module.md

Module Constructor

This is a proposal for the inclusion of an additional primordial variable to all ECMAScript contexts.

• There MUST be a primordial function Module(text, fileName, lineNo)
  • text MUST be parsed the body of a strict-mode Function
  • Module MAY throw a SyntaxError
  • fileName is an optional name for the text, for debuggers
  • lineNo defaults to 1, is coerced to Number internally, and represents the line number corresponding to the beginning of the text within the file indicated by fileName
  • Module MAY be called as a constructor or as a function. Its behavior must be identical in either case.
  • Module returns a Function (for illustration: module(scope))
    • scope is internally coerced to an Object
    • when module is called
      • the function described in text is run in a lexical scope that contains
        • the primordials (Non normatively, these include Array and Object but not legacy, embedding-specific values like window; a citation to a comprehensive list in the specification is needed here)
        • preceding the primordials, a variable corresponding to each owned property of scope
        • such that any free variable in text that is neither mentioned in the scope object or is a primordial throws a ReferenceError at the point it is used.
      • the module returns the value returned by the function
    • the Module instance MUST own a requirements property
      • requirements are an Array
      • requirements must contain the string corresponding to each occurrence of the free variable require that exists in text in which require is called as a function with the String as its argument
    • the Module instance MUST own the fileName property corresponding to the fileName given to the Module constructor.
    • the Module instance MUST own the lineNo property corresponding to the lineNo given to the Module constructor.

Confinement actually. Simple. Rather than saying that all the own properties of the object become defining variables in the scope object, go the other way: say that all free variables in text are looked in the scope object. If they are not present in the scope object, a ReferenceError is thrown.

@erights, Is the intention that primordials be included on the scope object? This implies that anyone using a module would need to explicitly provide such an object. From the usability perspective, I think I prefer that properties owned by the global scope be implicitly communicated, and anything else fall through at run time with a ReferenceError.

The globals defined by ES5 -- such as Array, Object, etc -- could (and probably should) be provided by default, since (once frozen) they convey no authority. Other globals, such as window or document in a browser environment, should not. If they are not explicitly provided on the scope object, then they are denied.

I need a reference to the comprehensive list of ES primordials. Hopefully the revision above addresses the issue of containment.