GFM compatible alerts (#53)

README.md

@@ -67,67 +67,92 @@ Extensions can be used by adding them to the options.
 
 ```java
 Options options = new Options();
-options.addExtension(new NotificationExtension());
-String html = Marked.marked("! This is an info message", options);
-  // => <div class="notification_info"><p>This is an info message</p></div>
+options.addExtension(new GFMAlertExtension());
+String html = Marked.marked("> [!NOTE]\n> This is a note!", options);
 ```
 
-### Notification extension
+### GFMAlert extension
 
-The notification extension helps you to add information messages to your markdown content.
-Keep in mind, you still need the CSS to style the messages as desired.
+Support for github like [alerts](https://docs.github.com/en/get-started/writing-on-github/getting-started-with-writing-and-formatting-on-github/basic-writing-and-formatting-syntax#alerts).
 
-#### Info message
-```text
-! This is an info message
+For styling, some project-specific CSS is required. SVG icons are embedded but can be replaced by configuration.
+
+#### Usage
+
+```java
+Options options = new Options();
+// Override default title for note alert
+GFMAlertOptions alertOptions = new GFMAlertOptions();
+alertOptions.setTitle(GFMAlerts.Alert.WARNING, "Attention!!!");
+GFMAlertExtension gfmAlerts = new GFMAlertExtension(alertOptions);
+options.addExtension(gfmAlerts);
+String html = Marked.marked("> [!NOTE]\n> This is a note!", options);
 ```
+
+#### Supported alert types
+
+**Note**
+```markdown
+> [!NOTE]
+> Useful information that users should know, even when skimming content.
+```
+**Note HTML**
 ```html
-<div class="notification_info">
-  <p>This is an info message</p>
+<div class="markdown-alert markdown-alert-note">
+	<p class="markdown-alert-title">Note</p>
+	<p>Useful information that users should know, even when skimming content.</p>
 </div>
 ```
 
-#### Success message
-```text
-!v This is a success message
+**Tip**
+```markdown
+> [!TIP]
+> Helpful advice for doing things better or more easily.
 ```
+**Tip HTML**
 ```html
-<div class="notification_success">
-  <p>This is a success message</p>
+<div class="markdown-alert markdown-alert-tip">
+	<p class="markdown-alert-title">Tip</p>
+	<p>Helpful advice for doing things better or more easily.</p>
 </div>
 ```
 
-#### Warning message
-```text
-!! This is a warning message
+**Important**
+```markdown
+> [!IMPORTANT]
+> Key information users need to know to achieve their goal.
 ```
+**Important HTML**
 ```html
-<div class="notification_warning">
-  <p>This is a warning message</p>
+<div class="markdown-alert markdown-alert-important">
+	<p class="markdown-alert-title">Important</p>
+	<p>Key information users need to know to achieve their goal.</p>
 </div>
 ```
 
-#### Error message
-```text
-!x  This is an error message
+**Warning**
+```markdown
+> [!WARNING]
+> Urgent info that needs immediate user attention to avoid problems.
 ```
+**Warning HTML**
 ```html
-<div class="notification_error">
-  <p>This is an error message</p>
+<div class="markdown-alert markdown-alert-warning">
+	<p class="markdown-alert-title">Warning</p>
+	<p>Urgent info that needs immediate user attention to avoid problems.</p>
 </div>
 ```
 
-#### Multiline notifications
-Notifications can span multiple lines.
-
-```text
-! This is an info message
-! That spans over several lines
+**Caution**
+```markdown
+> [!CAUTION]
+> Advises about risks or negative outcomes of certain actions.
 ```
+**Caution HTML**
 ```html
-<div class="notification_info">
-<p>This is an info message
-That spans over several lines</p>
+<div class="markdown-alert markdown-alert-caution">
+	<p class="markdown-alert-title">Caution</p>
+	<p>Advises about risks or negative outcomes of certain actions.</p>
 </div>
 ```
 

src/main/java/io/github/gitbucket/markedj/Lexer.java

@@ -159,18 +159,6 @@ protected void token(String src, boolean top, boolean bq, LexerContext context){
                 }
             }
 
-            // blockquote
-            {
-                List<String> cap = rules.get("blockquote").exec(src);
-                if(!cap.isEmpty()){
-                    src = src.substring(cap.get(0).length());
-                    context.pushToken(new BlockquoteStartToken());
-                    token(cap.get(0).replaceAll("(?m)^ *> ?", ""), top, true, context);
-                    context.pushToken(new BlockquoteEndToken());
-                    continue;
-                }
-            }
-
 			{
 				Extension.LexResult result = null;
 				for (Extension extension : options.getExtensions()) {
@@ -185,6 +173,18 @@ protected void token(String src, boolean top, boolean bq, LexerContext context){
 				}
 			}
 
+            // blockquote
+            {
+                List<String> cap = rules.get("blockquote").exec(src);
+                if(!cap.isEmpty()){
+                    src = src.substring(cap.get(0).length());
+                    context.pushToken(new BlockquoteStartToken());
+                    token(cap.get(0).replaceAll("(?m)^ *> ?", ""), top, true, context);
+                    context.pushToken(new BlockquoteEndToken());
+                    continue;
+                }
+            }
+
             // list
             {
                 List<String> cap = rules.get("list").exec(src);

src/main/java/io/github/gitbucket/markedj/Options.java

@@ -19,7 +19,7 @@ public class Options {
                                 "colgroup", "dd", "div", "dl", "dt", "em", "h1", "h2", "h3", "h4", "h5", "h6",
                                 "i", "img", "li", "ol", "p", "pre", "q", "small", "span", "strike", "strong",
                                 "sub", "sup", "table", "tbody", "td", "tfoot", "th", "thead", "tr", "u",
-                                "ul", "input", "del", "hr")
+                                "ul", "input", "del", "hr", "svg", "path")
                 .addAttributes("a", "href", "title")
                 .addProtocols("a", "href", "http", "https", "mailto", "ftp", "#")
                 .addAttributes("blockquote", "cite")
@@ -34,7 +34,10 @@ public class Options {
                 .addAttributes("th", "abbr", "axis", "colspan", "rowspan", "scope", "width")
                 .addAttributes("ul", "type")
                 .addAttributes("input", "type", "checked", "name", "value", "disabled")
-                .addAttributes(":all", "id", "class", "style");
+				.addAttributes("svg", "class", "viewBox", "version",  "width", "height", "aria-hidden")
+				.addAttributes("path", "d")
+                .addAttributes(":all", "id", "class", "style")
+			;
 
 	private List<Extension> extensions = new ArrayList<>();
 

src/main/java/io/github/gitbucket/markedj/extension/gfm/alert/DefaultGFMAlertRenderer.java

@@ -0,0 +1,39 @@
+/*
+ * Copyright 2024 GitBucket.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package io.github.gitbucket.markedj.extension.gfm.alert;
+
+import java.util.Locale;
+
+/**
+ *
+ * @author t.marx
+ */
+public class DefaultGFMAlertRenderer implements GFMAlertRenderer {
+
+	@Override
+	public String render(GFMAlertOptions options, String message, GFMAlerts.Alert alert) {
+		if (!message.startsWith("<p>")) {
+			message = String.format("<p>%s</p>", message);
+		}
+
+        return String.format("<div class=\"markdown-alert markdown-alert-%s\"><p class=\"markdown-alert-title\">%s</p>\n%s</div>", 
+				alert.name().toLowerCase(Locale.ENGLISH), 
+				options.getTitle(alert),
+				message
+		);
+	}
+
+}

src/main/java/io/github/gitbucket/markedj/extension/notification/NotificationEndToken.java → src/main/java/io/github/gitbucket/markedj/extension/gfm/alert/GFMAlertEndToken.java

@@ -13,17 +13,20 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
-package io.github.gitbucket.markedj.extension.notification;
+package io.github.gitbucket.markedj.extension.gfm.alert;
 
 import io.github.gitbucket.markedj.token.Token;
 
 /**
  *
  * @author t.marx
  */
-public class NotificationEndToken implements Token {
+public class GFMAlertEndToken implements Token {
+
+	public static String TYPE = "GFMAlertEndToken";
+
     @Override
     public String getType() {
-        return "NotificationEndToken";
+        return TYPE;
     }
 }

src/main/java/io/github/gitbucket/markedj/extension/notification/NotificationExtension.java → src/main/java/io/github/gitbucket/markedj/extension/gfm/alert/GFMAlertExtension.java

@@ -13,7 +13,7 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */
-package io.github.gitbucket.markedj.extension.notification;
+package io.github.gitbucket.markedj.extension.gfm.alert;
 
 import io.github.gitbucket.markedj.Lexer;
 import io.github.gitbucket.markedj.Parser;
@@ -22,51 +22,60 @@
 import io.github.gitbucket.markedj.rule.FindFirstRule;
 import io.github.gitbucket.markedj.rule.Rule;
 import io.github.gitbucket.markedj.token.Token;
+import java.util.HashMap;
 import java.util.List;
 import java.util.Locale;
+import java.util.Map;
 import java.util.function.Function;
-import java.util.regex.Matcher;
-import java.util.regex.Pattern;
 
 /**
  *
  * @author t.marx
  */
-public class NotificationExtension implements Extension {
+public class GFMAlertExtension implements Extension {
 
-	public static String BLOCK_NOTIFICATION = "^((?:(!([xv!]?))[^\n]*(?!^!)\n?)+)";
+	public static String EXPRESSION = "(?s)(?m)\\A^> \\[!(NOTE|TIP|IMPORTANT|WARNING|CAUTION)\\](.+?)(^\n|\\Z)";
 
-	private Rule notificationRule() {
-		return new FindFirstRule(BLOCK_NOTIFICATION);
-	}
+	private static final Rule RULE = new FindFirstRule(EXPRESSION);	
+
+	private GFMAlertRenderer renderer = new DefaultGFMAlertRenderer();
+
+	private GFMAlertOptions options;
 
+	public GFMAlertExtension () {
+		this(new GFMAlertOptions());
+	}
+
+	public GFMAlertExtension (GFMAlertOptions options) {
+		this.options = options;
+	}
+
+	public void setRenderer (GFMAlertRenderer renderer) {
+		this.renderer = renderer;
+	}
+
+	public void setOptions (GFMAlertOptions options) {
+		this.options = options;
+	}
+
+
 	@Override
 	public LexResult lex(String source, final Lexer.LexerContext context, final TokenConsumer consumer) {
-		List<String> cap = notificationRule().exec(source);
+		List<String> cap = RULE.exec(source);
 		boolean tokenFound = false;
 		if (!cap.isEmpty()) {
 			// we have detected several contiguous lines of notifications
 			// ensure that all are of same kind
 			String allNotificationsLines = cap.get(0);
+
+			String content = cap.get(2);
+
+			content = content.replaceAll("(?m)^ *> ?", "");
 
-			// if other kind of notifications lines are detected
-			// let's split them so that they are handled separately
-			String findOtherLinesPattern = "(?m)^(!" + Notifications.exceptGivenNotificationClass(cap.get(3)) + " .*)";
-			Matcher otherLinesMatcher = Pattern.compile(findOtherLinesPattern).matcher(cap.get(1));
-
-			if (otherLinesMatcher.find()) {
-				String otherLinesSeparated = otherLinesMatcher.replaceAll("\n$1\n");
-
-				// change the source to parse
-				// replace all the notifications lines with separated notifications lines
-				// and reparse the string
-				source = otherLinesSeparated + source.substring(allNotificationsLines.length());
-			} else {
-				source = source.substring(allNotificationsLines.length());
-				context.pushToken(new NotificationStartToken(cap.get(3)));
-				consumer.token(allNotificationsLines.replaceAll("(?m)^" + cap.get(2) + "[ ]?", ""), false, false, context);
-				context.pushToken(new NotificationEndToken());
-			}
+			source = source.substring(allNotificationsLines.length());
+			context.pushToken(new GFMAlertStartToken(cap.get(1)));
+			consumer.token(content, false, false, context);
+			context.pushToken(new GFMAlertEndToken());
 
 			tokenFound = true;
 		}
@@ -75,24 +84,24 @@ public LexResult lex(String source, final Lexer.LexerContext context, final Toke
 
 	@Override
 	public boolean handlesToken(String token) {
-		return NotificationStartToken.TYPE.equals(token);
+		return GFMAlertStartToken.TYPE.equals(token);
 	}
 
 	@Override
 	public String parse(Parser.ParserContext context, Function<Parser.ParserContext, String> tok) {
-		NotificationStartToken t = (NotificationStartToken) context.currentToken();
+		GFMAlertStartToken t = (GFMAlertStartToken) context.currentToken();
 		StringBuilder body = new StringBuilder();
 		while (true) {
 			Token n = context.nextToken();
-			if (n == null || n.getType().equals("NotificationEndToken")) {
+			if (n == null || n.getType().equals(GFMAlertEndToken.TYPE)) {
 				break;
 			}
 			body.append(tok.apply(context));
 		}
 		return render(body.toString(), t.getNotification());
 	}
 
-	private String render(String info, Notifications.Notification notification) {
-        return String.format("<div class=\"notification_%s\">\n%s</div>\n", notification.name().toLowerCase(Locale.ENGLISH), info);
+	private String render(String message, GFMAlerts.Alert alert) {
+		return renderer.render(options, message, alert);
     }
 }