Release 0.6

Author: f3ath

CHANGELOG.md

@@ -4,6 +4,11 @@ All notable changes to this project will be documented in this file.
 The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
+## [0.6.0] - 2023-08-06
+### Changed
+- Bumped SDK to 3.0.0
+- Context interface
+
 ## [0.5.1] - 2023-02-14
 ### Added
 - Dart 3 support
@@ -79,6 +84,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 ### Added
 - Initial library version
 
+[0.6.0]: https://github.com/f3ath/marker/compare/0.5.1...0.6.0
 [0.5.1]: https://github.com/f3ath/marker/compare/0.5.0...0.5.1
 [0.5.0]: https://github.com/f3ath/marker/compare/0.4.0...0.5.0
 [0.4.0]: https://github.com/f3ath/marker/compare/0.3.0...0.4.0
@@ -91,4 +97,4 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 [0.1.0]: https://github.com/f3ath/marker/compare/0.0.4...0.1.0
 [0.0.4]: https://github.com/f3ath/marker/compare/0.0.3...0.0.4
 [0.0.3]: https://github.com/f3ath/marker/compare/0.0.2...0.0.3
-[0.0.2]: https://github.com/f3ath/marker/compare/0.0.1...0.0.2
+[0.0.2]: https://github.com/f3ath/marker/compare/0.0.1...0.0.2

lib/flavors.dart

@@ -4,7 +4,7 @@ import 'package:marker/src/flavors/original.dart';
 
 /// The original flavor.
 /// See https://daringfireball.net/projects/markdown/syntax
-final Map<String, Node Function()> original = {
+final original = <String, Node Function()>{
   'h1': () => Header(1),
   'h2': () => Header(2),
   'h3': () => Header(3),
@@ -27,7 +27,7 @@ final Map<String, Node Function()> original = {
 };
 
 /// The changelog flavor.
-final Map<String, Node Function()> changelog = {
+final changelog = <String, Node Function()>{
   ...original,
   'h2': () => Release(), // Release header is special
 };

lib/marker.dart

@@ -20,6 +20,8 @@ String render(Iterable<md.Node> nodes,
     node.accept(builder);
   }
   return (builder.root.render(context) +
-          context.references.join(context.lineBreak))
+          context.ref.entries
+              .map((e) => '[${e.key}]: ${e.value}')
+              .join(context.lineBreak))
       .trim();
 }

lib/src/ast/builder.dart

@@ -6,12 +6,10 @@ import 'package:marker/src/ast/node.dart';
 /// element in the parsed tree the [Node] producer returns a node of
 /// the rendering tree.
 class Builder implements md.NodeVisitor {
-  Builder(this.flavor) {
-    _stack.add(Node());
-  }
+  Builder(this.flavor);
 
   final Map<String, Node Function()> flavor;
-  final List<Node> _stack = [];
+  final _stack = [Node()];
 
   /// Contains the root of the rendering tree
   Node get root => _stack.last;
@@ -30,8 +28,7 @@ class Builder implements md.NodeVisitor {
 
   @override
   bool visitElementBefore(md.Element element) {
-    final tag = element.tag;
-    final node = flavor[tag]?.call() ?? Node();
+    final node = flavor[element.tag]?.call() ?? Node();
     node.attributes.addAll(element.attributes);
     _stack.add(node);
     return true;

lib/src/ast/context.dart

@@ -2,6 +2,9 @@
 class Context {
   Context(this.inlineImages, this.inlineLinks, {this.lineBreak = '\n'});
 
+  /// Returns the next generated id for images and links.
+  String nextId() => 'id${_id++}';
+
   /// Whether the images should be rendered inline (or as references)
   final bool inlineImages;
 
@@ -14,5 +17,8 @@ class Context {
   /// Accumulates references to images and links generated during rendering.
   /// When the rendering is done, these lines will be added to the bottom
   /// of the generated document.
-  final List<String> references = [];
+  final ref = <String, String>{};
+
+  /// Internal id generator.
+  int _id = 1;
 }

lib/src/ast/node.dart

@@ -5,16 +5,16 @@ import 'package:marker/src/ast/text.dart';
 /// The base rendering tree node.
 class Node implements Renderable {
   /// Node's children
-  final List<Renderable> children = [];
+  final children = <Renderable>[];
 
   /// Attributes are copied from the corresponding parsed tree
   /// during tree building.
-  final Map<String, String> attributes = {};
+  final attributes = <String, String>{};
 
   /// Renders all children and returns concatenated output.
   @override
   String render(Context context) =>
-      children.map((node) => node.render(context)).join();
+      children.map((it) => it.render(context)).join();
 
   /// Adds a child text node
   void addText(String text) {

lib/src/ast/text.dart

@@ -4,18 +4,23 @@ import 'package:marker/src/ast/renderable.dart';
 class Text implements Renderable {
   Text(this.text);
 
+  static final _header = RegExp(r'^#');
+  static final _orderedListItem = RegExp(r'^(\d+)\. ');
+  static final _specialChars = RegExp(r'[*_~|\[\]]');
+  static final _unorderedListItem = RegExp(r'^[+-] ');
+
   final String text;
 
   /// Escapes common markdown special characters if those could be
   /// misinterpreted.
   @override
-  String render(Context context) => text
+  String render(Context _) => text
       // dot after a number in the beginning of the string is a list item
-      .replaceAllMapped(RegExp(r'^(\d+)\. '), (m) => '${m[1]}\\. ')
+      .replaceAllMapped(_orderedListItem, (m) => '${m[1]}\\. ')
       // Special markdown chars: emphasis, strikethrough, table cell, links
-      .replaceAllMapped(RegExp(r'[*_~|\[\]]'), (m) => '\\${m[0]}')
+      .replaceAllMapped(_specialChars, (m) => '\\${m[0]}')
       // + and - in the beginning of the string is a list item
-      .replaceAllMapped(RegExp(r'^[+-] '), (m) => '\\${m[0]}')
+      .replaceAllMapped(_unorderedListItem, (m) => '\\${m[0]}')
       // # in the beginning of the string is a header
-      .replaceAllMapped(RegExp(r'^#'), (m) => '\\${m[0]}');
+      .replaceAllMapped(_header, (m) => '\\${m[0]}');
 }

lib/src/flavors/changelog.dart

@@ -20,12 +20,11 @@ class _Link implements Renderable {
 
   @override
   String render(Context context) {
-    final innerText =
-        '[${_link.children.map((e) => e.render(context)).join()}]';
+    final innerText = _link.children.map((e) => e.render(context)).join();
     var href = _link.attributes['href']!;
     final title = _link.attributes['title'];
     if (title != null) href += ' "$title"';
-    context.references.add('$innerText: $href');
-    return innerText;
+    context.ref[innerText] = href;
+    return '[$innerText]';
   }
 }

lib/src/flavors/original.dart

@@ -56,59 +56,56 @@ class OrderedList extends Node {
 class ListItem extends Node {
   @override
   String render(Context context) {
-    if (children.isNotEmpty) {
-      if (_isBlock(children.first)) {
-        return _renderBlockChildren(context);
-      }
+    if (children.isNotEmpty && _isBlock(children.first)) {
+      return _renderBlockChildren(context);
     }
     return children
-            .map((node) {
-              if (node is OrderedList || node is UnorderedList) {
-                // We have a sublist. It must be separated from the previous
-                // text node and from other block elements.
-                final indent = (node is UnorderedList) ? 2 : 4;
-                return context.lineBreak +
-                    node
-                        .render(context)
-                        .addLinePrefix(' ' * indent, context.lineBreak) +
-                    context.lineBreak;
-              }
-              return node.render(context);
-            })
+            .map((node) => switch (node) {
+                  OrderedList() ||
+                  UnorderedList() =>
+                    // We have a sublist. It must be separated from the previous
+                    // text node and from other block elements.
+                    context.lineBreak +
+                        node.render(context).addLinePrefix(
+                            ' ' * ((node is UnorderedList) ? 2 : 4),
+                            context.lineBreak) +
+                        context.lineBreak,
+                  _ => node.render(context)
+                })
             .join()
             .trim() +
         context.lineBreak;
   }
 
   String _renderBlockChildren(Context context) =>
       children
-          .map((node) {
-            if (node is BlockQuote) {
-              return node
-                  .render(context)
-                  .addLinePrefix(' ' * 4, context.lineBreak);
-            }
-            if (node is Pre) {
-              // A code block in a list gets 3 spaces
-              // despite the standard requiring 4.
-              // @see https://daringfireball.net/projects/markdown/syntax#list
-              // So we have to compensate here.
-              return node
-                  .render(context)
-                  .addLinePrefix(' ' * 3, context.lineBreak);
-            }
-            return ' ' * 4 + node.render(context).trim();
-          })
+          .map((node) => switch (node) {
+                BlockQuote() => node
+                    .render(context)
+                    .addLinePrefix(' ' * 4, context.lineBreak),
+                Pre() =>
+                  // A code block in a list gets 3 spaces
+                  // despite the standard requiring 4.
+                  // @see https://daringfireball.net/projects/markdown/syntax#list
+                  // So we have to compensate here.
+                  node
+                      .render(context)
+                      .addLinePrefix(' ' * 3, context.lineBreak),
+                _ => ' ' * 4 + node.render(context).trim()
+              })
           .join(context.lineBreak * 2)
           .trim() +
       context.lineBreak * 2;
 
-  bool _isBlock(node) =>
-      node is Header ||
-      node is Paragraph ||
-      node is BlockQuote ||
-      node is OrderedList ||
-      node is UnorderedList;
+  bool _isBlock(node) => switch (node) {
+        Header() ||
+        Paragraph() ||
+        BlockQuote() ||
+        OrderedList() ||
+        UnorderedList() =>
+          true,
+        _ => false
+      };
 }
 
 class Pre extends Node {}
@@ -122,20 +119,11 @@ class Code extends Node {
     if (text.contains(context.lineBreak)) {
       return text.addLinePrefix(' ' * 4, context.lineBreak);
     }
-    final fencing = _detectFencing(text);
-    return fencing + text + fencing;
+    return text.fenced('`');
   }
 
   @override
   void addText(String text) => _buf.write(text);
-
-  String _detectFencing(String text) {
-    var fencing = '';
-    do {
-      fencing += '`';
-    } while (text.contains(fencing));
-    return fencing;
-  }
 }
 
 class HorizontalRule extends Node {
@@ -157,46 +145,51 @@ class Link extends Node {
   String render(Context context) {
     final innerText = '[${super.render(context)}]';
     var href = attributes['href']!;
-    if (attributes.containsKey('title')) {
-      href += ' "${attributes['title']}"';
+    if (attributes case {'title': String title}) {
+      href += ' "$title"';
     }
-
     if (context.inlineLinks) {
       return '$innerText($href)';
     }
-    final id = '[id${_id++}]';
-    context.references.add('$id: $href');
-    return '$innerText$id';
+    final id = context.nextId();
+    context.ref[id] = href;
+    return '$innerText[$id]';
   }
 }
 
 class Image extends Node {
   @override
   String render(Context context) {
     var src = attributes['src']!;
-    if (attributes.containsKey('title')) {
-      src += ' "${attributes['title']}"';
+    if (attributes case {'title': String title}) {
+      src += ' "$title"';
     }
     final alt = attributes['alt'] ?? '';
     if (context.inlineImages) {
       return '![$alt]($src)';
     }
-    final id = '[id${_id++}]';
-    context.references.add('$id: $src');
-    return '![$alt]$id';
+    final id = context.nextId();
+    context.ref[id] = src;
+    return '![$alt][$id]';
   }
 }
 
-int _id = 1; // id generator for images and links
-
 extension _StringExt on String {
   static const _splitter = LineSplitter();
 
   /// Adds [prefix] to all lines in the string.
   addLinePrefix(String prefix, String lineBreak, {bool trim = false}) =>
       _splitter
           .convert(this)
-          .map((_) => prefix + _)
-          .map((_) => trim ? _.trim() : _)
+          .map((it) => prefix + it)
+          .map((it) => trim ? it.trim() : it)
           .join(lineBreak);
+
+  String fenced(String block) {
+    var fence = '';
+    do {
+      fence += block;
+    } while (contains(fence));
+    return fence + this + fence;
+  }
 }

pubspec.yaml

@@ -1,6 +1,6 @@
 name: marker
 description: A renderer (printer) for the markdown library. Renders the parsed AST back into markdown.
-version: 0.5.1
+version: 0.6.0
 homepage: https://github.com/f3ath/marker
 
 cider:
@@ -9,7 +9,7 @@ cider:
     diff: https://github.com/f3ath/marker/compare/%from%...%to%
 
 environment:
-  sdk: '>=2.19.0 <4.0.0'
+  sdk: '>=3.0.0 <4.0.0'
 
 dependencies:
   markdown: ^7.0.0

test/original/list.md

@@ -42,4 +42,4 @@ sit amet velit.
         b = 2;
 
 
-123\. This is not a list item.
+123\. This is not a list item.