migrate to null safe dart

CHANGELOG.md

@@ -1,5 +1,9 @@
 # CHANGELOG
 
+## 2.0.0
+
+* Support for null safe dart added.
+
 ## 1.0.0+1
 
 * Fixed regression where lookups from list did not work. Removed failing tests

analysis_options.yaml

@@ -1 +1,5 @@
-include: package:pedantic/analysis_options.yaml
+linter:
+  rules:
+    unawaited_futures: true
+    curly_braces_in_flow_control_structures: true
+    avoid_catches_without_on_clauses: true

lib/mustache.dart

@@ -11,10 +11,10 @@ abstract class Template {
       {bool lenient,
       bool htmlEscapeValues,
       String name,
-      PartialResolver partialResolver,
+      PartialResolver? partialResolver,
       String delimiters}) = t.Template.fromSource;
 
-  String get name;
+  String? get name;
   String get source;
 
   /// [values] can be a combination of Map, List, String. Any non-String object
@@ -28,7 +28,7 @@ abstract class Template {
   void render(values, StringSink sink);
 }
 
-typedef PartialResolver = Template Function(String);
+typedef PartialResolver = Template? Function(String);
 
 typedef LambdaFunction = Object Function(LambdaContext context);
 
@@ -39,7 +39,7 @@ abstract class LambdaContext {
   /// Render the current section tag in the current context and return the
   /// result as a string. If provided, value will be added to the top of the
   /// context's stack.
-  String renderString({Object value});
+  String renderString({Object? value});
 
   /// Render and directly output the current section tag. If provided, value
   /// will be added to the top of the context's stack.
@@ -54,10 +54,10 @@ abstract class LambdaContext {
 
   /// Evaluate the string as a mustache template using the current context. If
   /// provided, value will be added to the top of the context's stack.
-  String renderSource(String source, {Object value});
+  String renderSource(String source, {Object? value});
 
   /// Lookup the value of a variable in the current context.
-  Object lookup(String variableName);
+  Object? lookup(String variableName);
 }
 
 /// [TemplateException] is used to obtain the line and column numbers
@@ -68,7 +68,7 @@ abstract class TemplateException implements Exception {
 
   /// The name used to identify the template, as passed to the Template
   /// constructor.
-  String get templateName;
+  String? get templateName;
 
   /// The 1-based line number of the token where formatting error was found.
   int get line;
@@ -77,10 +77,10 @@ abstract class TemplateException implements Exception {
   int get column;
 
   /// The character offset within the template source.
-  int get offset;
+  int? get offset;
 
   /// The template source.
-  String get source;
+  String? get source;
 
   /// A short source substring of the source at the point the problem occurred
   /// with parsing or rendering.

lib/src/lambda_context.dart

@@ -27,7 +27,7 @@ class LambdaContext implements m.LambdaContext {
   }
 
   @override
-  String renderString({Object value}) {
+  String renderString({Object? value}) {
     _checkClosed();
     if (_node is! SectionNode) {
       _error(
@@ -38,15 +38,15 @@ class LambdaContext implements m.LambdaContext {
     return sink.toString();
   }
 
-  void _renderSubtree(StringSink sink, Object value) {
+  void _renderSubtree(StringSink sink, Object? value) {
     var renderer = Renderer.subtree(_renderer, sink);
-    SectionNode section = _node;
+    var section = _node as SectionNode;
     if (value != null) renderer.push(value);
     renderer.render(section.children);
   }
 
   @override
-  void render({Object value}) {
+  void render({Object? value}) {
     _checkClosed();
     if (_node is! SectionNode) {
       _error('LambdaContext.render() can only be called on section tags.');
@@ -66,10 +66,8 @@ class LambdaContext implements m.LambdaContext {
 
     if (_node is! SectionNode) return '';
 
-    SectionNode node = _node;
-
+    var node = _node as SectionNode;
     var nodes = node.children;
-
     if (nodes.isEmpty) return '';
 
     if (nodes.length == 1 && nodes.first is TextNode) {
@@ -80,14 +78,14 @@ class LambdaContext implements m.LambdaContext {
   }
 
   @override
-  String renderSource(String source, {Object value}) {
+  String renderSource(String source, {Object? value}) {
     _checkClosed();
     var sink = StringBuffer();
 
     // Lambdas used for sections should parse with the current delimiters.
     var delimiters = '{{ }}';
     if (_node is SectionNode) {
-      SectionNode node = _node;
+      var node = _node as SectionNode;
       delimiters = node.delimiters;
     }
 
@@ -104,7 +102,7 @@ class LambdaContext implements m.LambdaContext {
   }
 
   @override
-  Object lookup(String variableName) {
+  Object? lookup(String variableName) {
     _checkClosed();
     return _renderer.resolveValue(variableName);
   }

lib/src/node.dart

@@ -59,7 +59,7 @@ class SectionNode extends Node {
   final String delimiters;
   final bool inverse;
   final int contentStart;
-  int contentEnd; // Set in parser when close tag is parsed.
+  int? contentEnd; // Set in parser when close tag is parsed.
   final List<Node> children = <Node>[];
 
   @override

lib/src/parser.dart

@@ -4,7 +4,7 @@ import 'template_exception.dart';
 import 'token.dart';
 
 List<Node> parse(
-    String source, bool lenient, String templateName, String delimiters) {
+    String source, bool lenient, String? templateName, String delimiters) {
   var parser = Parser(source, templateName, delimiters, lenient: lenient);
   return parser.parse();
 }
@@ -33,7 +33,7 @@ class TagType {
 }
 
 class Parser {
-  Parser(String source, String templateName, String delimiters,
+  Parser(String source, String? templateName, String delimiters,
       {lenient = false})
       : _source = source,
         _templateName = templateName,
@@ -43,12 +43,12 @@ class Parser {
 
   final String _source;
   final bool _lenient;
-  final String _templateName;
+  final String? _templateName;
   final String _delimiters;
   final Scanner _scanner;
   final List<SectionNode> _stack = <SectionNode>[];
-  List<Token> _tokens;
-  String _currentDelimiters;
+  late List<Token> _tokens;
+  String? _currentDelimiters;
   int _offset = 0;
 
   List<Node> parse() {
@@ -83,7 +83,7 @@ class Parser {
           break;
 
         case TokenType.lineEnd:
-          _appendTextToken(_read());
+          _appendTextToken(_read()!);
           _parseLine();
           break;
 
@@ -101,11 +101,11 @@ class Parser {
   }
 
   // Returns null on EOF.
-  Token _peek() => _offset < _tokens.length ? _tokens[_offset] : null;
+  Token? _peek() => _offset < _tokens.length ? _tokens[_offset] : null;
 
   // Returns null on EOF.
-  Token _read() {
-    Token t;
+  Token? _read() {
+    Token? t;
     if (_offset < _tokens.length) {
       t = _tokens[_offset];
       _offset++;
@@ -122,7 +122,7 @@ class Parser {
     return token;
   }
 
-  Token _readIf(TokenType type, {eofOk = false}) {
+  Token? _readIf(TokenType type, {eofOk = false}) {
     var token = _peek();
     if (!eofOk && token == null) throw _errorEof();
     return token != null && token.type == type ? _read() : null;
@@ -151,14 +151,14 @@ class Parser {
 
   // Add the node to top most section on the stack. If a section node then
   // push it onto the stack, if a close section tag, then pop the stack.
-  void _appendTag(Tag tag, Node node) {
+  void _appendTag(Tag tag, Node? node) {
     switch (tag.type) {
 
       // {{#...}}  {{^...}}
       case TagType.openSection:
       case TagType.openInverseSection:
-        _stack.last.children.add(node);
-        _stack.add(node);
+        _stack.last.children.add(node!);
+        _stack.add(node as SectionNode);
         break;
 
       // {{/...}}
@@ -229,7 +229,7 @@ class Parser {
       ];
 
       if (tag != null &&
-          (_peek() == null || _peek().type == TokenType.lineEnd) &&
+          (_peek() == null || _peek()!.type == TokenType.lineEnd) &&
           standaloneTypes.contains(tag.type)) {
         // This is a tag on a "standalone line", so do not create text nodes
         // for whitespace, or the following newline.
@@ -259,7 +259,7 @@ class Parser {
 
   // If open delimiter, or change delimiter token then return a tag.
   // If EOF or any another token then return null.
-  Tag _readTag() {
+  Tag? _readTag() {
     var t = _peek();
     if (t == null ||
         (t.type != TokenType.changeDelimiter &&
@@ -284,7 +284,7 @@ class Parser {
     // A sigil is the character which identifies which sort of tag it is,
     // i.e.  '#', '/', or '>'.
     // Variable tags and triple mustache tags don't have a sigil.
-    TagType tagType;
+    TagType? tagType;
 
     if (open.value == '{{{') {
       tagType = TagType.tripleMustache;
@@ -328,21 +328,21 @@ class Parser {
 
     var close = _expect(TokenType.closeDelimiter);
 
-    return Tag(tagType, name, open.start, close.end);
+    return Tag(tagType!, name, open.start, close.end);
   }
 
-  Node _createNodeFromTag(Tag tag, {String partialIndent = ''}) {
+  Node? _createNodeFromTag(Tag? tag, {String partialIndent = ''}) {
     // Handle EOF case.
     if (tag == null) {
       return null;
     }
 
-    Node node;
+    Node? node;
     switch (tag.type) {
       case TagType.openSection:
       case TagType.openInverseSection:
         var inverse = tag.type == TagType.openInverseSection;
-        node = SectionNode(tag.name, tag.start, tag.end, _currentDelimiters,
+        node = SectionNode(tag.name, tag.start, tag.end, _currentDelimiters!,
             inverse: inverse);
         break;
 

lib/src/renderer.dart

@@ -36,8 +36,8 @@ class Renderer extends Visitor {
   final List _stack;
   final bool lenient;
   final bool htmlEscapeValues;
-  final m.PartialResolver partialResolver;
-  final String templateName;
+  final m.PartialResolver? partialResolver;
+  final String? templateName;
   final String indent;
   final String source;
 
@@ -48,7 +48,7 @@ class Renderer extends Visitor {
   void write(Object output) => sink.write(output.toString());
 
   void render(List<Node> nodes) {
-    if (indent == null || indent == '') {
+    if (indent == '') {
       nodes.forEach((n) => n.accept(this));
     } else if (nodes.isNotEmpty) {
       // Special case to make sure there is not an extra indent after the last
@@ -69,7 +69,7 @@ class Renderer extends Visitor {
   @override
   void visitText(TextNode node, {bool lastNode = false}) {
     if (node.text == '') return;
-    if (indent == null || indent == '') {
+    if (indent == '') {
       write(node.text);
     } else if (lastNode && node.text.runes.last == _NEWLINE) {
       // Don't indent after the last line in a template.
@@ -87,7 +87,7 @@ class Renderer extends Visitor {
 
     if (value is Function) {
       var context = LambdaContext(node, this);
-      Function valueFunction = value;
+      var valueFunction = value;
       value = valueFunction(context);
       context.close();
     }
@@ -101,7 +101,7 @@ class Renderer extends Visitor {
       var output = !node.escape || !htmlEscapeValues
           ? valueString
           : _htmlEscape(valueString);
-      if (output != null) write(output);
+      write(output);
     }
   }
 
@@ -188,8 +188,8 @@ class Renderer extends Visitor {
   @override
   void visitPartial(PartialNode node) {
     var partialName = node.name;
-    Template template =
-        partialResolver == null ? null : partialResolver(partialName);
+    var template =
+        partialResolver == null ? null : (partialResolver!(partialName) as Template?);
     if (template != null) {
       var renderer = Renderer.partial(this, template, node.indent);
       var nodes = getTemplateNodes(template);
@@ -203,7 +203,7 @@ class Renderer extends Visitor {
 
   // Walks up the stack looking for the variable.
   // Handles dotted names of the form "a.b.c".
-  Object resolveValue(String name) {
+  Object? resolveValue(String name) {
     if (name == '.') {
       return _stack.last;
     }
@@ -216,7 +216,7 @@ class Renderer extends Visitor {
       }
     }
     for (var i = 1; i < parts.length; i++) {
-      if (object == null || object == noSuchProperty) {
+      if (object == noSuchProperty) {
         return noSuchProperty;
       }
       object = _getNamedProperty(object, parts[i]);
@@ -232,9 +232,11 @@ class Renderer extends Visitor {
     if (object is Map && object.containsKey(name)) return object[name];
 
     if (object is List && _integerTag.hasMatch(name)) {
-      return object[int.parse(name)];
+      var index = int.parse(name);
+      if (object.length > index) {
+        return object[index];
+      }
     }
-
     return noSuchProperty;
   }