Boom expression args (#133)

* Initial support for Expression(s).

* More in changelog.

* Add context everywhere.

* All tests passing.

* More cleanup.

* More expression work.

* Improve calls, add property access.

* Update README.

* Actually update it.

* Be nice to users.

* Add literalString, literalMap.

Author: matanlurey

CHANGELOG.md

@@ -8,25 +8,31 @@
 * Added `show|hide` to `Directive`.
 * Added `Directive.importDeferredAs`.
 * Added a new line character after emitting some types (class, method, etc).
+* Added `refer` as a short-hand for `new Reference(...)`.
+  * `Reference` now implements `Expression`.
 
-* `SpecVisitor<T>`'s methods all have an optional `[T context]` parameter now.
-  * This makes it much easier to avoid allocating extra `StringBuffer`s.
-* Removed `SimpleSpecVisitor` (it was unused).
-* Removed `implements Reference` from `Method` and `Field`; not a lot of value. 
-* `equalsDart` removes insignificant white space before comparing results.
-
-* In process of adding classes/methods for writing bodies of `Code` fluently:
+* Added many classes/methods for writing bodies of `Code` fluently:
   * `Expression`
   * `LiteralExpression`
     * `literal`
     * `literalNull`
     * `literalBool`
     * `literalTrue`
     * `literalFalse`
-    * `literalList`
+    * `literalNum`
+    * `literalString`
+    * `literalList` and `literalConstList`
+    * `literalMap` and `literalConstMap`
   * `const Code(staticString)`
   * `const Code.scope((allocate) => '')`
 
+* Removed `SimpleSpecVisitor` (it was unused).
+* Removed `implements Reference` from `Method` and `Field`; not a lot of value. 
+
+* `SpecVisitor<T>`'s methods all have an optional `[T context]` parameter now.
+  * This makes it much easier to avoid allocating extra `StringBuffer`s.
+* `equalsDart` removes insignificant white space before comparing results.
+
 ## 2.0.0-alpha+1
 
 * Removed `Reference.localScope`. Just use `Reference(symbol)` now.

README.md

@@ -40,11 +40,11 @@ import 'package:dart_style/dart_style.dart';
 void main() {
   final animal = new Class((b) => b
     ..name = 'Animal'
-    ..extend = const Reference('Organism').toType()
+    ..extend = refer('Organism').toType()
     ..methods.add(new Method.returnsVoid((b) => b
       ..name = 'eat'
       ..lambda = true
-      ..body = new Code((b) => b..code = 'print(\'Yum\')'))));
+      ..body = const Code('print(\'Yum\')'))));
   final emitter = const DartEmitter();
   print(new DartFormatter().format('${animal.accept(emitter)}'));
 }
@@ -70,11 +70,11 @@ void main() {
         new Method((b) => b
           ..body = new Code((b) => b.code = '')
           ..name = 'doThing'
-          ..returns = const Reference('Thing', 'package:a/a.dart')),
+          ..returns = refer('Thing', 'package:a/a.dart')),
         new Method((b) => b
           ..body = new Code((b) => b..code = '')
           ..name = 'doOther'
-          ..returns = const Reference('Other', 'package:b/b.dart')),
+          ..returns = refer('Other', 'package:b/b.dart')),
       ]));
   final emitter = new DartEmitter(new Allocator.simplePrefixing());
   print(new DartFormatter().format('${library.accept(emitter)}'));

example/animal.dart

@@ -8,7 +8,7 @@ import 'package:dart_style/dart_style.dart';
 void main() {
   final animal = new Class((b) => b
     ..name = 'Animal'
-    ..extend = const Reference('Organism')
+    ..extend = refer('Organism')
     ..methods.add(new Method.returnsVoid((b) => b
       ..name = 'eat'
       ..lambda = true

example/scope.dart

@@ -10,11 +10,11 @@ void main() {
         new Method((b) => b
           ..body = const Code('')
           ..name = 'doThing'
-          ..returns = const Reference('Thing', 'package:a/a.dart')),
+          ..returns = refer('Thing', 'package:a/a.dart')),
         new Method((b) => b
           ..body = const Code('')
           ..name = 'doOther'
-          ..returns = const Reference('Other', 'package:b/b.dart')),
+          ..returns = refer('Other', 'package:b/b.dart')),
       ]));
   final emitter = new DartEmitter(new Allocator.simplePrefixing());
   print(new DartFormatter().format('${library.accept(emitter)}'));

lib/code_builder.dart

@@ -28,6 +28,9 @@ export 'src/specs/expression.dart'
         literalBool,
         literalList,
         literalConstList,
+        literalMap,
+        literalConstMap,
+        literalString,
         literalTrue,
         literalFalse;
 export 'src/specs/field.dart' show Field, FieldBuilder, FieldModifier;
@@ -40,5 +43,5 @@ export 'src/specs/method.dart'
         MethodType,
         Parameter,
         ParameterBuilder;
-export 'src/specs/reference.dart' show Reference;
+export 'src/specs/reference.dart' show refer, Reference;
 export 'src/specs/type_reference.dart' show TypeReference, TypeReferenceBuilder;

lib/src/emitter.dart

@@ -2,6 +2,8 @@
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
+import 'package:meta/meta.dart';
+
 import 'allocator.dart';
 import 'base.dart';
 import 'specs/annotation.dart';
@@ -17,6 +19,33 @@ import 'specs/reference.dart';
 import 'specs/type_reference.dart';
 import 'visitors.dart';
 
+/// Helper method improving on [StringSink.writeAll].
+///
+/// For every `Spec` in [elements], executing [visit].
+///
+/// If [elements] is at least 2 elements, inserts [separator] delimiting them.
+@visibleForTesting
+void visitAll<T>(
+  Iterable<T> elements,
+  StringSink output,
+  void visit(T element), [
+  String separator = ', ',
+]) {
+  // Basically, this whole method is an improvement on
+  //   output.writeAll(specs.map((s) => s.accept(visitor));
+  //
+  // ... which would allocate more StringBuffer(s) for a one-time use.
+  if (elements.isEmpty) {
+    return;
+  }
+  final iterator = elements.iterator..moveNext();
+  visit(iterator.current);
+  while (iterator.moveNext()) {
+    output.write(separator);
+    visit(iterator.current);
+  }
+}
+
 class DartEmitter extends Object
     with CodeEmitter, ExpressionEmitter
     implements SpecVisitor<StringSink> {

lib/src/specs/code.dart

@@ -8,9 +8,10 @@ import 'package:meta/meta.dart';
 
 import '../allocator.dart';
 import '../base.dart';
-import '../specs/reference.dart';
 import '../visitors.dart';
 
+import 'reference.dart';
+
 /// Returns a scoped symbol to [Reference], with an import prefix if needed.
 ///
 /// This is short-hand for [Allocator.allocate] in most implementations.

lib/src/specs/expression.dart

@@ -7,6 +7,7 @@ library code_builder.src.specs.expression;
 import 'package:meta/meta.dart';
 
 import '../base.dart';
+import '../emitter.dart';
 import '../visitors.dart';
 import 'code.dart';
 import 'reference.dart';
@@ -25,31 +26,77 @@ abstract class Expression implements Spec {
   @override
   R accept<R>(covariant ExpressionVisitor<R> visitor, [R context]);
 
+  /// Returns the expression as a valid [Code] block.
+  Code asCode() => new _AsExpressionCode(this);
+
   /// Returns the result of [this] `&&` [other].
   Expression and(Expression other) {
     return new BinaryExpression._(toExpression(), other, '&&');
   }
 
   /// Call this expression as a method.
-  Expression call() {
-    return new InvokeExpression._(this);
+  Expression call(
+    List<Expression> positionalArguments, [
+    Map<String, Expression> namedArguments = const {},
+  ]) {
+    return new InvokeExpression._(
+      this,
+      positionalArguments,
+      namedArguments,
+    );
+  }
+
+  /// Returns an expression accessing `.<name>` on this expression.
+  Expression property(String name) {
+    return new BinaryExpression._(
+      this,
+      new LiteralExpression._(name),
+      '.',
+      false,
+    );
   }
 
   /// Returns a new instance of this expression.
-  Expression newInstance() {
-    return new InvokeExpression._new(this);
+  Expression newInstance(
+    List<Expression> positionalArguments, [
+    Map<String, Expression> namedArguments = const {},
+  ]) {
+    return new InvokeExpression._new(
+      this,
+      positionalArguments,
+      namedArguments,
+    );
   }
 
   /// Returns a const instance of this expression.
-  Expression constInstance() {
-    return new InvokeExpression._const(this);
+  Expression constInstance(
+    List<Expression> positionalArguments, [
+    Map<String, Expression> namedArguments = const {},
+  ]) {
+    return new InvokeExpression._const(
+      this,
+      positionalArguments,
+      namedArguments,
+    );
   }
 
   /// May be overriden to support other types implementing [Expression].
   @visibleForOverriding
   Expression toExpression() => this;
 }
 
+/// Represents a [code] block that wraps an [Expression].
+class _AsExpressionCode implements Code {
+  final Expression code;
+
+  const _AsExpressionCode(this.code);
+
+  @override
+  R accept<R>(CodeVisitor<R> visitor, [R context]) {
+    return code.accept(visitor as ExpressionVisitor<R>, context);
+  }
+}
+
 /// Knowledge of different types of expressions in Dart.
 ///
 /// **INTERNAL ONLY**.
@@ -59,6 +106,7 @@ abstract class ExpressionVisitor<T> implements SpecVisitor<T> {
   T visitInvokeExpression(InvokeExpression expression, [T context]);
   T visitLiteralExpression(LiteralExpression expression, [T context]);
   T visitLiteralListExpression(LiteralListExpression expression, [T context]);
+  T visitLiteralMapExpression(LiteralMapExpression expression, [T context]);
 }
 
 /// Knowledge of how to write valid Dart code from [ExpressionVisitor].
@@ -68,12 +116,16 @@ abstract class ExpressionEmitter implements ExpressionVisitor<StringSink> {
   @override
   visitBinaryExpression(BinaryExpression expression, [StringSink output]) {
     output ??= new StringBuffer();
-    return output
-      ..write(expression.left.accept(this))
-      ..write(' ')
-      ..write(expression.operator)
-      ..write(' ')
-      ..write(expression.right.accept(this));
+    expression.left.accept(this, output);
+    if (expression.addSpace) {
+      output.write(' ');
+    }
+    output.write(expression.operator);
+    if (expression.addSpace) {
+      output.write(' ');
+    }
+    expression.right.accept(this, output);
+    return output;
   }
 
   @override
@@ -95,7 +147,19 @@ abstract class ExpressionEmitter implements ExpressionVisitor<StringSink> {
         break;
     }
     expression.target.accept(this, output);
-    return output..write('()');
+    output.write('(');
+    visitAll<Spec>(expression.positionalArguments, output, (spec) {
+      spec.accept(this, output);
+    });
+    if (expression.positionalArguments.isNotEmpty &&
+        expression.namedArguments.isNotEmpty) {
+      output.write(', ');
+    }
+    visitAll<String>(expression.namedArguments.keys, output, (name) {
+      output..write(name)..write(': ');
+      expression.namedArguments[name].accept(this, output);
+    });
+    return output..write(')');
   }
 
   @override
@@ -104,6 +168,14 @@ abstract class ExpressionEmitter implements ExpressionVisitor<StringSink> {
     return output..write(expression.literal);
   }
 
+  void _acceptLiteral(Object literalOrSpec, StringSink output) {
+    if (literalOrSpec is Spec) {
+      literalOrSpec.accept(this, output);
+      return;
+    }
+    literal(literalOrSpec).accept(this, output);
+  }
+
   @override
   visitLiteralListExpression(
     LiteralListExpression expression, [
@@ -119,18 +191,39 @@ abstract class ExpressionEmitter implements ExpressionVisitor<StringSink> {
       output.write('>');
     }
     output.write('[');
-    // ignore: prefer_final_locals
-    for (var i = 0, l = expression.values.length; i < l; i++) {
-      final value = expression.values[i];
-      if (value is Spec) {
-        value.accept(this, output);
+    visitAll<Object>(expression.values, output, (value) {
+      _acceptLiteral(value, output);
+    });
+    return output..write(']');
+  }
+
+  @override
+  visitLiteralMapExpression(
+    LiteralMapExpression expression, [
+    StringSink output,
+  ]) {
+    output ??= new StringBuffer();
+    if (expression.isConst) {
+      output.write('const ');
+    }
+    if (expression.keyType != null) {
+      output.write('<');
+      expression.keyType.accept(this, output);
+      output.write(', ');
+      if (expression.valueType == null) {
+        const Reference('dynamic', 'dart:core').accept(this, output);
       } else {
-        literal(value).accept(this, output);
-      }
-      if (i < l - 1) {
-        output.write(', ');
+        expression.valueType.accept(this, output);
       }
+      output.write('>');
     }
-    return output..write(']');
+    output.write('{');
+    visitAll<Object>(expression.values.keys, output, (key) {
+      final value = expression.values[key];
+      _acceptLiteral(key, output);
+      output.write(': ');
+      _acceptLiteral(value, output);
+    });
+    return output..write('}');
   }
 }

lib/src/specs/expression/binary.dart

@@ -9,8 +9,14 @@ class BinaryExpression extends Expression {
   final Expression left;
   final Expression right;
   final String operator;
+  final bool addSpace;
 
-  const BinaryExpression._(this.left, this.right, this.operator);
+  const BinaryExpression._(
+    this.left,
+    this.right,
+    this.operator, [
+    this.addSpace = true,
+  ]);
 
   @override
   R accept<R>(ExpressionVisitor<R> visitor, [R context]) {