ES6 doesn't need opt-in

Herby Vojčík herby at
Fri Jan 6 05:57:30 PST 2012

-----Pôvodná správa----- 
From: Axel Rauschmayer
Sent: Friday, January 06, 2012 12:11 PM
To: Allen Wirfs-Brock
Cc: Mark S. Miller ; Brendan Eich ; es-discuss Steen
Subject: Re: ES6 doesn't need opt-in


As a human, I would want an ES6 trigger to appear as early as possible. I 
wouldn’t want to read through a file, encounter an ES6 trigger at the end 
and then have to revise the understanding of the code that I had so far. I 
like the whole-file-or-nothing approach for switching semantics that you 

Dr. Axel Rauschmayer
axel at


But you can! Allen has explicitly said "put 'let ES6;' at the beginning if 
you want to force ES6". As a human, you can argue that it is humanly to 
actually do it. And when the code is such that it is really ES5&ES6 the 
whole time and only at the end the ES6 feature is used, then what? It is so.

I think the Mark Miller's "has the huge benefit that the ES6 spec can avoid 
describing the semantics of non-strict code. Cool." is undepinning what the 
real value behind the Allen's state machine is.


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