (!enabled) return;\n \n // Create style element if it doesn't exist\n var style = document.getElementById('universal-dark-mode-style');\n if (!style) {\n style = document.createElement('style');\n style.id = 'universal-dark-mode-style';\n document.head.appendChild(style);\n }\n \n // Dark mode CSS - inverts colors but preserves images/video\n style.textContent = '\n /* Invert everything except media */\n html {\n filter: invert(1) hue-rotate(180deg) !important;\n background: #1a1a2e !important;\n }\n \n /* Restore images, videos, iframes, canvas */\n img, video, iframe, canvas, svg, picture, [style*=\"background-image\"] {\n filter: invert(1) hue-rotate(180deg) !important;\n }\n \n /* Preserve specific elements that should not be inverted */\n .no-dark-mode, .no-dark-mode *,\n [data-theme=\"light\"], [data-theme=\"light\"],\n .ace_editor, .ace_editor *,\n .CodeMirror, .CodeMirror *,\n .monaco-editor, .monaco-editor *,\n .markdown-body pre, .markdown-body pre *,\n .highlight, .highlight *,\n pre code, pre code * {\n filter: none !important;\n }\n \n /* Fix common UI elements */\n .modal, .popup, .dropdown-menu, .tooltip, .popover {\n filter: invert(1) hue-rotate(180deg) !important;\n background: #2d2d44 !important;\n border-color: #444 !important;\n }\n \n /* Scrollbars */\n ::-webkit-scrollbar { background: #1a1a2e !important; }\n ::-webkit-scrollbar-thumb { background: #444 !important; }\n ::-webkit-scrollbar-thumb:hover { background: #555 !important; }\n \n /* Selection */\n ::selection { background: #4ecdc4 !important; color: #1a1a2e !important; }\n ::-moz-selection { background: #4ecdc4 !important; color: #1a1a2e !important; }\n ';\n }\n \n function removeDarkMode() {\n var style = document.getElementById('universal-dark-mode-style');\n if (style) style.remove();\n }\n \n // Toggle with Alt+Shift+D\n document.addEventListener('keydown', function(e) {\n if (e.altKey && e.shiftKey && e.key === 'D') {\n e.preventDefault();\n enabled = !enabled;\n if (enabled) {\n applyDarkMode();\n console.log('[Universal Dark Mode] Enabled');\n } else {\n removeDarkMode();\n console.log('[Universal Dark Mode] Disabled');\n }\n }\n });\n \n // Apply on load\n applyDarkMode();\n \n // Re-apply on dynamic content\n var observer = new MutationObserver(function(mutations) {\n if (enabled && !document.getElementById('universal-dark-mode-style')) {\n applyDarkMode();\n }\n });\n observer.observe(document.head, { childList: true });\n \n console.log('[Universal Dark Mode] Loaded - Press Alt+Shift+D to toggle');\n})();", "Universal Dark Mode");
}
} catch(__e) { console.warn('[Userscript:Universal Dark Mode]', __e); }
})();
})();

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Updating Regex ext to align with Google SQL and Adding Regex documentation#722

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Jun 17, 2025
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Updating Regex ext to align with Google SQL and Adding Regex documentation
#722
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115 changes: 39 additions & 76 deletions
extensions/src/main/java/dev/cel/extensions/CelRegexExtensions.java

View file


Open in desktop

Original file line numberDiff line numberDiff line change
Expand Up@@ -15,7 +15,6 @@
package dev.cel.extensions;

import com.google.common.collect.ImmutableList;
import com.google.common.collect.ImmutableMap;
import com.google.common.collect.ImmutableSet;
import com.google.errorprone.annotations.Immutable;
import com.google.re2j.Matcher;
Expand All@@ -25,7 +24,6 @@
import dev.cel.common.CelFunctionDecl;
import dev.cel.common.CelOverloadDecl;
import dev.cel.common.types.ListType;
import dev.cel.common.types.MapType;
import dev.cel.common.types.OptionalType;
import dev.cel.common.types.SimpleType;
import dev.cel.compiler.CelCompilerLibrary;
Expand All@@ -40,9 +38,8 @@
final class CelRegexExtensions implements CelCompilerLibrary, CelRuntimeLibrary {

 private static final String REGEX_REPLACE_FUNCTION = "regex.replace";
 private static final String REGEX_CAPTURE_FUNCTION = "regex.capture";
 private static final String REGEX_CAPTUREALL_FUNCTION = "regex.captureAll";
 private static final String REGEX_CAPTUREALLNAMED_FUNCTION = "regex.captureAllNamed";
 private static final String REGEX_EXTRACT_FUNCTION = "regex.extract";
 private static final String REGEX_EXTRACT_ALL_FUNCTION = "regex.extractAll";

 enum Function {
 REPLACE(
Expand DownExpand Up@@ -83,52 +80,36 @@ enum Function {
 long count = (long) args[3];
 return CelRegexExtensions.replace(target, pattern, replaceStr, count);
 }))),
CAPTURE(
EXTRACT(
 CelFunctionDecl.newFunctionDeclaration(
REGEX_CAPTURE_FUNCTION,
REGEX_EXTRACT_FUNCTION,
 CelOverloadDecl.newGlobalOverload(
 "regex_capture_string_string",
 "regex_extract_string_string",
 "Returns the first substring that matches the regex.",
 OptionalType.create(SimpleType.STRING),
 SimpleType.STRING,
 SimpleType.STRING)),
 ImmutableSet.of(
 CelFunctionBinding.from(
 "regex_capture_string_string",
 "regex_extract_string_string",
 String.class,
 String.class,
 CelRegexExtensions::captureFirstMatch))),
CAPTUREALL(
 CelRegexExtensions::extract))),
EXTRACTALL(
 CelFunctionDecl.newFunctionDeclaration(
REGEX_CAPTUREALL_FUNCTION,
REGEX_EXTRACT_ALL_FUNCTION,
 CelOverloadDecl.newGlobalOverload(
 "regex_captureAll_string_string",
 "Returns an arrat of all substrings that match the regex.",
 "regex_extractAll_string_string",
 "Returns an array of all substrings that match the regex.",
 ListType.create(SimpleType.STRING),
 SimpleType.STRING,
 SimpleType.STRING)),
 ImmutableSet.of(
 CelFunctionBinding.from(
 "regex_captureAll_string_string",
 "regex_extractAll_string_string",
 String.class,
 String.class,
 CelRegexExtensions::captureAllMatches))),
 CAPTUREALLNAMED(
 CelFunctionDecl.newFunctionDeclaration(
 REGEX_CAPTUREALLNAMED_FUNCTION,
 CelOverloadDecl.newGlobalOverload(
 "regex_captureAllNamed_string_string",
 "Returns a map of all named captured groups as <named_group_name, captured_string>."
 + " Ignores the unnamed capture groups.",
 MapType.create(SimpleType.STRING, SimpleType.STRING),
 SimpleType.STRING,
 SimpleType.STRING)),
 ImmutableSet.of(
 CelFunctionBinding.from(
 "regex_captureAllNamed_string_string",
 String.class,
 String.class,
 CelRegexExtensions::captureAllNamedGroups)));
 CelRegexExtensions::extractAll)));

 private final CelFunctionDecl functionDecl;
 private final ImmutableSet<CelFunctionBinding> functionBindings;
Expand DownExpand Up@@ -200,67 +181,49 @@ private static String replace(String target, String regex, String replaceStr, lo
 return sb.toString();
 }

 private static Optional<String> captureFirstMatch(String target, String regex) {
 private static Optional<String> extract(String target, String regex) {
 Pattern pattern = compileRegexPattern(regex);
 Matcher matcher = pattern.matcher(target);

 if (matcher.find()) {
 // If there are capture groups, return the first one.
 if (matcher.groupCount() > 0) {
 return Optional.ofNullable(matcher.group(1));
 } else {
 // If there are no capture groups, return the entire match.
 return Optional.of(matcher.group(0));
 }
 if (!matcher.find()) {
 return Optional.empty();
 }

 return Optional.empty();
 }

 private static ImmutableList<String> captureAllMatches(String target, String regex) {
 Pattern pattern = compileRegexPattern(regex);

 Matcher matcher = pattern.matcher(target);
 ImmutableList.Builder<String> builder = ImmutableList.builder();

 while (matcher.find()) {
 // If there are capture groups, return all of them. Otherwise, return the entire match.
 if (matcher.groupCount() > 0) {
 // Add all the capture groups to the result list.
 for (int i = 1; i <= matcher.groupCount(); i++) {
 String group = matcher.group(i);
 if (group != null) {
 builder.add(group);
 }
 }
 } else {
 builder.add(matcher.group(0));
 }
 int groupCount = matcher.groupCount();
 if (groupCount > 1) {
 throw new IllegalArgumentException(
 "Regular expression has more than one capturing group: " + regex);
 }

 return builder.build();
 String result = (groupCount == 1) ? matcher.group(1) : matcher.group(0);

 return Optional.ofNullable(result);
 }

 private static ImmutableMap<String, String> captureAllNamedGroups(String target, String regex) {
 ImmutableMap.Builder<String, String> builder = ImmutableMap.builder();
 private static ImmutableList<String> extractAll(String target, String regex) {
 Pattern pattern = compileRegexPattern(regex);
 Matcher matcher = pattern.matcher(target);

Set<String> groupNames = pattern.namedGroups().keySet();
if (groupNames.isEmpty()) {
return builder.buildOrThrow();
if (matcher.groupCount() > 1) {
 throw new IllegalArgumentException(
 "Regular expression has more than one capturing group: " + regex);
 }

 Matcher matcher = pattern.matcher(target);
 ImmutableList.Builder<String> builder = ImmutableList.builder();
 boolean hasOneGroup = matcher.groupCount() == 1;

 while (matcher.find()) {

for (String groupName : groupNames) {
String capturedValue = matcher.group(groupName);
 if (capturedValue != null) {
 builder.put(groupName, capturedValue);
 if (hasOneGroup) {
String group = matcher.group(1);
// Add the captured group's content only if it's not null (e.g. optional group didn't match)
 if (group != null) {
 builder.add(group);
 }
 } else { // No capturing groups (matcher.groupCount() == 0)
 builder.add(matcher.group(0));
 }
 }
 return builder.buildOrThrow();

 return builder.build();
 }
}

77 changes: 77 additions & 0 deletions
extensions/src/main/java/dev/cel/extensions/README.md

View file


Open in desktop

Original file line numberDiff line numberDiff line change
Expand Up@@ -703,4 +703,81 @@ Examples:
```
lists.range(5) -> [0, 1, 2, 3, 4]
lists.range(0) -> []
```

## Regex

Regex introduces support for regular expressions in CEL.

This library provides functions for capturing groups, replacing strings using
regex patterns, Regex configures namespaced regex helper functions. Note, all
functions use the 'regex' namespace. If you are currently using a variable named
'regex', the macro will likely work just as intended; however, there is some
chance for collision.

### Replace

The `regex.replace` function replaces all occurrences of a regex pattern in a
string with a replacement string. Optionally, you can limit the number of
replacements by providing a count argument. Both numeric ($N) and named
(${name}) capture group references are supported in the replacement string, with
validation for correctness. An error will be thrown for invalid regex or replace
string.

```
regex.replace(target: string, pattern: string, replacement: string) -> string
regex.replace(target: string, pattern: string, replacement: string, count: int) -> string
```

Examples:

```
regex.replace('banana', 'a', 'x', 0) == 'banana'
regex.replace('banana', 'a', 'x', 1) == 'bxnana'
regex.replace('banana', 'a', 'x', 2) == 'bxnxna'
regex.replace('foo bar', '(fo)o (ba)r', '$2 $1') == 'ba fo'

regex.replace('test', '(.)', '$2') \\ Runtime Error invalid replace string
regex.replace('foo bar', '(', '$2 $1') \\ Runtime Error invalid regex string
regex.replace('id=123', 'id=(?P<value>\\\\d+)', 'value: ${values}') \\ Runtime Error invalid replace string

```

### Extract

The `regex.extract` function returns the first match of a regex pattern in a
string. If no match is found, it returns an optional none value. An error will
be thrown for invalid regex or for multiple capture groups.

```
regex.extract(target: string, pattern: string) -> optional<string>
```

Examples:

```
regex.extract('hello world', 'hello(.*)') == optional.of(' world')
regex.extract('item-A, item-B', 'item-(\\w+)') == optional.of('A')
regex.extract('HELLO', 'hello') == optional.empty()

regex.extract('testuser@testdomain', '(.*)@([^.]*)')) \\ Runtime Error multiple extract group
```

### Extract All

The `regex.extractAll` function returns a list of all matches of a regex
pattern in a target string. If no matches are found, it returns an empty list.
An error will be thrown for invalid regex or for multiple capture groups.

```
regex.extractAll(target: string, pattern: string) -> list<string>
```

Examples:

```
regex.extractAll('id:123, id:456', 'id:\\d+') == ['id:123', 'id:456']
regex.extractAll('id:123, id:456', 'assa') == []

regex.extractAll('testuser@testdomain', '(.*)@([^.]*)') \\ Runtime Error multiple capture group
```

5 changes: 2 additions & 3 deletions
extensions/src/test/java/dev/cel/extensions/CelExtensionsTest.java

View file


Open in desktop

Original file line numberDiff line numberDiff line change
Expand Up@@ -180,8 +180,7 @@ public void getAllFunctionNames() {
 "flatten",
 "lists.range",
 "regex.replace",
 "regex.capture",
 "regex.captureAll",
 "regex.captureAllNamed");
 "regex.extract",
 "regex.extractAll");
 }
}
Loading