Dart: Symbol Cheat Sheet

Symbol obj = new Symbol('name');  
// expects a name of class or function or library to reflect 

# Foo.dart

library foo_lib;   
// libarary name can be a symbol   
class Foo {         
   // class name can be a symbol  
   m1() {        
      // method name can be a symbol 
      print("Inside m1"); 
   } 
   m2() { 
      print("Inside m2"); 
   } 
   m3() { 
      print("Inside m3"); 
   } 
}

# FooSymbol.dart

import 'dart:core'; 
import 'dart:mirrors'; 
import 'Foo.dart';  
main() { 
   Symbol lib = new Symbol("foo_lib");   
   //library name stored as Symbol 
   Symbol clsToSearch = new Symbol("Foo");  
   // class name stored as Symbol  
   if(checkIf_classAvailableInlibrary(lib, clsToSearch))  
   // searches Foo class in foo_lib library 
      print("class found.."); 
}  
bool checkIf_classAvailableInlibrary(Symbol libraryName, Symbol className) { 
   MirrorSystem mirrorSystem = currentMirrorSystem(); 
   LibraryMirror libMirror = mirrorSystem.findLibrary(libraryName); 
   if (libMirror != null) { 
      print("Found Library"); 
      print("checkng...class details.."); 
      print("No of classes found is : ${libMirror.declarations.length}"); 
      libMirror.declarations.forEach((s, d) => print(s));  
      if (libMirror.declarations.containsKey(className)) return true; 
      return false; 
   } 
}

=> output

Found Library 
checkng...class details.. 
No of classes found is : 1 
Symbol("Foo") // class name displayed as symbol  
class found. 

# Convert Symbol to String

import 'dart:mirrors'; 
void main(){ 
   Symbol lib = new Symbol("foo_lib"); 
   String name_of_lib = MirrorSystem.getName(lib); 
   print(lib); 
   print(name_of_lib); 
}

=> output

Symbol("foo_lib")   
foo_lib