Mustachio: allow mlti-name section keys (#2494)

Author: srawlins

lib/src/mustachio/parser.dart

@@ -178,31 +178,50 @@ class MustachioParser {
   /// [_index] should be at the character immediately following the `#`
   /// character which opens a possible section tag.
   _TagParseResult _parseSection({@required invert}) {
-    var result = _parseKey();
-    if (result.type == _KeyParseResultType.notKey) {
+    var parsedKey = _parseKey();
+    if (parsedKey.type == _KeyParseResultType.notKey) {
       return _TagParseResult.notTag;
-    } else if (result == _KeyParseResult.endOfFile) {
+    } else if (parsedKey == _KeyParseResult.endOfFile) {
       return _TagParseResult.endOfFile;
     }
 
-    var children = _parseBlock(sectionKey: result.joinedNames);
+    var children = _parseBlock(sectionKey: parsedKey.joinedNames);
+
+    if (parsedKey.names.length > 1) {
+      // Desugar section with dots into nested sections.
+      //
+      // Given a multi-name section like
+      // `{{#one.two.three}}...{/one.two.three}}`, "one" must be a non-Iterable,
+      // non-bool value. "two" must also be a non-Iterable, non-bool value.
+      // "three" may be any kind of value, resulting in a repeated section,
+      // optional section, or value section. The [children], the parsed AST
+      // inside the section, are the children of the [three] section. The
+      // [three] section is the singular child node of the [two] section, and
+      // the [two] section is the singular child of the [one] section.
+      var section = Section([parsedKey.names.last], children, invert: invert);
+      for (var sectionKey in parsedKey.names.reversed.skip(1)) {
+        section = Section([sectionKey], [section], invert: false);
+      }
+      return _TagParseResult.ok(section);
+    }
 
-    return _TagParseResult.ok(Section(result.names, children, invert: invert));
+    return _TagParseResult.ok(
+        Section(parsedKey.names, children, invert: invert));
   }
 
   /// Tries to parse an end tag at [_index].
   ///
   /// [_index] should be at the character immediately following the `/`
   /// character which opens a possible end tag.
   _TagParseResult _parseEndSection() {
-    var result = _parseKey();
-    if (result.type == _KeyParseResultType.notKey) {
+    var parsedKey = _parseKey();
+    if (parsedKey.type == _KeyParseResultType.notKey) {
       return _TagParseResult.notTag;
-    } else if (result == _KeyParseResult.endOfFile) {
+    } else if (parsedKey == _KeyParseResult.endOfFile) {
       return _TagParseResult.endOfFile;
     }
 
-    return _TagParseResult.endTag(result.joinedNames);
+    return _TagParseResult.endTag(parsedKey.joinedNames);
   }
 
   /// Tries to parse a variable tag at [_index].
@@ -216,14 +235,14 @@ class MustachioParser {
       _index++;
       _walkPastWhitespace();
     }
-    var result = _parseKey(escape: escape);
-    if (result.type == _KeyParseResultType.notKey) {
+    var parsedKey = _parseKey(escape: escape);
+    if (parsedKey.type == _KeyParseResultType.notKey) {
       return _TagParseResult.notTag;
-    } else if (result == _KeyParseResult.endOfFile) {
+    } else if (parsedKey == _KeyParseResult.endOfFile) {
       return _TagParseResult.endOfFile;
     }
 
-    return _TagParseResult.ok(Variable(result.names, escape: escape));
+    return _TagParseResult.ok(Variable(parsedKey.names, escape: escape));
   }
 
   /// Tries to parse a key at [_index].

test/mustachio/parser_test.dart

@@ -227,6 +227,35 @@ void main() {
     _expectVariable(section.children.single, equals(['two']));
   });
 
+  test('parses section with multi-name key', () {
+    var parser =
+        MustachioParser('Text {{#one.two.three}}Text{{/one.two.three}}');
+    var ast = parser.parse();
+    expect(ast, hasLength(2));
+    _expectText(ast[0], equals('Text '));
+    var sectionOne = ast[1] as Section;
+    _expectSection(sectionOne, equals(['one']));
+    expect(sectionOne.children, hasLength(1));
+    var sectionTwo = sectionOne.children[0] as Section;
+    _expectSection(sectionTwo, equals(['two']));
+    var sectionThree = sectionTwo.children[0] as Section;
+    _expectSection(sectionThree, equals(['three']));
+    _expectText(sectionThree.children[0], equals('Text'));
+  });
+
+  test('parses inverse section with multi-name key', () {
+    var parser = MustachioParser('Text {{^one.two}}Text{{/one.two}}');
+    var ast = parser.parse();
+    expect(ast, hasLength(2));
+    _expectText(ast[0], equals('Text '));
+    var sectionOne = ast[1] as Section;
+    _expectSection(sectionOne, equals(['one']));
+    expect(sectionOne.children, hasLength(1));
+    var sectionTwo = sectionOne.children[0] as Section;
+    _expectSection(sectionTwo, equals(['two']), invert: true);
+    _expectText(sectionTwo.children[0], equals('Text'));
+  });
+
   test('parses section with empty key as text', () {
     var parser = MustachioParser('Text {{#}}{{/key}}');
     var ast = parser.parse();

test/mustachio/renderer_test.dart

@@ -175,6 +175,15 @@ void main() {
     expect(renderFoo(foo, fooTemplate), equals('Text Num 1, Num 2, Num 3, '));
   });
 
+  test('Renderer renders a repeated section node with a multi-name key',
+      () async {
+    var barTemplateFile = getFile('/project/bar.mustache')
+      ..writeAsStringSync('Text {{#foo.l1}}Num {{.}}, {{/foo.l1}}');
+    var barTemplate = await Template.parse(barTemplateFile);
+    var bar = Bar()..foo = (Foo()..l1 = [1, 2, 3]);
+    expect(renderBar(bar, barTemplate), equals('Text Num 1, Num 2, Num 3, '));
+  });
+
   test('Renderer renders an empty repeated section node as blank', () async {
     var fooTemplateFile = getFile('/project/foo.mustache')
       ..writeAsStringSync('Text {{#l1}}Num {{.}}, {{/l1}}');
@@ -200,11 +209,11 @@ void main() {
   });
 
   test('Renderer renders a value section node', () async {
-    var fooTemplateFile = getFile('/project/foo.mustache')
+    var barTemplateFile = getFile('/project/bar.mustache')
       ..writeAsStringSync('Text {{#foo}}Foo: {{s1}}{{/foo}}');
-    var fooTemplate = await Template.parse(fooTemplateFile);
+    var barTemplate = await Template.parse(barTemplateFile);
     var bar = Bar()..foo = (Foo()..s1 = 'hello');
-    expect(renderBar(bar, fooTemplate), equals('Text Foo: hello'));
+    expect(renderBar(bar, barTemplate), equals('Text Foo: hello'));
   });
 
   test('Renderer renders a null value section node as blank', () async {
@@ -241,41 +250,41 @@ void main() {
 
   test('Renderer resolves variable from outer context inside a value section',
       () async {
-    var fooTemplateFile = getFile('/project/foo.mustache')
+    var barTemplateFile = getFile('/project/foo.mustache')
       ..writeAsStringSync('Text {{#foo}}{{s2}}{{/foo}}');
-    var fooTemplate = await Template.parse(fooTemplateFile);
+    var barTemplate = await Template.parse(barTemplateFile);
     var bar = Bar()
       ..foo = (Foo()..s1 = 'hello')
       ..s2 = 'goodbye';
-    expect(renderBar(bar, fooTemplate), equals('Text goodbye'));
+    expect(renderBar(bar, barTemplate), equals('Text goodbye'));
   });
 
   test('Renderer resolves variable with key with multiple names', () async {
-    var fooTemplateFile = getFile('/project/foo.mustache')
+    var barTemplateFile = getFile('/project/foo.mustache')
       ..writeAsStringSync('Text {{foo.s1}}');
-    var fooTemplate = await Template.parse(fooTemplateFile);
+    var barTemplate = await Template.parse(barTemplateFile);
     var bar = Bar()
       ..foo = (Foo()..s1 = 'hello')
       ..s2 = 'goodbye';
-    expect(renderBar(bar, fooTemplate), equals('Text hello'));
+    expect(renderBar(bar, barTemplate), equals('Text hello'));
   });
 
   test('Renderer resolves outer variable with key with two names', () async {
-    var fooTemplateFile = getFile('/project/foo.mustache')
+    var barTemplateFile = getFile('/project/foo.mustache')
       ..writeAsStringSync('Text {{#foo}}{{foo.s1}}{{/foo}}');
-    var fooTemplate = await Template.parse(fooTemplateFile);
+    var barTemplate = await Template.parse(barTemplateFile);
     var bar = Bar()
       ..foo = (Foo()..s1 = 'hello')
       ..s2 = 'goodbye';
-    expect(renderBar(bar, fooTemplate), equals('Text hello'));
+    expect(renderBar(bar, barTemplate), equals('Text hello'));
   });
 
   test('Renderer resolves outer variable with key with three names', () async {
-    var fooTemplateFile = getFile('/project/foo.mustache')
+    var bazTemplateFile = getFile('/project/foo.mustache')
       ..writeAsStringSync('Text {{#bar}}{{bar.foo.s1}}{{/bar}}');
-    var fooTemplate = await Template.parse(fooTemplateFile);
+    var bazTemplate = await Template.parse(bazTemplateFile);
     var baz = Baz()..bar = (Bar()..foo = (Foo()..s1 = 'hello'));
-    expect(renderBaz(baz, fooTemplate), equals('Text hello'));
+    expect(renderBaz(baz, bazTemplate), equals('Text hello'));
   });
 
   test('Renderer resolves outer variable with key with more than three names',