add support for list style position

Author: JacobWrenn

lib/html_parser.dart

@@ -253,35 +253,57 @@ class HtmlParser extends StatelessWidget {
         ),
       );
     } else if (tree.style?.display == Display.LIST_ITEM) {
+      List<Widget> children;
+      if (tree.style?.listStylePosition == ListStylePosition.OUTSIDE) {
+        children = [
+          PositionedDirectional(
+            width: 30, //TODO derive this from list padding.
+            start: 0,
+            child: Text('${newContext.style.markerContent}\t',
+                textAlign: TextAlign.right,
+                style: newContext.style.generateTextStyle()),
+          ),
+          Padding(
+            padding:
+                EdgeInsets.only(left: 30), //TODO derive this from list padding.
+            child: StyledText(
+              textSpan: TextSpan(
+                children: tree.children
+                        ?.map((tree) => parseTree(newContext, tree))
+                        ?.toList() ??
+                    [],
+                style: newContext.style.generateTextStyle(),
+              ),
+              style: newContext.style,
+            ),
+          )
+        ];
+      } else if (tree.style?.listStylePosition == ListStylePosition.INSIDE) {
+        children = [
+          Padding(
+            padding:
+                EdgeInsets.only(left: 30), //TODO derive this from list padding.
+            child: StyledText(
+              textSpan: TextSpan(
+                text: '${newContext.style.markerContent}\t',
+                children: tree.children
+                        ?.map((tree) => parseTree(newContext, tree))
+                        ?.toList() ??
+                    [],
+                style: newContext.style.generateTextStyle(),
+              ),
+              style: newContext.style,
+            ),
+          )
+        ];
+      }
       return WidgetSpan(
         child: ContainerSpan(
           newContext: newContext,
           style: tree.style,
           shrinkWrap: context.parser.shrinkWrap,
           child: Stack(
-            children: <Widget>[
-              PositionedDirectional(
-                width: 30, //TODO derive this from list padding.
-                start: 0,
-                child: Text('${newContext.style.markerContent}\t',
-                    textAlign: TextAlign.right,
-                    style: newContext.style.generateTextStyle()),
-              ),
-              Padding(
-                padding: EdgeInsets.only(
-                    left: 30), //TODO derive this from list padding.
-                child: StyledText(
-                  textSpan: TextSpan(
-                    children: tree.children
-                            ?.map((tree) => parseTree(newContext, tree))
-                            ?.toList() ??
-                        [],
-                    style: newContext.style.generateTextStyle(),
-                  ),
-                  style: newContext.style,
-                ),
-              )
-            ],
+            children: children,
           ),
         ),
       );

lib/style.dart

@@ -77,6 +77,12 @@ class Style {
   /// Default: ListStyleType.DISC
   ListStyleType listStyleType;
 
+  /// CSS attribute "`list-style-position`"
+  ///
+  /// Inherited: yes,
+  /// Default: ListStylePosition.OUTSIDE
+  ListStylePosition listStylePosition;
+
   /// CSS attribute "`padding`"
   ///
   /// Inherited: no,
@@ -172,6 +178,7 @@ class Style {
     this.height,
     this.letterSpacing,
     this.listStyleType,
+    this.listStylePosition,
     this.padding,
     this.margin,
     this.textAlign,
@@ -194,6 +201,9 @@ class Style {
         (display == Display.BLOCK || display == Display.LIST_ITEM)) {
       this.alignment = Alignment.centerLeft;
     }
+    if (this.listStylePosition == null && display == Display.LIST_ITEM) {
+      this.listStylePosition = ListStylePosition.OUTSIDE;
+    }
   }
 
   TextStyle generateTextStyle() {
@@ -239,6 +249,7 @@ class Style {
       height: other.height,
       letterSpacing: other.letterSpacing,
       listStyleType: other.listStyleType,
+      listStylePosition: other.listStylePosition,
       padding: other.padding,
       //TODO merge EdgeInsets
       margin: other.margin,
@@ -276,6 +287,7 @@ class Style {
       fontWeight: child.fontWeight ?? fontWeight,
       letterSpacing: child.letterSpacing ?? letterSpacing,
       listStyleType: child.listStyleType ?? listStyleType,
+      listStylePosition: child.listStylePosition ?? listStylePosition,
       textAlign: child.textAlign ?? textAlign,
       textShadow: child.textShadow ?? textShadow,
       whiteSpace: child.whiteSpace ?? whiteSpace,
@@ -296,6 +308,7 @@ class Style {
     double height,
     double letterSpacing,
     ListStyleType listStyleType,
+    ListStylePosition listStylePosition,
     EdgeInsets padding,
     EdgeInsets margin,
     TextAlign textAlign,
@@ -327,6 +340,7 @@ class Style {
       height: height ?? this.height,
       letterSpacing: letterSpacing ?? this.letterSpacing,
       listStyleType: listStyleType ?? this.listStyleType,
+      listStylePosition: listStylePosition ?? this.listStylePosition,
       padding: padding ?? this.padding,
       margin: margin ?? this.margin,
       textAlign: textAlign ?? this.textAlign,
@@ -406,6 +420,11 @@ enum ListStyleType {
   DECIMAL,
 }
 
+enum ListStylePosition {
+  OUTSIDE,
+  INSIDE,
+}
+
 enum VerticalAlign {
   BASELINE,
   SUB,