Add Text replace using regex to placeholders

common/src/commonMain/kotlin/com/artemchep/keyguard/common/service/placeholder/impl/TextReplaceRegexPlaceholder.kt

@@ -0,0 +1,34 @@
+package com.artemchep.keyguard.common.service.placeholder.impl
+
+import com.artemchep.keyguard.common.io.IO
+import com.artemchep.keyguard.common.io.ioEffect
+import com.artemchep.keyguard.common.service.placeholder.Placeholder
+import com.artemchep.keyguard.common.service.placeholder.util.Parser
+
+class TextReplaceRegexPlaceholder(
+) : Placeholder {
+    private val parser = Parser(
+        name = "t-replace-rx",
+        count = 3,
+    )
+
+    override fun get(
+        key: String,
+    ): IO<String?>? {
+        val params = parser.parse(key)
+            ?: return null
+        val regex = params.params.getOrNull(0)
+        val replacement = params.params.getOrNull(1)
+        if (
+            regex == null ||
+            replacement == null
+        ) {
+            return null
+        }
+
+        return ioEffect {
+            val rg = regex.toRegex()
+            rg.replace(params.value, replacement)
+        }
+    }
+}

common/src/commonMain/kotlin/com/artemchep/keyguard/feature/home/vault/screen/VaultViewStateProducer.kt

@@ -73,6 +73,7 @@ import com.artemchep.keyguard.common.service.placeholder.impl.CommentPlaceholder
 import com.artemchep.keyguard.common.service.placeholder.impl.CustomPlaceholder
 import com.artemchep.keyguard.common.service.placeholder.impl.DateTimePlaceholder
 import com.artemchep.keyguard.common.service.placeholder.impl.EnvironmentPlaceholder
+import com.artemchep.keyguard.common.service.placeholder.impl.TextReplaceRegexPlaceholder
 import com.artemchep.keyguard.common.service.placeholder.impl.TextTransformPlaceholder
 import com.artemchep.keyguard.common.service.placeholder.impl.UrlPlaceholder
 import com.artemchep.keyguard.common.service.placeholder.placeholderFormat
@@ -474,6 +475,7 @@ fun vaultViewScreenState(
                     CommentPlaceholder(),
                     CustomPlaceholder(secretOrNull),
                     DateTimePlaceholder(),
+                    TextReplaceRegexPlaceholder(),
                     TextTransformPlaceholder(),
                     EnvironmentPlaceholder(),
                 )

wiki/PLACEHOLDERS.md

@@ -68,7 +68,24 @@ Note: `{base}` supports exactly the same parts as `{url}` and is identical to it
 
 #### Text transformation
 
-Convert text to the other representation.
+##### Replace text using regular expression
+
+```
+t-replace-rx:/text/search/replace/
+```
+the first symbol after `:` defines the separator. It may be any symbol except `{` and `}`. Trailing separator symbol is required.
+
+_Example_:
+
+Let the username field contain the email address 'username@example.com', then:
+```
+> {t-replace-rx:/{username}/.*@(.*)/$1/}
+example.com
+```
+
+for more info how it works, see the [underlying implementation's documentation](https://kotlinlang.org/api/latest/jvm/stdlib/kotlin.text/-regex/replace.html)
+
+##### Convert text to the other representation
 
 ```
 t-conv:/value/type/