feat: regex converter

baRSS.xcodeproj/project.pbxproj

@@ -13,6 +13,10 @@
 		541C67C32255470B004D2CE6 /* SettingsAppearance.m in Sources */ = {isa = PBXBuildFile; fileRef = 541C67C22255470B004D2CE6 /* SettingsAppearance.m */; };
 		54209E942117325100F3B5EF /* DrawImage.m in Sources */ = {isa = PBXBuildFile; fileRef = 54209E932117325100F3B5EF /* DrawImage.m */; };
 		54229F552E02491A0019ACB0 /* TinySVG.m in Sources */ = {isa = PBXBuildFile; fileRef = 54229F542E02491A0019ACB0 /* TinySVG.m */; };
+		54253C7F2C47303A00742695 /* RegexConverter+Ext.m in Sources */ = {isa = PBXBuildFile; fileRef = 54253C7E2C47303A00742695 /* RegexConverter+Ext.m */; };
+		54253C932C49BFCD00742695 /* RegexConverterModal.m in Sources */ = {isa = PBXBuildFile; fileRef = 54253C8A2C49A92400742695 /* RegexConverterModal.m */; };
+		54253C942C49BFDC00742695 /* RegexConverterController.m in Sources */ = {isa = PBXBuildFile; fileRef = 54253C872C49A6A800742695 /* RegexConverterController.m */; };
+		54253C952C49BFE400742695 /* RegexConverterView.m in Sources */ = {isa = PBXBuildFile; fileRef = 54253C842C47369000742695 /* RegexConverterView.m */; };
 		544B011A2114B41200386E5C /* ModalSheet.m in Sources */ = {isa = PBXBuildFile; fileRef = 544B01192114B41200386E5C /* ModalSheet.m */; };
 		544B011D2114EE9100386E5C /* AppHook.m in Sources */ = {isa = PBXBuildFile; fileRef = 544B011C2114EE9100386E5C /* AppHook.m */; };
 		54501010230E9C8600F0B165 /* FeedDownload.m in Sources */ = {isa = PBXBuildFile; fileRef = 5450100F230E9C8600F0B165 /* FeedDownload.m */; };
@@ -45,6 +49,7 @@
 		54B749E0220636200022CC6D /* FeedArticle+Ext.m in Sources */ = {isa = PBXBuildFile; fileRef = 54B749DF220635CD0022CC6D /* FeedArticle+Ext.m */; };
 		54BB048921FD2AB500C303A5 /* NSDate+Ext.m in Sources */ = {isa = PBXBuildFile; fileRef = 54BB048821FD2AB500C303A5 /* NSDate+Ext.m */; };
 		54BF444A22D0F4F300660096 /* AppIcon.icns in Resources */ = {isa = PBXBuildFile; fileRef = 54BF444922D0F4F300660096 /* AppIcon.icns */; };
+		54D10DDB2C6E930F0008F621 /* RegexFeed.m in Sources */ = {isa = PBXBuildFile; fileRef = 54D10DDA2C6E930F0008F621 /* RegexFeed.m */; };
 		54D55D7322E624CD00057B98 /* SettingsFeeds+DragDrop.m in Sources */ = {isa = PBXBuildFile; fileRef = 54D55D7222E624CD00057B98 /* SettingsFeeds+DragDrop.m */; };
 		54D857CE227C5785001BA1C8 /* RefreshStatisticsView.m in Sources */ = {isa = PBXBuildFile; fileRef = 54D857CD227C5785001BA1C8 /* RefreshStatisticsView.m */; };
 		54DD9F1323D1D6B000B1EAA6 /* NSColor+Ext.m in Sources */ = {isa = PBXBuildFile; fileRef = 54DD9F1223D1D6B000B1EAA6 /* NSColor+Ext.m */; };
@@ -130,6 +135,14 @@
 		54209E932117325100F3B5EF /* DrawImage.m */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.objc; path = DrawImage.m; sourceTree = "<group>"; };
 		54229F532E02491A0019ACB0 /* TinySVG.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; path = TinySVG.h; sourceTree = "<group>"; };
 		54229F542E02491A0019ACB0 /* TinySVG.m */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.objc; path = TinySVG.m; sourceTree = "<group>"; };
+		54253C7A2C47303A00742695 /* RegexConverter+Ext.h */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.c.h; path = "RegexConverter+Ext.h"; sourceTree = "<group>"; };
+		54253C7E2C47303A00742695 /* RegexConverter+Ext.m */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.c.objc; path = "RegexConverter+Ext.m"; sourceTree = "<group>"; };
+		54253C832C47368F00742695 /* RegexConverterView.h */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.c.h; path = RegexConverterView.h; sourceTree = "<group>"; };
+		54253C842C47369000742695 /* RegexConverterView.m */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.c.objc; path = RegexConverterView.m; sourceTree = "<group>"; };
+		54253C872C49A6A800742695 /* RegexConverterController.m */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.c.objc; path = RegexConverterController.m; sourceTree = "<group>"; };
+		54253C882C49A6A800742695 /* RegexConverterController.h */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.c.h; path = RegexConverterController.h; sourceTree = "<group>"; };
+		54253C8A2C49A92400742695 /* RegexConverterModal.m */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.c.objc; path = RegexConverterModal.m; sourceTree = "<group>"; };
+		54253C8B2C49A92400742695 /* RegexConverterModal.h */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.c.h; path = RegexConverterModal.h; sourceTree = "<group>"; };
 		544B01182114B41200386E5C /* ModalSheet.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; path = ModalSheet.h; sourceTree = "<group>"; };
 		544B01192114B41200386E5C /* ModalSheet.m */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.objc; path = ModalSheet.m; sourceTree = "<group>"; };
 		544B011B2114EE9100386E5C /* AppHook.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; path = AppHook.h; sourceTree = "<group>"; };
@@ -190,6 +203,8 @@
 		54BB048721FD2AB500C303A5 /* NSDate+Ext.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; path = "NSDate+Ext.h"; sourceTree = "<group>"; };
 		54BB048821FD2AB500C303A5 /* NSDate+Ext.m */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.objc; path = "NSDate+Ext.m"; sourceTree = "<group>"; };
 		54BF444922D0F4F300660096 /* AppIcon.icns */ = {isa = PBXFileReference; lastKnownFileType = image.icns; path = AppIcon.icns; sourceTree = "<group>"; };
+		54D10DD92C6E930F0008F621 /* RegexFeed.h */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.c.h; path = RegexFeed.h; sourceTree = "<group>"; };
+		54D10DDA2C6E930F0008F621 /* RegexFeed.m */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.c.objc; path = RegexFeed.m; sourceTree = "<group>"; };
 		54D55D7122E624CD00057B98 /* SettingsFeeds+DragDrop.h */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.c.h; path = "SettingsFeeds+DragDrop.h"; sourceTree = "<group>"; };
 		54D55D7222E624CD00057B98 /* SettingsFeeds+DragDrop.m */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.c.objc; path = "SettingsFeeds+DragDrop.m"; sourceTree = "<group>"; };
 		54D857CC227C5785001BA1C8 /* RefreshStatisticsView.h */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.c.h; path = RefreshStatisticsView.h; sourceTree = "<group>"; };
@@ -240,6 +255,21 @@
 			path = "Status Bar Menu";
 			sourceTree = "<group>";
 		};
+		54253C862C49A5A900742695 /* Regex Editor */ = {
+			isa = PBXGroup;
+			children = (
+				54253C8B2C49A92400742695 /* RegexConverterModal.h */,
+				54253C8A2C49A92400742695 /* RegexConverterModal.m */,
+				54253C882C49A6A800742695 /* RegexConverterController.h */,
+				54253C872C49A6A800742695 /* RegexConverterController.m */,
+				54253C832C47368F00742695 /* RegexConverterView.h */,
+				54253C842C47369000742695 /* RegexConverterView.m */,
+				54D10DD92C6E930F0008F621 /* RegexFeed.h */,
+				54D10DDA2C6E930F0008F621 /* RegexFeed.m */,
+			);
+			path = "Regex Editor";
+			sourceTree = "<group>";
+		};
 		544936F721F1E51E00DEE9AA /* NSCategories */ = {
 			isa = PBXGroup;
 			children = (
@@ -298,6 +328,8 @@
 				5477D34D21233C62002BA27F /* FeedGroup+Ext.m */,
 				540F704321B6C16C0022E69D /* FeedMeta+Ext.h */,
 				540F704421B6C16C0022E69D /* FeedMeta+Ext.m */,
+				54253C7A2C47303A00742695 /* RegexConverter+Ext.h */,
+				54253C7E2C47303A00742695 /* RegexConverter+Ext.m */,
 				54B749DE220635BE0022CC6D /* FeedArticle+Ext.h */,
 				54B749DF220635CD0022CC6D /* FeedArticle+Ext.m */,
 			);
@@ -344,6 +376,7 @@
 				541A90EF21257D4F002680A6 /* Status Bar Menu */,
 				54A07A8322105E0800082C51 /* Core Data */,
 				54AD4E04230084FD000AE386 /* Feed Import */,
+				54253C862C49A5A900742695 /* Regex Editor */,
 				546FC44D2118B357007CC3A3 /* Preferences */,
 				54ACC28A21061B3C0020715F /* Info.plist */,
 				54F7101322EE0DDA006985D1 /* Artwork */,
@@ -606,8 +639,10 @@
 			isa = PBXSourcesBuildPhase;
 			buildActionMask = 2147483647;
 			files = (
+				54253C932C49BFCD00742695 /* RegexConverterModal.m in Sources */,
 				54B51704226DC339006C1B29 /* ModalFeedEditView.m in Sources */,
 				54AD4E0C2301853D000AE386 /* NSString+Ext.m in Sources */,
+				54D10DDB2C6E930F0008F621 /* RegexFeed.m in Sources */,
 				546A6A2C22C584AF0034E806 /* SettingsAppearanceView.m in Sources */,
 				54E9CF32225914300023696F /* SettingsAbout.m in Sources */,
 				54B749E0220636200022CC6D /* FeedArticle+Ext.m in Sources */,
@@ -619,6 +654,7 @@
 				54DD9F1323D1D6B000B1EAA6 /* NSColor+Ext.m in Sources */,
 				54ACC29521061E270020715F /* UpdateScheduler.m in Sources */,
 				54BB048921FD2AB500C303A5 /* NSDate+Ext.m in Sources */,
+				54253C7F2C47303A00742695 /* RegexConverter+Ext.m in Sources */,
 				5477D34E21233C62002BA27F /* FeedGroup+Ext.m in Sources */,
 				54B6F14A231551B3002C94C9 /* FaviconDownload.m in Sources */,
 				54E4446C2329AE0600BBF481 /* NSError+Ext.m in Sources */,
@@ -642,11 +678,13 @@
 				541C67C32255470B004D2CE6 /* SettingsAppearance.m in Sources */,
 				54B749DA2204A85C0022CC6D /* BarStatusItem.m in Sources */,
 				546FC43D21188AD5007CC3A3 /* SettingsFeeds.m in Sources */,
+				54253C952C49BFE400742695 /* RegexConverterView.m in Sources */,
 				548C6D0A230C33DE003A1AAF /* NSURL+Ext.m in Sources */,
 				54E88320211B509D00064188 /* ModalFeedEdit.m in Sources */,
 				54195883218A061100581B79 /* Feed+Ext.m in Sources */,
 				54501010230E9C8600F0B165 /* FeedDownload.m in Sources */,
 				54209E942117325100F3B5EF /* DrawImage.m in Sources */,
+				54253C942C49BFDC00742695 /* RegexConverterController.m in Sources */,
 				54FE73D021220DEC003EAC65 /* StoreCoordinator.m in Sources */,
 				54A07A7F220E04CF00082C51 /* NSFetchRequest+Ext.m in Sources */,
 			);

baRSS/Core Data/Feed+Ext.m

@@ -89,6 +89,8 @@
 			[localSet removeObject:stored];
 			if (stored.sortIndex != currentIndex)
 				stored.sortIndex = currentIndex; // Ensures block of ascending indices
+			// replace local values with remote changes (if any)
+			[stored updateArticleIfChanged:article];
 		} else {
 			FeedArticle *newArticle = [FeedArticle newArticle:article inContext:self.managedObjectContext];
 			newArticle.sortIndex = currentIndex;

baRSS/Core Data/FeedArticle+Ext.h

@@ -6,6 +6,7 @@ NS_ASSUME_NONNULL_BEGIN
 
 @interface FeedArticle (Ext)
 + (instancetype)newArticle:(RSParsedArticle*)entry inContext:(NSManagedObjectContext*)moc;
+- (void)updateArticleIfChanged:(RSParsedArticle*)entry;
 - (NSMenuItem*)newMenuItem;
 @end
 

baRSS/Core Data/FeedArticle+Ext.m

@@ -25,6 +25,16 @@
 	return fa;
 }
 
+- (void)updateArticleIfChanged:(RSParsedArticle*)entry {
+	[self setGuidIfChanged:entry.guid];
+	[self setTitleIfChanged:entry.title];
+	[self setAuthorIfChanged:entry.author];
+	[self setAbstractIfChanged:(entry.abstract.length > 0) ? [entry.abstract htmlToPlainText] : nil];
+	[self setBodyIfChanged:(entry.body.length > 0) ? [entry.body htmlToPlainText] : nil];
+	[self setLinkIfChanged:(entry.link.length > 0) ? entry.link : entry.guid];
+	[self setPublishedIfChanged:entry.datePublished ? entry.datePublished : entry.dateModified];
+}
+
 /// @return Full or truncated article title, based on user preference in settings.
 - (NSString*)shortArticleName {
 	NSString *title = self.title;
@@ -71,4 +81,78 @@
 	[moc reset];
 }
 
+
+#pragma mark - Setter -
+
+
+/// Set @c guid attribute but only if value differs.
+- (void)setGuidIfChanged:(nullable NSString*)guid {
+	if (guid.length == 0) {
+		if (self.guid.length > 0)
+			self.guid = nil; // nullify empty strings
+	} else if (![self.guid isEqualToString: guid]) {
+		self.guid = guid;
+	}
+}
+
+/// Set @c link attribute but only if value differs.
+- (void)setLinkIfChanged:(nullable NSString*)link {
+	if (link.length == 0) {
+		if (self.link.length > 0)
+			self.link = nil; // nullify empty strings
+	} else if (![self.link isEqualToString: link]) {
+		self.link = link;
+	}
+}
+
+/// Set @c title attribute but only if value differs.
+- (void)setTitleIfChanged:(nullable NSString*)title {
+	if (title.length == 0) {
+		if (self.title.length > 0)
+			self.title = nil; // nullify empty strings
+	} else if (![self.title isEqualToString: title]) {
+		self.title = title;
+	}
+}
+
+/// Set @c abstract attribute but only if value differs.
+- (void)setAbstractIfChanged:(nullable NSString*)abstract {
+	if (abstract.length == 0) {
+		if (self.abstract.length > 0)
+			self.abstract = nil; // nullify empty strings
+	} else if (![self.abstract isEqualToString: abstract]) {
+		self.abstract = abstract;
+	}
+}
+
+/// Set @c body attribute but only if value differs.
+- (void)setBodyIfChanged:(nullable NSString*)body {
+	if (body.length == 0) {
+		if (self.body.length > 0)
+			self.body = nil; // nullify empty strings
+	} else if (![self.body isEqualToString: body]) {
+		self.body = body;
+	}
+}
+
+/// Set @c author attribute but only if value differs.
+- (void)setAuthorIfChanged:(nullable NSString*)author {
+	if (author.length == 0) {
+		if (self.author.length > 0)
+			self.author = nil; // nullify empty strings
+	} else if (![self.author isEqualToString: author]) {
+		self.author = author;
+	}
+}
+
+/// Set @c published attribute but only if value differs.
+- (void)setPublishedIfChanged:(nullable NSDate*)published {
+	if (!published) {
+		if (self.published)
+			self.published = nil; // nullify empty date
+	} else if (![self.published isEqualToDate: published]) {
+		self.published = published;
+	}
+}
+
 @end

baRSS/Core Data/RegexConverter+Ext.h

@@ -0,0 +1,16 @@
+@import Cocoa;
+#import "RegexConverter+CoreDataClass.h"
+
+NS_ASSUME_NONNULL_BEGIN
+
+@interface RegexConverter (Ext)
++ (instancetype)newInContext:(NSManagedObjectContext*)moc;
+- (void)setEntryIfChanged:(nullable NSString*)pattern;
+- (void)setHrefIfChanged:(nullable NSString*)pattern;
+- (void)setTitleIfChanged:(nullable NSString*)pattern;
+- (void)setDescIfChanged:(nullable NSString*)pattern;
+- (void)setDateIfChanged:(nullable NSString*)pattern;
+- (void)setDateFormatIfChanged:(nullable NSString*)pattern;
+@end
+
+NS_ASSUME_NONNULL_END

baRSS/Core Data/RegexConverter+Ext.m

@@ -0,0 +1,70 @@
+#import "RegexConverter+Ext.h"
+
+@implementation RegexConverter (Ext)
+
+/// Create new instance
++ (instancetype)newInContext:(NSManagedObjectContext*)moc {
+	return [[RegexConverter alloc] initWithEntity:[RegexConverter entity] insertIntoManagedObjectContext:moc];
+}
+
+/// Set @c entry attribute but only if value differs.
+- (void)setEntryIfChanged:(nullable NSString*)pattern {
+	if (pattern.length == 0) {
+		if (self.entry.length > 0)
+			self.entry = nil; // nullify empty strings
+	} else if (![self.entry isEqualToString: pattern]) {
+		self.entry = pattern;
+	}
+}
+
+/// Set @c href attribute but only if value differs.
+- (void)setHrefIfChanged:(nullable NSString*)pattern {
+	if (pattern.length == 0) {
+		if (self.href.length > 0)
+			self.href = nil; // nullify empty strings
+	} else if (![self.href isEqualToString: pattern]) {
+		self.href = pattern;
+	}
+}
+
+/// Set @c title attribute but only if value differs.
+- (void)setTitleIfChanged:(nullable NSString*)pattern {
+	if (pattern.length == 0) {
+		if (self.title.length > 0)
+			self.title = nil; // nullify empty strings
+	} else if (![self.title isEqualToString: pattern]) {
+		self.title = pattern;
+	}
+}
+
+/// Set @c desc attribute but only if value differs.
+- (void)setDescIfChanged:(nullable NSString*)pattern {
+	if (pattern.length == 0) {
+		if (self.desc.length > 0)
+			self.desc = nil; // nullify empty strings
+	} else if (![self.desc isEqualToString: pattern]) {
+		self.desc = pattern;
+	}
+}
+
+/// Set @c date attribute but only if value differs.
+- (void)setDateIfChanged:(nullable NSString*)pattern {
+	if (pattern.length == 0) {
+		if (self.date.length > 0)
+			self.date = nil; // nullify empty strings
+	} else if (![self.date isEqualToString: pattern]) {
+		self.date = pattern;
+	}
+}
+
+/// Set @c dateFormat attribute but only if value differs.
+- (void)setDateFormatIfChanged:(nullable NSString*)pattern {
+	if (pattern.length == 0) {
+		if (self.dateFormat.length > 0)
+			self.dateFormat = nil; // nullify empty strings
+	} else if (![self.dateFormat isEqualToString: pattern]) {
+		self.dateFormat = pattern;
+	}
+}
+
+@end

baRSS/DBv1.xcdatamodeld/DBv1.xcdatamodel/contents

@@ -1,52 +1,63 @@
 <?xml version="1.0" encoding="UTF-8" standalone="yes"?>
-<model type="com.apple.IDECoreDataModeler.DataModel" documentVersion="1.0" lastSavedToolsVersion="14460.32" systemVersion="17G8030" minimumToolsVersion="Automatic" sourceLanguage="Objective-C" userDefinedModelVersionIdentifier="v1.0.0">
+<model type="com.apple.IDECoreDataModeler.DataModel" documentVersion="1.0" lastSavedToolsVersion="17709" systemVersion="19H2026" minimumToolsVersion="Automatic" sourceLanguage="Objective-C" userDefinedModelVersionIdentifier="v1.0.0">
     <entity name="Feed" representedClassName="Feed" syncable="YES" codeGenerationType="class">
-        <attribute name="indexPath" optional="YES" attributeType="String" syncable="YES"/>
+        <attribute name="indexPath" optional="YES" attributeType="String"/>
-        <attribute name="link" optional="YES" attributeType="String" syncable="YES"/>
+        <attribute name="link" optional="YES" attributeType="String"/>
-        <attribute name="subtitle" optional="YES" attributeType="String" syncable="YES"/>
+        <attribute name="subtitle" optional="YES" attributeType="String"/>
-        <attribute name="title" optional="YES" attributeType="String" syncable="YES"/>
+        <attribute name="title" optional="YES" attributeType="String"/>
-        <relationship name="articles" optional="YES" toMany="YES" deletionRule="Cascade" destinationEntity="FeedArticle" inverseName="feed" inverseEntity="FeedArticle" syncable="YES"/>
+        <relationship name="articles" optional="YES" toMany="YES" deletionRule="Cascade" destinationEntity="FeedArticle" inverseName="feed" inverseEntity="FeedArticle"/>
-        <relationship name="group" optional="YES" maxCount="1" deletionRule="Nullify" destinationEntity="FeedGroup" inverseName="feed" inverseEntity="FeedGroup" syncable="YES"/>
+        <relationship name="group" optional="YES" maxCount="1" deletionRule="Nullify" destinationEntity="FeedGroup" inverseName="feed" inverseEntity="FeedGroup"/>
-        <relationship name="meta" optional="YES" maxCount="1" deletionRule="Cascade" destinationEntity="FeedMeta" inverseName="feed" inverseEntity="FeedMeta" syncable="YES"/>
+        <relationship name="meta" optional="YES" maxCount="1" deletionRule="Cascade" destinationEntity="FeedMeta" inverseName="feed" inverseEntity="FeedMeta"/>
+        <relationship name="regex" optional="YES" maxCount="1" deletionRule="Cascade" destinationEntity="RegexConverter" inverseName="feed" inverseEntity="RegexConverter"/>
     </entity>
     <entity name="FeedArticle" representedClassName="FeedArticle" syncable="YES" codeGenerationType="class">
-        <attribute name="abstract" optional="YES" attributeType="String" syncable="YES"/>
+        <attribute name="abstract" optional="YES" attributeType="String"/>
-        <attribute name="author" optional="YES" attributeType="String" syncable="YES"/>
+        <attribute name="author" optional="YES" attributeType="String"/>
-        <attribute name="body" optional="YES" attributeType="String" syncable="YES"/>
+        <attribute name="body" optional="YES" attributeType="String"/>
-        <attribute name="guid" optional="YES" attributeType="String" syncable="YES"/>
+        <attribute name="guid" optional="YES" attributeType="String"/>
-        <attribute name="link" optional="YES" attributeType="String" syncable="YES"/>
+        <attribute name="link" optional="YES" attributeType="String"/>
-        <attribute name="published" optional="YES" attributeType="Date" usesScalarValueType="NO" customClassName="NSArray" syncable="YES"/>
+        <attribute name="published" optional="YES" attributeType="Date" usesScalarValueType="NO" customClassName="NSArray"/>
-        <attribute name="sortIndex" optional="YES" attributeType="Integer 32" defaultValueString="0" usesScalarValueType="YES" syncable="YES"/>
+        <attribute name="sortIndex" optional="YES" attributeType="Integer 32" defaultValueString="0" usesScalarValueType="YES"/>
-        <attribute name="title" optional="YES" attributeType="String" syncable="YES"/>
+        <attribute name="title" optional="YES" attributeType="String"/>
-        <attribute name="unread" optional="YES" attributeType="Boolean" defaultValueString="YES" usesScalarValueType="YES" syncable="YES"/>
+        <attribute name="unread" optional="YES" attributeType="Boolean" defaultValueString="YES" usesScalarValueType="YES"/>
-        <relationship name="feed" optional="YES" maxCount="1" deletionRule="Nullify" destinationEntity="Feed" inverseName="articles" inverseEntity="Feed" syncable="YES"/>
+        <relationship name="feed" optional="YES" maxCount="1" deletionRule="Nullify" destinationEntity="Feed" inverseName="articles" inverseEntity="Feed"/>
     </entity>
     <entity name="FeedGroup" representedClassName="FeedGroup" syncable="YES" codeGenerationType="class">
-        <attribute name="name" optional="YES" attributeType="String" syncable="YES"/>
+        <attribute name="name" optional="YES" attributeType="String"/>
-        <attribute name="sortIndex" optional="YES" attributeType="Integer 32" defaultValueString="0" usesScalarValueType="YES" syncable="YES"/>
+        <attribute name="sortIndex" optional="YES" attributeType="Integer 32" defaultValueString="0" usesScalarValueType="YES"/>
-        <attribute name="type" optional="YES" attributeType="Integer 16" defaultValueString="-1" usesScalarValueType="YES" syncable="YES"/>
+        <attribute name="type" optional="YES" attributeType="Integer 16" defaultValueString="-1" usesScalarValueType="YES"/>
-        <relationship name="children" optional="YES" toMany="YES" deletionRule="Cascade" destinationEntity="FeedGroup" inverseName="parent" inverseEntity="FeedGroup" syncable="YES"/>
+        <relationship name="children" optional="YES" toMany="YES" deletionRule="Cascade" destinationEntity="FeedGroup" inverseName="parent" inverseEntity="FeedGroup"/>
-        <relationship name="feed" optional="YES" maxCount="1" deletionRule="Cascade" destinationEntity="Feed" inverseName="group" inverseEntity="Feed" syncable="YES"/>
+        <relationship name="feed" optional="YES" maxCount="1" deletionRule="Cascade" destinationEntity="Feed" inverseName="group" inverseEntity="Feed"/>
-        <relationship name="parent" optional="YES" maxCount="1" deletionRule="Nullify" destinationEntity="FeedGroup" inverseName="children" inverseEntity="FeedGroup" syncable="YES"/>
+        <relationship name="parent" optional="YES" maxCount="1" deletionRule="Nullify" destinationEntity="FeedGroup" inverseName="children" inverseEntity="FeedGroup"/>
     </entity>
     <entity name="FeedMeta" representedClassName="FeedMeta" syncable="YES" codeGenerationType="class">
-        <attribute name="errorCount" optional="YES" attributeType="Integer 16" defaultValueString="0" usesScalarValueType="YES" syncable="YES"/>
+        <attribute name="errorCount" optional="YES" attributeType="Integer 16" defaultValueString="0" usesScalarValueType="YES"/>
-        <attribute name="etag" optional="YES" attributeType="String" syncable="YES"/>
+        <attribute name="etag" optional="YES" attributeType="String"/>
-        <attribute name="modified" optional="YES" attributeType="String" syncable="YES"/>
+        <attribute name="modified" optional="YES" attributeType="String"/>
-        <attribute name="refresh" optional="YES" attributeType="Integer 32" defaultValueString="-1" usesScalarValueType="YES" syncable="YES"/>
+        <attribute name="refresh" optional="YES" attributeType="Integer 32" defaultValueString="-1" usesScalarValueType="YES"/>
-        <attribute name="scheduled" optional="YES" attributeType="Date" usesScalarValueType="NO" syncable="YES"/>
+        <attribute name="scheduled" optional="YES" attributeType="Date" usesScalarValueType="NO"/>
-        <attribute name="url" optional="YES" attributeType="String" syncable="YES"/>
+        <attribute name="url" optional="YES" attributeType="String"/>
-        <relationship name="feed" optional="YES" maxCount="1" deletionRule="Nullify" destinationEntity="Feed" inverseName="meta" inverseEntity="Feed" syncable="YES"/>
+        <relationship name="feed" optional="YES" maxCount="1" deletionRule="Nullify" destinationEntity="Feed" inverseName="meta" inverseEntity="Feed"/>
     </entity>
     <entity name="Options" representedClassName="Options" syncable="YES" codeGenerationType="class">
-        <attribute name="key" optional="YES" attributeType="String" syncable="YES"/>
+        <attribute name="key" optional="YES" attributeType="String"/>
-        <attribute name="value" optional="YES" attributeType="String" syncable="YES"/>
+        <attribute name="value" optional="YES" attributeType="String"/>
+    </entity>
+    <entity name="RegexConverter" representedClassName="RegexConverter" syncable="YES" codeGenerationType="class">
+        <attribute name="date" optional="YES" attributeType="String"/>
+        <attribute name="dateFormat" optional="YES" attributeType="String"/>
+        <attribute name="desc" optional="YES" attributeType="String"/>
+        <attribute name="entry" optional="YES" attributeType="String"/>
+        <attribute name="href" optional="YES" attributeType="String"/>
+        <attribute name="title" optional="YES" attributeType="String"/>
+        <relationship name="feed" optional="YES" maxCount="1" deletionRule="Nullify" destinationEntity="Feed" inverseName="regex" inverseEntity="Feed"/>
     </entity>
     <elements>
-        <element name="Feed" positionX="-278.84765625" positionY="-112.953125" width="128" height="150"/>
+        <element name="Feed" positionX="-278.84765625" positionY="-112.953125" width="128" height="163"/>
         <element name="FeedArticle" positionX="-96.77734375" positionY="-113.83984375" width="128" height="195"/>
         <element name="FeedGroup" positionX="-460.37890625" positionY="-111.62890625" width="130.52734375" height="135"/>
-        <element name="FeedMeta" positionX="-348.02734375" positionY="136.89453125" width="128" height="150"/>
+        <element name="FeedMeta" positionX="-456.265625" positionY="62.41015625" width="128" height="150"/>
-        <element name="Options" positionX="-279" positionY="36" width="128" height="75"/>
+        <element name="Options" positionX="-279.09375" positionY="91.4609375" width="128" height="75"/>
+        <element name="RegexConverter" positionX="-115.984375" positionY="93.1796875" width="128" height="148"/>
     </elements>
 </model>

baRSS/Feed Import/FeedDownload.h

@@ -1,5 +1,5 @@
 @import Cocoa;
-@class RSParsedFeed, RSHTMLMetadataFeedLink, Feed, FaviconDownload;
+@class RSParsedFeed, RSHTMLMetadataFeedLink, Feed, FaviconDownload, RegexConverter;
 @protocol FeedDownloadDelegate;
 
 NS_ASSUME_NONNULL_BEGIN
@@ -14,6 +14,7 @@ NS_ASSUME_NONNULL_BEGIN
 @property (readonly, nullable) RSParsedFeed *xmlfeed;
 @property (readonly, nullable) NSError *error;
 @property (readonly, nullable) NSString *faviconURL;
+@property (readonly, nullable) NSData *rawData;
 
 typedef void (^FeedDownloadBlock)(FeedDownload *sender);
 
@@ -21,6 +22,7 @@ typedef void (^FeedDownloadBlock)(FeedDownload *sender);
 + (instancetype)withURL:(NSString*)url;
 + (instancetype)withFeed:(Feed*)feed forced:(BOOL)flag;
 // Actions
+- (instancetype)withRegex:(nullable RegexConverter *)converter enforce:(BOOL)flag;
 - (instancetype)startWithDelegate:(id<FeedDownloadDelegate>)delegate;
 - (instancetype)startWithBlock:(nonnull FeedDownloadBlock)block;
 - (void)cancel;

baRSS/Feed Import/FeedDownload.m

@@ -6,6 +6,9 @@
 #import "FeedMeta+Ext.h"
 #import "NSError+Ext.h"
 #import "NSURLRequest+Ext.h"
+#import "RegexFeed.h"
+#import "RegexConverter+Ext.h"
+
 
 @interface FeedDownload()
 @property (nonatomic, assign) BOOL respondToSelectFeed, respondToRedirect, respondToEnd;
@@ -20,6 +23,9 @@
 @property (nonatomic, strong) RSParsedFeed *xmlfeed;
 @property (nonatomic, strong) NSError *error;
 @property (nonatomic, strong) NSString *faviconURL;
+@property (nonatomic, strong) NSData *rawData;
+@property (nonatomic, strong) RegexConverter *regexConverter;
+@property (nonatomic, assign) BOOL regexEnforce;
 @end
 
 @implementation FeedDownload
@@ -51,13 +57,20 @@
 	FeedDownload *this = [FeedDownload new];
 	this.assertIsFeedURL = YES;
 	this.request = req;
-	return this;
+	return [this withRegex:feed.regex enforce:false];
 }
 
 //  ---------------------------------------------------------------
 // |  MARK: - Getter & Setter
 //  ---------------------------------------------------------------
 
+/// Set @c .regexConverter for html-processed feeds.
+- (instancetype)withRegex:(RegexConverter *)converter enforce:(BOOL)flag {
+	self.regexConverter = converter;
+	self.regexEnforce = flag;
+	return self;
+}
+
 /// Set delegate and check what methods are implemented.
 - (void)setDelegate:(id<FeedDownloadDelegate>)observer {
 	_delegate = observer;
@@ -134,10 +147,16 @@
 	self.currentDownload = [request dataTask:^(NSData * _Nullable data, NSError * _Nullable error, NSHTTPURLResponse *response) {
 		self.error = error;
 		self.response = response;
+		self.rawData = data;
 		if (!data) { // data = nil if (error || 304)
 			[self performSelectorOnMainThread:@selector(finishAndNotify) withObject:nil waitUntilDone:NO];
 			return;
 		}
+		// if regex is used, no further processing
+		if (self.regexConverter || self.regexEnforce) {
+			[self processWithRegexConverter:self.regexConverter data:data];
+			return;
+		}
 		RSXMLData *xml = [[RSXMLData alloc] initWithData:data url:response.URL];
 		if (!self.assertIsFeedURL && [xml.parserClass isHTMLParser])
 			[self processXMLDataHTML:xml]; // HTML source handling
@@ -146,6 +165,30 @@
 	}];
 }
 
+/// The downloaded source is HTML data and will be parsed with @c RegexConverter
+- (void)processWithRegexConverter:(RegexConverter *)converter data:(NSData *)rawData {
+	NSError *err = nil;
+	if (converter) {
+		NSString *theData = [[NSString alloc] initWithData:rawData encoding:NSUTF8StringEncoding];
+		NSArray<RegexFeedEntry*> *matches = [[RegexFeed from:converter] process:theData error:&err];
+		
+		RSParsedFeed *feed = [[RSParsedFeed alloc] initWithURL:self.request.URL];
+		feed.link = self.request.URL.absoluteString; // needed for group-menu-item-open
+		for (RegexFeedEntry *rxEntry in matches) {
+			RSParsedArticle *article = [feed appendNewArticle];
+			article.link = rxEntry.href;
+			article.title = rxEntry.title;
+			article.body = rxEntry.desc;
+			article.datePublished = rxEntry.date;
+		}
+		self.xmlfeed = feed;
+	} else {
+		self.xmlfeed = nil;
+	}
+	self.error = err;
+	[self performSelectorOnMainThread:@selector(finishAndNotify) withObject:nil waitUntilDone:NO];
+}
+
 /// The downloaded source seems to be HTML data, lets parse it with @c RSXML @c RSHTMLMetadataParser
 - (void)processXMLDataHTML:(RSXMLData*)xml {
 	RSHTMLMetadataParser *parser = [RSHTMLMetadataParser parserWithXMLData:xml];

baRSS/Feed Import/OpmlFile.m

@@ -2,6 +2,7 @@
 #import "OpmlFile.h"
 #import "FeedMeta+Ext.h"
 #import "FeedGroup+Ext.h"
+#import "RegexConverter+Ext.h"
 #import "StoreCoordinator.h"
 #import "Constants.h"
 #import "NSDate+Ext.h"
@@ -120,6 +121,24 @@ static NSInteger RadioGroupSelection(NSView *view) {
 		
 		newFeed.feed.meta.url = [item attributeForKey:OPMLXMLURLKey];
 		newFeed.feed.meta.refresh = interval;
+		
+		// baRSS specific
+		NSString *rxEntry = [item attributeForKey:@"rxEntry"];
+		NSString *rxHref = [item attributeForKey:@"rxHref"];
+		NSString *rxTitle = [item attributeForKey:@"rxTitle"];
+		NSString *rxDesc = [item attributeForKey:@"rxDesc"];
+		NSString *rxDate = [item attributeForKey:@"rxDate"];
+		NSString *rxDateFormat = [item attributeForKey:@"rxDateFormat"];
+		if (rxEntry || rxHref || rxTitle || rxDesc || rxDate || rxDateFormat) {
+			RegexConverter *rx = [RegexConverter newInContext:moc];
+			rx.entry = rxEntry;
+			rx.href = rxHref;
+			rx.title = rxTitle;
+			rx.desc = rxDesc;
+			rx.date = rxDate;
+			rx.dateFormat = rxDateFormat;
+			newFeed.feed.regex = rx;
+		}
 	} else { // GROUP
 		for (NSUInteger i = 0; i < item.children.count; i++) {
 			[self importFeed:item.children[i] parent:newFeed index:(int32_t)i inContext:moc];
@@ -279,6 +298,21 @@ static NSInteger RadioGroupSelection(NSView *view) {
 			[outline addAttribute:[NSXMLNode attributeWithName:OPMLTypeKey stringValue:@"rss"]];
 			NSString *intervalStr = [NSString stringWithFormat:@"%d", item.feed.meta.refresh];
 			[outline addAttribute:[NSXMLNode attributeWithName:@"refreshInterval" stringValue:intervalStr]]; // baRSS specific
+			RegexConverter *rx = item.feed.regex;
+			if (rx) { // baRSS specific
+				if (rx.entry)
+					[outline addAttribute:[NSXMLNode attributeWithName:@"rxEntry" stringValue:rx.entry]];
+				if (rx.href)
+					[outline addAttribute:[NSXMLNode attributeWithName:@"rxHref" stringValue:rx.href]];
+				if (rx.title)
+					[outline addAttribute:[NSXMLNode attributeWithName:@"rxTitle" stringValue:rx.title]];
+				if (rx.desc)
+					[outline addAttribute:[NSXMLNode attributeWithName:@"rxDesc" stringValue:rx.desc]];
+				if (rx.date)
+					[outline addAttribute:[NSXMLNode attributeWithName:@"rxDate" stringValue:rx.date]];
+				if (rx.dateFormat)
+					[outline addAttribute:[NSXMLNode attributeWithName:@"rxDateFormat" stringValue:rx.dateFormat]];
+			}
 			// TODO: option to export unread state?
 		}
 		parent = outline;

baRSS/Preferences/Feeds Tab/ModalFeedEdit.h

@@ -13,6 +13,7 @@ NS_ASSUME_NONNULL_BEGIN
 
 @interface ModalFeedEdit : ModalEditDialog <NSTextFieldDelegate>
 - (void)didClickWarningButton:(NSButton*)sender;
+- (void)openRegexConverter;
 @end
 
 @interface ModalGroupEdit : ModalEditDialog

baRSS/Preferences/Feeds Tab/ModalFeedEdit.m

@@ -11,6 +11,9 @@
 #import "NSView+Ext.h"
 #import "NSDate+Ext.h"
 #import "NSURL+Ext.h"
+#import "RegexConverterController.h"
+#import "RegexConverterModal.h"
+#import "RegexConverter+Ext.h"
 
 // ################################################################
 // #
@@ -59,6 +62,8 @@
 @property (strong) FeedDownload *memFeed;
 @property (weak) FaviconDownload *memIcon;
 @property (strong) RefreshStatisticsView *statisticsView;
+@property (nonatomic, assign) BOOL openRegexAfterDownload;
+@property (weak) id eventMonitor;
 @end
 
 @implementation ModalFeedEdit
@@ -71,6 +76,13 @@
 	self.view.refreshNum.intValue = 30;
 	[NSDate populateUnitsMenu:self.view.refreshUnit selected:TimeUnitMinutes];
 	[self populateTextFields:self.feedGroup];
+	
+	// removed in windowShouldClose:
+	self.eventMonitor = [NSEvent addLocalMonitorForEventsMatchingMask:NSEventMaskFlagsChanged handler:^(NSEvent *event) {
+		BOOL optionKeyActive = ((event.modifierFlags & NSEventModifierFlagOption) != 0);
+		self.view.regexConverterButton.hidden = !self.feedGroup.feed.regex && !optionKeyActive;
+		return event;
+	}];
 }
 
 /// Pre-fill UI control field values with @c FeedGroup properties.
@@ -81,6 +93,7 @@
 	self.view.url.objectValue = fg.feed.meta.url;
 	self.previousURL = self.view.url.stringValue;
 	self.view.favicon.image = [fg.feed iconImage16];
+	self.view.regexConverterButton.hidden = !fg.feed.regex;
 	[NSDate setInterval:fg.feed.meta.refresh forPopup:self.view.refreshUnit andField:self.view.refreshNum animate:NO];
 	[self statsForCoreDataObject];
 }
@@ -131,7 +144,9 @@
 		self.view.name.placeholderString = NSLocalizedString(@"Loading …", nil);
 	}
 	self.previousURL = self.view.url.stringValue;
-	self.memFeed = [[FeedDownload withURL:self.previousURL] startWithDelegate:self];
+	self.memFeed = [[[FeedDownload withURL:self.previousURL]
+					 withRegex:self.feedGroup.feed.regex enforce:self.openRegexAfterDownload]
+					startWithDelegate:self];
 }
 
 /**
@@ -210,7 +225,42 @@
 - (void)downloadComplete {
 	[self.view.spinnerURL stopAnimation:nil];
 	[self.modalSheet setDoneEnabled:YES];
+	
+	if (self.openRegexAfterDownload) {
+		[self openRegexConverter];
 	}
+}
+
+
+#pragma mark - Regex Converter
+
+- (void)openRegexConverter {
+	if (!self.openRegexAfterDownload) {
+		self.openRegexAfterDownload = YES;
+		[self downloadRSS];
+		return;
+	}
+	self.openRegexAfterDownload = NO;
+	
+	// shrink FeedEdit modal size to effectively hide it behind new modal
+	NSRect previous = self.modalSheet.frame;
+	CGFloat minWidthDiff = previous.size.width - self.modalSheet.minSize.width;
+	[self.modalSheet setFrame:NSInsetRect(previous, minWidthDiff / 2.0, 0) display:NO];
+	
+	Feed *feed = self.feedGroup.feed;
+	RegexConverterController *c = [RegexConverterController withData:self.memFeed.rawData andConverter:feed.regex];
+	[self.modalSheet.sheetParent beginCriticalSheet:[c getModalSheet] completionHandler:^(NSModalResponse returnCode) {
+		// reset previous size
+		[self.modalSheet setFrame:previous display:NO];
+		
+		if (returnCode == NSModalResponseOK) {
+			[c applyChanges:feed];
+			self.view.regexConverterButton.hidden = !feed.regex;
+			[self downloadRSS];
+		}
+	}];
+}
+
 
 #pragma mark - Feed Statistics
 
@@ -264,6 +314,7 @@
 		[[NSNotificationCenter defaultCenter] postNotificationName:NSControlTextDidEndEditingNotification object:self.view.url];
 		return NO;
 	}
+	[NSEvent removeMonitor:self.eventMonitor];
 	return YES;
 }
 

baRSS/Preferences/Feeds Tab/ModalFeedEditView.h

@@ -18,6 +18,7 @@ NS_ASSUME_NONNULL_BEGIN
 @property NSPopover *warningPopover;
 @property (strong) IBOutlet NSTextField *warningText;
 @property (strong) IBOutlet NSButton *warningReload;
+@property (strong) IBOutlet NSButton *regexConverterButton;
 
 - (instancetype)initWithController:(ModalFeedEdit*)controller NS_DESIGNATED_INITIALIZER;
 - (instancetype)initWithFrame:(NSRect)frameRect NS_UNAVAILABLE;

baRSS/Preferences/Feeds Tab/ModalFeedEditView.m

@@ -1,6 +1,7 @@
 #import "ModalFeedEditView.h"
 #import "ModalFeedEdit.h"
 #import "NSView+Ext.h"
+#import "Constants.h"
 
 @interface StrictUIntFormatter : NSFormatter
 @end
@@ -25,7 +26,8 @@
 	self.url = [[[NSView inputField:@"https://example.org/feed.rss" width:0] placeIn:self x:x yTop:0] sizeToRight:PAD_S + 18];
 	self.spinnerURL = [[NSView activitySpinner] placeIn:self xRight:1 yTop:2.5];
 	self.favicon = [[[NSView imageView:nil size:18] tooltip:NSLocalizedString(@"Favicon", nil)] placeIn:self xRight:0 yTop:1.5];
-	self.warningButton = [[[[NSView buttonIcon:NSImageNameCaution size:18] action:@selector(didClickWarningButton:) target:nil] // up the responder chain
+	self.warningButton = [[[[NSView buttonIcon:NSImageNameCaution size:18]
+							action:@selector(didClickWarningButton:) target:nil] // up the responder chain
 						   tooltip:NSLocalizedString(@"Click here to show failure reason", nil)]
 						  placeIn:self xRight:0 yTop:1.5];
 	// 2. row
@@ -34,6 +36,10 @@
 	// 3. row
 	self.refreshNum = [[NSView inputField:@"30" width:85] placeIn:self x:x yTop:2*rowHeight];
 	self.refreshUnit = [[NSView popupButton:120] placeIn:self x:NSMaxX(self.refreshNum.frame) + PAD_M yTop:2*rowHeight];
+	self.regexConverterButton = [[[[NSView buttonIcon:RSSImageRegexIcon size:19]
+								   action:@selector(openRegexConverter) target:controller]
+								  tooltip:NSLocalizedString(@"Regex converter", nil)]
+								 placeIn:self xRight:0 yTop:2*rowHeight + 1];
 	
 	// initial state
 	self.url.accessibilityLabel = lbls[0];
@@ -41,6 +47,7 @@
 	self.refreshNum.accessibilityLabel = NSLocalizedString(@"Refresh interval", nil);
 	self.url.delegate = controller;
 	self.warningButton.hidden = YES;
+	self.regexConverterButton.hidden = YES;
 	self.refreshNum.formatter = [StrictUIntFormatter new]; // see below ...
 	[self prepareWarningPopover];
 	return self;

baRSS/Regex Editor/RegexConverterController.h

@@ -0,0 +1,12 @@
+@import Cocoa;
+@class RegexConverter, RegexConverterModal, Feed;
+
+NS_ASSUME_NONNULL_BEGIN
+
+@interface RegexConverterController : NSViewController <NSTextFieldDelegate>
++ (instancetype)withData:(NSData *)data andConverter:(nullable RegexConverter*)converter;
+- (RegexConverterModal*)getModalSheet;
+- (void)applyChanges:(Feed *)feed;
+@end
+
+NS_ASSUME_NONNULL_END

baRSS/Regex Editor/RegexConverterController.m

@@ -0,0 +1,125 @@
+#import "RegexConverterController.h"
+#import "RegexConverterView.h"
+#import "RegexConverter+Ext.h"
+#import "RegexConverterModal.h"
+#import "RegexFeed.h"
+#import "Feed+Ext.h"
+#import "NSURLRequest+Ext.h"
+
+
+// ################################################################
+// #
+// #  MARK: - RegexConverterController -
+// #
+// ################################################################
+
+@interface RegexConverterController() <NSWindowDelegate>
+@property (strong) RegexConverter *converter;
+@property (strong) RegexConverterModal *modalSheet;
+@property (strong) IBOutlet RegexConverterView *view; // override
+
+@property (strong) NSString *theData; // not "copy" because generated in initializer
+@end
+
+@implementation RegexConverterController
+@dynamic view;
+
+/// Dedicated initializer
++ (instancetype)withData:(NSData *)data andConverter:(RegexConverter*)converter {
+	RegexConverterController *diag = [self new];
+	diag.theData = data ? [[NSString alloc] initWithData:data encoding:NSUTF8StringEncoding]: @"";
+	diag.converter = converter;
+	return diag;
+}
+
+- (RegexConverterModal *)getModalSheet {
+	if (!self.modalSheet) {
+		self.modalSheet = [[RegexConverterModal alloc] initWithView:self.view];
+		self.modalSheet.delegate = self;
+	}
+	return self.modalSheet;
+}
+
+- (void)loadView {
+	self.view = [[RegexConverterView alloc] initWithController:self];
+	[self populateTextFields:self.converter];
+	[self updateOutput:self.theData];
+}
+
+/// Pre-fill UI control field values with @c RegexConverter properties.
+- (void)populateTextFields:(RegexConverter*)converter {
+	if (converter) {
+		self.view.entry.objectValue = converter.entry;
+		self.view.href.objectValue = converter.href;
+		self.view.title.objectValue = converter.title;
+		self.view.desc.objectValue = converter.desc;
+		self.view.date.objectValue = converter.date;
+		self.view.dateFormat.objectValue = converter.dateFormat;
+	}
+}
+
+#pragma mark - Update CoreData
+
+- (void)applyChanges:(Feed *)feed {
+	BOOL shouldDelete = self.view.entry.stringValue.length == 0;
+	
+	if (shouldDelete) {
+		if (feed.regex) {
+			[feed.managedObjectContext deleteObject:feed.regex];
+		}
+		return;
+	}
+	
+	if (!feed.regex) {
+		feed.regex = [RegexConverter newInContext:feed.managedObjectContext];
+	}
+	
+	[feed.regex setEntryIfChanged:self.view.entry.stringValue];
+	[feed.regex setHrefIfChanged:self.view.href.stringValue];
+	[feed.regex setTitleIfChanged:self.view.title.stringValue];
+	[feed.regex setDescIfChanged:self.view.desc.stringValue];
+	[feed.regex setDateIfChanged:self.view.date.stringValue];
+	[feed.regex setDateFormatIfChanged:self.view.dateFormat.stringValue];
+}
+
+#pragma mark - NSTextField Delegate
+
+- (RegexFeed*)regexParser {
+	RegexFeed *tmp = [RegexFeed new];
+	tmp.rxEntry = self.view.entry.stringValue;
+	tmp.rxHref = self.view.href.stringValue;
+	tmp.rxTitle = self.view.title.stringValue;
+	tmp.rxDesc = self.view.desc.stringValue;
+	tmp.rxDate = self.view.date.stringValue;
+	tmp.dateFormat = self.view.dateFormat.stringValue;
+	return tmp;
+}
+
+- (void)controlTextDidEndEditing:(NSNotification*)obj {
+	if (self.view.entry.stringValue.length == 0) {
+		[self updateOutput:self.theData];
+		return;
+	}
+	
+	NSError *err = nil;
+	NSArray<RegexFeedEntry*> *matches = [[self regexParser] process:self.theData error:&err];
+	if (err) {
+		[self updateOutput:[NSString stringWithFormat:@"%@\n––––\n%@",
+							err.localizedDescription, err.localizedRecoverySuggestion]];
+		return;
+	}
+	
+	NSMutableString *rv = [NSMutableString new];
+	for (RegexFeedEntry *entry in matches) {
+		[rv appendFormat:@"%@\n\n$_href: %@\n$_title: %@\n$_date: %@ -> %@\n$_description: %@\n\n----------\n\n",
+		 entry.rawMatch, entry.href, entry.title, entry.dateString, entry.date, entry.desc];
+	}
+	
+	[self updateOutput:rv];
+}
+
+- (void)updateOutput:(NSString *)text {
+	[self.view.output.textStorage setAttributedString:[[NSAttributedString alloc] initWithString:text]];
+}
+
+@end

baRSS/Regex Editor/RegexConverterModal.h

@@ -0,0 +1,12 @@
+@import Cocoa;
+
+NS_ASSUME_NONNULL_BEGIN
+
+@interface RegexConverterModal : NSPanel
+@property (readonly) BOOL didTapCancel;
+
+- (instancetype)initWithContentRect:(NSRect)contentRect styleMask:(NSWindowStyleMask)style backing:(NSBackingStoreType)backingStoreType defer:(BOOL)flag NS_UNAVAILABLE;
+- (instancetype)initWithView:(NSView*)content NS_DESIGNATED_INITIALIZER;
+@end
+
+NS_ASSUME_NONNULL_END

baRSS/Regex Editor/RegexConverterModal.m

@@ -0,0 +1,60 @@
+#import "RegexConverterModal.h"
+#import "UserPrefs.h"
+#import "NSView+Ext.h"
+
+@interface RegexConverterModal()
+@property (assign) BOOL respondToShouldClose;
+@end
+
+@implementation RegexConverterModal
+
+/// Designated initializer. 'Done' and 'Cancel' buttons will be added automatically.
+- (instancetype)initWithView:(NSView*)content {
+	static CGFloat const contentOffsetY = PAD_WIN + HEIGHT_BUTTON + PAD_L;
+
+	CGSize sz = content.frame.size;
+	sz.width += 2 * (NSInteger)PAD_WIN;
+	sz.height += PAD_WIN + contentOffsetY; // the second PAD_WIN is already in contentOffsetY
+
+	NSWindowStyleMask style = NSWindowStyleMaskTitled | NSWindowStyleMaskResizable | NSWindowStyleMaskFullSizeContentView;
+	self = [super initWithContentRect:NSMakeRect(0, 0, sz.width, sz.height) styleMask:style backing:NSBackingStoreBuffered defer:NO];
+	[content placeIn:self.contentView x:PAD_WIN y:contentOffsetY];
+
+	self.minSize = sz;
+
+	// Add default interaction buttons
+	NSButton *btnDone = [self createButton:NSLocalizedString(@"Done", nil) atX:PAD_WIN];
+	NSButton *btnCancel = [self createButton:NSLocalizedString(@"Cancel", nil) atX:sz.width - NSMinX(btnDone.frame) + PAD_M];
+	btnDone.tag = 42; // mark 'Done' button
+	//btnDone.keyEquivalent = @"\r"; // Enter / Return
+	btnCancel.keyEquivalent = [NSString stringWithFormat:@"%c", 0x1b]; // ESC
+	return self;
+}
+
+/// Helper method to create bottom-right aligned button.
+- (NSButton*)createButton:(NSString*)text atX:(CGFloat)x {
+	return [[[NSView button:text] action:@selector(didTapButton:) target:self] placeIn:self.contentView xRight:x y:PAD_WIN];
+}
+
+/// Sets bool for future usage
+- (void)setDelegate:(id<NSWindowDelegate>)delegate {
+	[super setDelegate:delegate];
+	self.respondToShouldClose = [delegate respondsToSelector:@selector(windowShouldClose:)];
+}
+
+/**
+ Called after user has clicked the 'Done' (Return) or 'Cancel' (Esc) button.
+ In the later case set @c .didTapCancel @c = @c YES
+ */
+- (void)didTapButton:(NSButton*)sender {
+	BOOL successful = (sender.tag == 42); // 'Done' button
+	_didTapCancel = !successful;
+	if (self.respondToShouldClose && ![self.delegate windowShouldClose:self]) {
+		return;
+	}
+	// Remove subviews to avoid _NSKeyboardFocusClipView issues
+	[self.contentView.subviews makeObjectsPerformSelector:@selector(removeFromSuperview)];
+	[self.sheetParent endSheet:self returnCode:(successful ? NSModalResponseOK : NSModalResponseCancel)];
+}
+
+@end

baRSS/Regex Editor/RegexConverterView.h

@@ -0,0 +1,20 @@
+@import Cocoa;
+@class RegexConverter, RegexConverterController;
+
+NS_ASSUME_NONNULL_BEGIN
+
+@interface RegexConverterView : NSView
+@property (strong) IBOutlet NSTextField *entry;
+@property (strong) IBOutlet NSTextField *href;
+@property (strong) IBOutlet NSTextField *title;
+@property (strong) IBOutlet NSTextField *date;
+@property (strong) IBOutlet NSTextField *dateFormat;
+@property (strong) IBOutlet NSTextField *desc;
+@property (strong) IBOutlet NSTextView *output;
+
+- (instancetype)initWithController:(RegexConverterController*)controller NS_DESIGNATED_INITIALIZER;
+- (instancetype)initWithFrame:(NSRect)frameRect NS_UNAVAILABLE;
+- (nullable instancetype)initWithCoder:(NSCoder *)decoder NS_UNAVAILABLE;
+@end
+
+NS_ASSUME_NONNULL_END

baRSS/Regex Editor/RegexConverterView.m

@@ -0,0 +1,141 @@
+#import "RegexConverterView.h"
+#import "RegexConverterController.h"
+#import "RegexConverter+Ext.h"
+#import "NSDate+Ext.h"
+#import "NSView+Ext.h"
+
+@interface RegexConverterView()
+@property NSPopover *infoPopover;
+@property (strong) IBOutlet NSTextField *popoverText;
+@property (strong) IBOutlet NSButton *infoButtonEntry;
+@end
+
+
+@implementation RegexConverterView
+
+static CGFloat const heightHowTo = 2 * HEIGHT_LABEL_SMALL;
+static CGFloat const heightOutput = 150;
+static CGFloat const heightRow = PAD_S + HEIGHT_INPUTFIELD;
+
+- (instancetype)initWithController:(RegexConverterController*)controller {
+	NSArray *lbls = @[
+		NSLocalizedString(@"Entries", nil),
+		NSLocalizedString(@"Link", nil),
+		NSLocalizedString(@"Title", nil),
+		NSLocalizedString(@"Description", nil),
+		NSLocalizedString(@"Date", nil),
+		NSLocalizedString(@"Date Format", nil),
+	];
+	NSView *labels = [NSView labelColumn:lbls rowHeight:HEIGHT_INPUTFIELD padding:PAD_S];
+	
+	self = [super initWithFrame:NSMakeRect(0, 0, 420, heightHowTo + PAD_L + NSHeight(labels.frame) + PAD_L + heightOutput)];
+	self.autoresizingMask = NSViewWidthSizable | NSViewHeightSizable;
+	
+	[self makeHowTo];
+	
+	CGFloat x = NSWidth(labels.frame) + PAD_S;
+	[labels placeIn:self x:0 yTop:heightHowTo + PAD_L];
+	
+	self.entry = [self inputAndExamples:0 x:x delegate:controller];
+	self.href = [self inputAndExamples:1 x:x delegate:controller];
+	self.title = [self inputAndExamples:2 x:x delegate:controller];
+	self.desc = [self inputAndExamples:3 x:x delegate:controller];
+	self.date = [self inputAndExamples:4 x:x delegate:controller];
+	self.dateFormat = [self inputAndExamples:5 x:x delegate:controller];
+	
+	// output text field
+	self.output = [self makeOutput];
+	
+	// prepare info popover
+	self.infoPopover = [NSView popover: NSMakeSize(400, 100)];
+	NSView *content = self.infoPopover.contentViewController.view;
+	self.popoverText = [[[[[NSView label:@""] selectable] sizableWidthAndHeight]
+						 multiline:NSMakeSize(384, 92)] placeIn:content x:8 y:4];
+	return self;
+}
+
+- (NSTextView *)makeHowTo {
+	NSTextView *tv = [[NSTextView new] sizableWidthAndHeight];
+	tv.editable = NO; // but selectable
+	tv.drawsBackground = NO;
+	tv.textContainer.textView.string = NSLocalizedString(@"DIY regex converter. Press enter to confirm. For help, refer to online tools (e.g., regex101 with options: global + single-line)", nil);
+	NSScrollView *scroll = [self wrapContent:tv inScrollView:NSMakeRect(-1, NSHeight(self.frame) - heightHowTo, NSWidth(self.frame) + 2, heightHowTo)];
+	scroll.drawsBackground = NO;
+	scroll.borderType = NSNoBorder;
+	scroll.verticalScrollElasticity = NSScrollElasticityNone;
+	scroll.autoresizingMask = NSViewMinYMargin | NSViewWidthSizable;
+	return tv;
+}
+
+- (NSTextView *)makeOutput {
+	NSTextView *tv = [[NSTextView new] sizableWidthAndHeight];
+	tv.editable = NO; // but selectable
+	tv.backgroundColor = NSColor.whiteColor;
+	[self wrapContent:tv inScrollView:NSMakeRect(-1, 0, NSWidth(self.frame) + 2, heightOutput)];
+	return tv;
+}
+
+/// Helper method to create input field with help button showing regex examples
+- (NSTextField *)inputAndExamples:(NSInteger)row x:(CGFloat)x delegate:(id<NSTextFieldDelegate>)delegate {
+	CGFloat yOffset = heightHowTo + PAD_L + row * heightRow;
+	NSTextField *input = [[[NSView inputField:@"" width:0] placeIn:self x:x yTop:yOffset]
+						  sizeToRight:PAD_S + HEIGHT_BUTTON]; // width of the helpButton
+	input.delegate = delegate;
+	
+	NSInteger tag = 700 + row;
+	NSArray<NSString *> *examples = [self examplesFor:tag];
+	if (examples.count > 0) {
+		[[[[NSView helpButton] action:@selector(didClickExamplesButton:) target:self]
+		  tooltip:NSLocalizedString(@"Click here to show examples", nil)]
+		 placeIn:self xRight:0 yTop:yOffset].tag = tag;
+		
+		input.placeholderString = [examples firstObject];
+	}
+	return input;
+}
+
+/// Example to be displayed in help button
+- (NSArray<NSString *> *)examplesFor:(NSInteger)tag {
+	switch (tag) {
+		case 700: return @[ // entries
+			@"<dt[ >].*?<\\/dd>",
+		];
+		case 701: return @[ // link
+			@"href=\"([^\"]*)\"",
+		];
+		case 702: return @[ // title
+			@"title=\"([^\"]*)\"",
+			@">([^\\s<]*?)<\\/span>"
+		];
+		case 703: return @[ // description
+			@"<dd[^>]*>(.*?)<\\/dd>",
+		];
+		case 704: return @[ // date matcher
+			@"(\\d{2}.\\d{2}.\\d{4})",
+		];
+		case 705: return @[ // date format
+			@"dd.MM.yyyy",
+			@"dd. MMM yyyy",
+			@"yyyy-MM-dd'T'HH:mm:ssZZZZZ",
+		];
+		default: break;
+	}
+	return @[];
+}
+
+- (void)didClickExamplesButton:(NSButton*)sender {
+	NSString *examples = [[self examplesFor:sender.tag] componentsJoinedByString:@"\n"];
+	
+	// TODO: clickable entries
+	self.popoverText.stringValue = [NSString stringWithFormat:@"%@", examples];
+	
+	NSSize newSize = self.popoverText.fittingSize; // width is limited by the textfield's preferred width
+	newSize.width += 2 * self.popoverText.frame.origin.x; // the padding
+	newSize.height += 2 * self.popoverText.frame.origin.y;
+	
+	// apply fitting size and display
+	self.infoPopover.contentSize = newSize;
+	[self.infoPopover showRelativeToRect:NSZeroRect ofView:sender preferredEdge:NSRectEdgeMinY];
+}
+
+@end

baRSS/Regex Editor/RegexFeed.h

@@ -0,0 +1,30 @@
+@import Cocoa;
+@class RegexConverter;
+
+NS_ASSUME_NONNULL_BEGIN
+
+@interface RegexFeedEntry : NSObject
+@property (nullable, readonly) NSString *href;
+@property (nullable, readonly) NSString *title;
+@property (nullable, readonly) NSString *desc;
+@property (nullable, readonly) NSString *dateString;
+@property (nullable, readonly) NSDate *date;
+
+@property (nullable, readonly) NSString *rawMatch;
+@end
+
+
+@interface RegexFeed : NSObject
+@property (nullable, copy) NSString *rxEntry;
+@property (nullable, copy) NSString *rxHref;
+@property (nullable, copy) NSString *rxTitle;
+@property (nullable, copy) NSString *rxDesc;
+@property (nullable, copy) NSString *rxDate;
+@property (nullable, copy) NSString *dateFormat;
+
++ (RegexFeed *)from:(RegexConverter*)regex;
+
+- (NSArray<RegexFeedEntry*>*)process:(NSString*)rawData error:(NSError * __autoreleasing *)err;
+@end
+
+NS_ASSUME_NONNULL_END

baRSS/Regex Editor/RegexFeed.m

@@ -0,0 +1,86 @@
+#import "RegexFeed.h"
+#import "RegexConverter+Ext.h"
+
+@interface RegexFeedEntry()
+@property (nullable, copy) NSString *href;
+@property (nullable, copy) NSString *title;
+@property (nullable, copy) NSString *desc;
+@property (nullable, copy) NSString *dateString;
+@property (nullable, retain) NSDate *date;
+
+@property (nullable, copy) NSString *rawMatch;
+@end
+
+@implementation RegexFeedEntry
+@end
+
+
+@implementation RegexFeed
+
++ (RegexFeed *)from:(RegexConverter*)regex {
+	RegexFeed *x = [RegexFeed new];
+	x.rxEntry = regex.entry;
+	x.rxHref = regex.href;
+	x.rxTitle = regex.title;
+	x.rxDesc = regex.desc;
+	x.rxDate = regex.date;
+	x.dateFormat = regex.dateFormat;
+	return x;
+}
+
+- (NSArray<RegexFeedEntry*>*)process:(NSString*)rawData error:(NSError * __autoreleasing *)err {
+	NSRegularExpression *re_entries = [self regex:_rxEntry error:err];
+	if (!re_entries) {
+		return @[];
+	}
+	NSDateFormatter *dateFormatter = [NSDateFormatter new];
+	[dateFormatter setDateFormat:_dateFormat];
+	[dateFormatter setTimeZone:[NSTimeZone timeZoneWithName:@"UTC"]];
+	// TODO: we probably need to handle locale. Especially for "d. MMM" like "3. Dec"
+
+	NSMutableArray<RegexFeedEntry*> *rv = [NSMutableArray new];
+	NSRegularExpression *re4 = [self regex:_rxDate error:err];
+	NSRegularExpression *re3 = [self regex:_rxDesc error:err];
+	NSRegularExpression *re2 = [self regex:_rxTitle error:err];
+	NSRegularExpression *re1 = [self regex:_rxHref error:err];
+	NSArray<NSTextCheckingResult*> *matches = [re_entries matchesInString:rawData options:0 range:NSMakeRange(0, rawData.length)];
+	
+	for (NSTextCheckingResult *match in matches) {
+		NSString *subdata = [rawData substringWithRange:match.range];
+		RegexFeedEntry *entry = [[RegexFeedEntry alloc] init];
+		entry.rawMatch = subdata;
+		entry.href = [self firstMatch:subdata re:re1];
+		entry.title = [self firstMatch:subdata re:re2];
+		entry.desc = [self firstMatch:subdata re:re3];
+		entry.dateString = [self firstMatch:subdata re:re4];
+		entry.date = (_dateFormat.length && entry.dateString.length) ? [dateFormatter dateFromString:entry.dateString] : nil;
+		[rv addObject:entry];
+	};
+	return rv;
+}
+
+- (nullable NSRegularExpression*)regex:(NSString*)pattern error:(NSError * __autoreleasing *)err {
+	if (pattern.length == 0) {
+		return nil;
+	}
+	NSRegularExpression *re = [[NSRegularExpression alloc] initWithPattern:pattern options:NSRegularExpressionDotMatchesLineSeparators error:err];
+	if (*err) {
+		return nil;
+	}
+	return re;
+}
+
+- (nonnull NSString*)firstMatch:(NSString*)str re:(NSRegularExpression*)re {
+	NSTextCheckingResult *match = [[re matchesInString:str options:0 range:NSMakeRange(0, str.length)] firstObject];
+	if (match) {
+		if (match.numberOfRanges < 2) {
+			return NSLocalizedString(@"Regex error: Missing match-group? ('outer(.*?)text')", nil);
+		}else if (match.numberOfRanges > 2) {
+			return NSLocalizedString(@"Regex error: Multiple match-groups found", nil);
+		}
+		return [str substringWithRange:[match rangeAtIndex:1]];
+	}
+	return @"";
+}
+
+@end