> -----Original Message----- > From: Garrett Smith [mailto:[EMAIL PROTECTED] > Sent: 18. mars 2008 11:57 > To: Lars Hansen > Cc: es4-discuss Discuss > Subject: Re: ES4 draft: Error classes > > On Mon, Mar 17, 2008 at 12:11 PM, Lars Hansen > <[EMAIL PROTECTED]> wrote: > > (Didn't know who to follow up to so lamely following up to myself.) > > > > Straw proposal for debugging information and backtraces in error > > objects. > > > > > > Issues to watch out for: > > > > * Security / privacy problems if debugging information can > > leak to arbitrary code (realistic attack scenario). > > > > * Code that gets to look into the caller's lexical environment > > is hard to control, makes possibly unwarranted assumptions > > about the implementation, may preclude tail calls. So > > "magic" functionality comes at a cost. > > > > > > Proposal > > > > * New property Error.prototype.context, value null > > > > * New property Error.prototype.backTrace, value null > > > > * When the run-time system throws a standard error object under > > well-defined circumstances (eg, when it throws a TypeError > > because a value of an incompatible type is stored in a > > type-annotated property) then it may, at its discretion, > > create properties "context" and "backTrace" on the new error > > object. The values in these properties will reveal > > information about the static and dynamic location of the error. > > > > How does the stack trace get set? Given a user-defined Error > type - IllegalDateFormatError - what do callers of the > DateFormat have to do to make functions "capture" the stack trace?
Read further. > > The property "backTrace", if not null, must be an array of > > objects of the same type as stored in "context", representing > > a stack trace taken at the point of the creation of the error > > object. The object at property 0 in "backTrace" represents > > the innermost stack frame and is the same object that is stored > > in the "context" property. > > > > Should the stack trace be - backTrace - or - stackTrace - ? > > > > * New subclass of Error called AssertionError > > > > * New expression forms assert(E), assert(E1,E2) > > > > > What does this have to do with getting a stack trace? See your question above. --lars _______________________________________________ Es4-discuss mailing list Es4-discuss@mozilla.org https://mail.mozilla.org/listinfo/es4-discuss
