Performance concern with let/const

François REMY fremycompany_pub at yahoo.fr
Mon Sep 17 08:44:31 PDT 2012


(Just one opinion)

I'm all in favor of function-level parse errors. This reminds me an article 
of Ian Hickson where he wondered why, to the contrary of CSS, the ECMAScript 
language didn't define a generic syntax defining a well-formed program 
(tokens, parenthesis+brackets balance, ...) and which would replace any 
block he didn't understand by a { throw ParseError() } block.

    function A() {
        ooops {
            return 3;
        }
    }

would be the same as

    function() {
        do { throw new ParseError("..."); }
    }

I don't say we need to go that far (in fact, ASI probably makes it 
impossible), but any progress made to more modularity and lazy compilation 
is good to take. 



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