GFM compatible alerts

README.md

@@ -67,69 +67,76 @@ 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
-```
-```html
-<div class="notification_info">
-  <p>This is an info message</p>
-</div>
-```
-
-#### Success message
-```text
-!v This is a success message
-```
-```html
-<div class="notification_success">
-  <p>This is a success message</p>
-</div>
-```
-
-#### Warning message
-```text
-!! This is a warning message
-```
-```html
-<div class="notification_warning">
-  <p>This is a warning message</p>
-</div>
-```
+For styling, some project-specific CSS is required. SVG icons are embedded but can be replaced by configuration.
 
-#### Error message
-```text
-!x  This is an error message
-```
-```html
-<div class="notification_error">
-  <p>This is an error message</p>
-</div>
-```
+#### Usage
 
-#### Multiline notifications
-Notifications can span multiple lines.
+```java
+Options options = new Options();
+GFMAlertExtension gfmAlerts = new GFMAlertExtension();
+// Override default title for note alert
+gfmAlerts.addTitle(GFMAlerts.Alert.NOTE, "Notice");
+// Override default icon for note alert
+gfmAlerts.setIcon(GFMAlerts.Alert.NOTE, "");
+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**
+> [!NOTE]
+> Useful information that users should know, even when skimming content.
+
+**Tip**
+```markdown
+> [!TIP]
+> Helpful advice for doing things better or more easily.
+```
+**Note HTML**
+> [!TIP]
+> Helpful advice for doing things better or more easily.
+
+**Important**
+```markdown
+> [!IMPORTANT]
+> Key information users need to know to achieve their goal.
+```
+**Important HTML**
+> [!IMPORTANT]
+> Key information users need to know to achieve their goal.
+
+**Warning**
+```markdown
+> [!WARNING]
+> Urgent info that needs immediate user attention to avoid problems.
+```
+**Warning HTML**
+> [!WARNING]
+> Urgent info that needs immediate user attention to avoid problems.
+
+**Caution**
+```markdown
+> [!CAUTION]
+> Advises about risks or negative outcomes of certain actions.
+```
+**Caution HTML**
+> [!CAUTION]
+> Advises about risks or negative outcomes of certain actions.
 
-```text
-! This is an info message
-! That spans over several lines
-```
-```html
-<div class="notification_info">
-<p>This is an info message
-That spans over several lines</p>
-</div>
-```
 
 ## for Developers
 

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/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/gfm/alert/GFMAlertExtension.java

@@ -0,0 +1,136 @@
+/*
+ * Copyright 2023 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 io.github.gitbucket.markedj.Lexer;
+import io.github.gitbucket.markedj.Parser;
+import io.github.gitbucket.markedj.extension.Extension;
+import io.github.gitbucket.markedj.extension.TokenConsumer;
+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;
+
+/**
+ *
+ * @author t.marx
+ */
+public class GFMAlertExtension implements Extension {
+
+	public static String EXPRESSION = "(?s)(?m)\\A^> \\[!(NOTE|TIP|IMPORTANT|WARNING|CAUTION)\\](.+?)(^\n|\\Z)";
+
+	private static final Rule RULE = new FindFirstRule(EXPRESSION);
+
+	private final Map<GFMAlerts.Alert, String> titles = new HashMap<>();
+
+	private final Map<GFMAlerts.Alert, String> icons = new HashMap<>();
+
+	/**
+	 * Creates the extension with default titles and icons.
+	 */
+	public GFMAlertExtension () {
+		titles.put(GFMAlerts.Alert.TIP, "Tip");
+		titles.put(GFMAlerts.Alert.NOTE, "Note");
+		titles.put(GFMAlerts.Alert.IMPORTANT, "Important");
+		titles.put(GFMAlerts.Alert.WARNING, "Warning");
+		titles.put(GFMAlerts.Alert.CAUTION, "Caution");
+
+		icons.put(GFMAlerts.Alert.TIP, GFMAlerts.Icons.TIP);
+		icons.put(GFMAlerts.Alert.NOTE, GFMAlerts.Icons.NOTE);
+		icons.put(GFMAlerts.Alert.IMPORTANT, GFMAlerts.Icons.IMPORTANT);
+		icons.put(GFMAlerts.Alert.WARNING, GFMAlerts.Icons.WARNING);
+		icons.put(GFMAlerts.Alert.CAUTION, GFMAlerts.Icons.CAUTION);
+	}
+
+	/**
+	 * Adds the title for an alert.
+	 * 
+	 * @param alert
+	 * @param title 
+	 */
+	public void addTitle (final GFMAlerts.Alert alert, final String title ) {
+		titles.put(alert, title);
+	}
+
+	/**
+	 * Adds a avg icon for a alert.
+	 * @param alert
+	 * @param icon 
+	 */
+	public void addIcon (final GFMAlerts.Alert alert, final String icon ) {
+		icons.put(alert, icon);
+	}
+
+	@Override
+	public LexResult lex(String source, final Lexer.LexerContext context, final TokenConsumer consumer) {
+		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)^ *> ?", "");
+
+			source = source.substring(allNotificationsLines.length());
+			context.pushToken(new GFMAlertStartToken(cap.get(1)));
+			consumer.token(content, false, false, context);
+			context.pushToken(new GFMAlertEndToken());
+
+			tokenFound = true;
+		}
+		return new LexResult(source, tokenFound);
+	}
+
+	@Override
+	public boolean handlesToken(String token) {
+		return GFMAlertStartToken.TYPE.equals(token);
+	}
+
+	@Override
+	public String parse(Parser.ParserContext context, Function<Parser.ParserContext, String> tok) {
+		GFMAlertStartToken t = (GFMAlertStartToken) context.currentToken();
+		StringBuilder body = new StringBuilder();
+		while (true) {
+			Token n = context.nextToken();
+			if (n == null || n.getType().equals(GFMAlertEndToken.TYPE)) {
+				break;
+			}
+			body.append(tok.apply(context));
+		}
+		return render(body.toString(), t.getNotification());
+	}
+
+	private String render(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%s</p>\n%s</div>", 
+				alert.name().toLowerCase(Locale.ENGLISH), 
+				icons.get(alert),
+				titles.get(alert),
+				message
+		);
+    }
+}

src/main/java/io/github/gitbucket/markedj/extension/notification/NotificationStartToken.java → src/main/java/io/github/gitbucket/markedj/extension/gfm/alert/GFMAlertStartToken.java

@@ -13,29 +13,29 @@
  * 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 NotificationStartToken implements Token {
-	protected static String TYPE = "NotificationStartToken";
+public class GFMAlertStartToken implements Token {
+	protected static String TYPE = "GFMAlertStartToken";
 
-	private Notifications.Notification notification;
+	private GFMAlerts.Alert alert;
 
-    public NotificationStartToken(String type) {
-        this.notification = Notifications.Notification.fromString(type);
+    public GFMAlertStartToken(String type) {
+        this.alert = GFMAlerts.Alert.fromString(type);
     }
 
     @Override
     public String getType() {
         return TYPE;
     }
 
-    public Notifications.Notification getNotification() {
-        return notification;
+    public GFMAlerts.Alert getNotification() {
+        return alert;
     }
 }