Sky Script Language

The Sky script language is Dart.

The way that Sky integrates the module system with its script language is described in modules.md.

All the APIs defined in this documentation, unless explicitly called out as being in a framework, are in the dart:sky built-in module.

When a method in dart:sky defined as external receives an argument, it must type-check it, and, if the argument's value is the wrong type, then it must throw an ArgumentError as follows:

throw new ArgumentError(value, name: name);

...where “name” is the name of the argument. Type checking here includes rejecting nulls unless otherwise indicated or unless null is argument's default value.

The following definitions are exposed in dart:sky:

import 'dart:mirrors';

abstract class AutomaticMetadata {
  const AutomaticMetadata();
  void init(DeclarationMirror target, Module module, ScriptElement script);

  static void runLibrary(LibraryMirror library, Module module, ScriptElement script) {
    library.declarations.values.toList() /* ..sort((DeclarationMirror a, DeclarationMirror b) {
      bool aHasLocation;
      try {
        aHasLocation = a.location != null;
      } catch(e) {
        aHasLocation = false;
      }
      bool bHasLocation;
      try {
        bHasLocation = b.location != null;
      } catch(e) {
        bHasLocation = false;
      }
      if (!aHasLocation)
        return bHasLocation ? 1 : 0;
      if (!bHasLocation)
        return -1;
      if (a.location.sourceUri != b.location.sourceUri)
        return a.location.sourceUri.toString().compareTo(b.location.sourceUri.toString());
      if (a.location.line != b.location.line)
        return a.location.line - b.location.line;
      return a.location.column - b.location.column;
    }) */
    ..forEach((DeclarationMirror d) {
      d.metadata.forEach((InstanceMirror i) {
        if (i.reflectee is AutomaticMetadata)
          i.reflectee.run(d, module, script);
      });
    });
  }
}

class AutomaticFunction extends AutomaticMetadata {
  const AutomaticFunction();
  void init(DeclarationMirror target, Module module, ScriptElement script) {
    assert(target is MethodMirror);
    MethodMirror f = target as MethodMirror;
    assert(!f.isAbstract);
    assert(f.isRegularMethod);
    assert(f.isTopLevel);
    assert(f.isStatic);
    assert(f.parameters.length == 1);
    assert(f.parameters[0].type == ScriptElement);
    assert(f.returnType == currentMirrorSystem().voidType);
    (f.owner as LibraryMirror).invoke(f.simpleName, [script]);
  }
}
const autorun = const AutomaticFunction();

Extensions

The following as-yet unimplemented features of the Dart language are assumed to exist:

• It is assumed that a subclass can define a constructor by reference to a superclass' constructor, wherein the subclass' constructor has the same arguments as the superclass' constructor and does nothing but invoke that superclass' constructor with the same arguments. The syntax for defining this is, within the class body for a class called ClassName:

     ClassName = SuperclassName;
     ClassName.namedConstructor = SuperclassName.otherNamedConstructor;

• The reflection APIs (dart:mirrors) are assumed to reflect a library's declarations in source order.