Variable also work

.idea/graphql_parser.iml

@@ -0,0 +1,18 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<module type="WEB_MODULE" version="4">
+  <component name="NewModuleRootManager">
+    <content url="file://$MODULE_DIR$">
+      <excludeFolder url="file://$MODULE_DIR$/.pub" />
+      <excludeFolder url="file://$MODULE_DIR$/.tmp" />
+      <excludeFolder url="file://$MODULE_DIR$/build" />
+      <excludeFolder url="file://$MODULE_DIR$/example/packages" />
+      <excludeFolder url="file://$MODULE_DIR$/packages" />
+      <excludeFolder url="file://$MODULE_DIR$/temp" />
+      <excludeFolder url="file://$MODULE_DIR$/tmp" />
+    </content>
+    <orderEntry type="inheritedJdk" />
+    <orderEntry type="sourceFolder" forTests="false" />
+    <orderEntry type="library" name="Dart SDK" level="project" />
+    <orderEntry type="library" name="Dart Packages" level="project" />
+  </component>
+</module>

.idea/modules.xml

@@ -0,0 +1,8 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project version="4">
+  <component name="ProjectModuleManager">
+    <modules>
+      <module fileurl="file://$PROJECT_DIR$/.idea/graphql_parser.iml" filepath="$PROJECT_DIR$/.idea/graphql_parser.iml" />
+    </modules>
+  </component>
+</project>

.idea/runConfigurations/All_Tests.xml

@@ -0,0 +1,6 @@
+<component name="ProjectRunConfigurationManager">
+  <configuration default="false" name="All Tests" type="DartCommandLineRunConfigurationType" factoryName="Dart Command Line Application" singleton="true">
+    <option name="filePath" value="$PROJECT_DIR$/test/all.dart" />
+    <method />
+  </configuration>
+</component>

.idea/runConfigurations/tests_in_graphql_parser.xml

@@ -0,0 +1,8 @@
+<component name="ProjectRunConfigurationManager">
+  <configuration default="false" name="tests in graphql_parser" type="DartTestRunConfigurationType" factoryName="Dart Test" singleton="true" nameIsGenerated="true">
+    <option name="filePath" value="$PROJECT_DIR$" />
+    <option name="scope" value="FOLDER" />
+    <option name="testRunnerOptions" value="-j 4" />
+    <method />
+  </configuration>
+</component>

.idea/vcs.xml

@@ -0,0 +1,6 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project version="4">
+  <component name="VcsDirectoryMappings">
+    <mapping directory="$PROJECT_DIR$" vcs="Git" />
+  </component>
+</project>

example/basic.dart

@@ -7,7 +7,8 @@ final String INPUT = '''
     tagline
   }
 }
-  '''.trim();
+  '''
+    .trim();
 
 main() {
   var tokens = scan(INPUT);

lib/graphql_parser.dart

@@ -1,2 +1,2 @@
 export 'src/language/ast/ast.dart';
-export 'src/language/language.dart';
+export 'src/language/language.dart';

lib/src/language/ast/definition.dart

@@ -1,5 +1,3 @@
 import 'node.dart';
 
-abstract class DefinitionContext extends Node {
+abstract class DefinitionContext extends Node {}
-
-}

lib/src/language/ast/type_condition.dart

@@ -6,10 +6,10 @@ class TypeConditionContext extends Node {
   final TypeNameContext typeName;
 
   TypeConditionContext(this.typeName);
-  
+
   @override
   SourceSpan get span => typeName.span;
 
   @override
   String toSource() => typeName.toSource();
-}
+}

lib/src/language/ast/variable.dart

@@ -7,6 +7,8 @@ class VariableContext extends Node {
 
   VariableContext(this.DOLLAR, this.NAME);
 
+  String get name => NAME.text;
+
   @override
   SourceSpan get span =>
       new SourceSpan(DOLLAR?.span?.start, NAME?.span?.end, toSource());

lib/src/language/language.dart

@@ -4,4 +4,4 @@ export 'lexer.dart';
 export 'parser.dart';
 export 'syntax_error.dart';
 export 'token.dart';
-export 'token_type.dart';
+export 'token_type.dart';

lib/src/language/lexer.dart

@@ -45,7 +45,8 @@ List<Token> scan(String text) {
 
     for (var pattern in _patterns.keys) {
       if (scanner.matches(pattern)) {
-        potential.add(new Token(_patterns[pattern], scanner.lastMatch[0], scanner.lastSpan));
+        potential.add(new Token(
+            _patterns[pattern], scanner.lastMatch[0], scanner.lastSpan));
       }
     }
 
@@ -57,7 +58,6 @@ List<Token> scan(String text) {
       // Choose longest token
       potential.sort((a, b) => b.text.length.compareTo(a.text.length));
       var chosen = potential.first;
-      var start = scanner.state;
       out.add(chosen);
       scanner.scan(chosen.text);
     }

lib/src/language/token_type.dart

@@ -23,4 +23,4 @@ enum TokenType {
   STRING,
 
   NAME
-}
+}

test/all.dart

@@ -0,0 +1,6 @@
+import 'package:test/test.dart';
+import 'value_test.dart' as value;
+
+main() {
+  group('value', value.main);
+}

test/common.dart

@@ -1,23 +1,7 @@
 import 'package:graphql_parser/graphql_parser.dart';
 import 'package:matcher/matcher.dart';
+import 'package:test/test.dart';
 
 Parser parse(String text) => new Parser(scan(text));
 
-Matcher equalsParsed(value) => new _EqualsParsed(value);
+final Matcher throwsSyntaxError = throwsA(const isInstanceOf<SyntaxError>());
-
-class _EqualsParsed extends Matcher {
-  final value;
-
-  _EqualsParsed(this.value);
-
-  @override
-  Description describe(Description description)
-  => description.add('equals $value when parsed as a GraphQL value');
-
-  @override
-  bool matches(String item, Map matchState) {
-   var p = parse(item);
-   var v = p.parseValue();
-   return equals(value).matches(v.value, matchState);
-  }
-}

test/value_test.dart

@@ -1,4 +1,5 @@
 import 'dart:math' as math;
+import 'package:graphql_parser/graphql_parser.dart';
 import 'package:test/test.dart';
 import 'common.dart';
 
@@ -20,8 +21,8 @@ main() {
 
   test('array', () {
     expect('[]', equalsParsed([]));
-    expect('[1,2]', equalsParsed([1,2]));
+    expect('[1,2]', equalsParsed([1, 2]));
-    expect('[1,2,       3]', equalsParsed([1,2,3]));
+    expect('[1,2,       3]', equalsParsed([1, 2, 3]));
     expect('["a"]', equalsParsed(['a']));
   });
 
@@ -38,4 +39,28 @@ main() {
     expect('"\\u0123"', equalsParsed('\u0123'));
     expect('"\\u0123\\u4567"', equalsParsed('\u0123\u4567'));
   });
+
+  test('exceptions', () {
+    expect(() => parseValue('[1'), throwsSyntaxError);
+  });
+}
+
+ValueContext parseValue(String text) => parse(text).parseValue();
+Matcher equalsParsed(value) => new _EqualsParsed(value);
+
+class _EqualsParsed extends Matcher {
+  final value;
+
+  _EqualsParsed(this.value);
+
+  @override
+  Description describe(Description description) =>
+      description.add('equals $value when parsed as a GraphQL value');
+
+  @override
+  bool matches(String item, Map matchState) {
+    var p = parse(item);
+    var v = p.parseValue();
+    return equals(value).matches(v.value, matchState);
+  }
 }

test/variable_test.dart

@@ -0,0 +1,37 @@
+import 'package:test/test.dart';
+import 'common.dart';
+
+main() {
+  test('variables', () {
+    expect(r'$a', isVariable('a'));
+    expect(r'$abc', isVariable('abc'));
+    expect(r'$abc123', isVariable('abc123'));
+    expect(r'$_', isVariable('_'));
+    expect(r'$___', isVariable('___'));
+    expect(r'$_123', isVariable('_123'));
+  });
+
+  test('exceptions', () {
+    expect(() => parse(r'$').parseVariable(), throwsSyntaxError);
+  });
+}
+
+Matcher isVariable(String name) => new _IsVariable(name);
+
+class _IsVariable extends Matcher {
+  final String name;
+
+  _IsVariable(this.name);
+
+  @override
+  Description describe(Description description) {
+    return description.add('parses as a variable named "$name"');
+  }
+
+  @override
+  bool matches(String item, Map matchState) {
+    var p = parse(item);
+    var v = p.parseVariable();
+    return equals(name).matches(v?.name, matchState);
+  }
+}