dart - dart 上是否有相当于 python 的 dir() ？

Question

dir()正如标题所说，飞镖上是否有相当于蟒蛇的东西？

Answer 1

Python dir() 函数用于找出模块定义的名称。

我们可以使用Mirrors并自己编写一个等效的函数（或至少非常相似）：

import 'dart:mirrors';

List<String> dir([String libraryName]) {
  var lib, symbols = [];

  if (?libraryName) {
    lib = currentMirrorSystem().libraries[libraryName];
  } else {
    lib = currentMirrorSystem().isolate.rootLibrary;
  }

  lib.members.forEach((name, mirror) => symbols.add(name));

  return symbols;
}

现在举个例子：

class Hello {}

bar() => print('yay');

main() {
  var foo = 5;

  print(dir()); // [main, bar, Hello, dir]
}

或者指定一个库：

print(dir('dart:mirrors'));

[MirroredError, TypeMirror, ObjectMirror, _LazyLibraryMirror, TypeVariableMirror, MirrorException, ClassMirror, MirrorSystem, _LocalMirrorSystemImpl, _LocalVMObjectMirrorImpl, DeclarationMirror, _LazyTypeMirror, _LocalClosureMirrorImpl, mirrorSystemOf, _LazyFunctionTypeMirror, _filterMap, MirroredCompilationError, _Mirrors, _LocalClassMirrorImpl, _LocalInstanceMirrorImpl, _LocalTypedefMirrorImpl, _LocalFunctionTypeMirrorImpl, reflect, MethodMirror, _LocalVariableMirrorImpl ，LibraryMirror，_LocalIsolateMirrorImpl，FunctionTypeMirror，_LocalLibraryMirrorImpl，镜像，_LocalObjectMirrorImpl，_LocalMirrorImpl，_makeSignatureString，_LocalTypeVariableMirrorImpl，评论，MirroredUncaughtExceptionError，_LocalParameterMirrorImpl，_LazyTypeVariableMirror，TypedefMirror，VariableMirror，IsolateMirror，currentMirrorSystem，_dartEscape，_LocalMethodMirrorImpl、ClosureMirror、VMReference、ParameterMirror、InstanceMirror、_isSimpleValue、SourceLocation]

这从字面上说明了特定库（模块）中定义的内容。现在，Python 的函数可能存在一些差异，它似乎也对名称进行了排序，但这应该让您有一个良好的开端。