excluding features from sloppy mode

Brendan Eich brendan at mozilla.com
Wed Jan 16 11:39:19 PST 2013

Oliver Hunt wrote:
> let isn't really relevant in sloppy mode, unless we decide to take let 
> over destructuring (which would make me really sad)

You missed the last TC39 meeting, where we agreed (with some misgivings) 
to have both, but to break backward compat if any extant code indexes 
into let:

   var let = str[i]; // let for letter
   let[x] = y; // hmm, indexing into a letter?

where x could be 0 or 'contains' (and y a replacement function, a 
forward polyfill or some such).

The last line above would be destructuring assignment, in sloppy mode 
ES6, per our last f2f meeting. Incompatible but we doubted any real code 
looked like that.


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