Firefox/Chrome: {} + {} etc.

Allen Wirfs-Brock allen at wirfs-brock.com
Fri Jan 27 10:03:49 PST 2012


On Jan 27, 2012, at 8:38 AM, Luke Hoban wrote:

> JS REPLs tend to parse input as Program productions.  Parsing "{} + {}" as a block followed by a unary expression is correct according to ES5 grammar for Program.  IE behaves the same.  
> 

It's not just in Program, it's any statement context.  However, it is hard to actually observe outside of a REPL.  Try this variant

function f() {
   {;} + {}
}

to more clearly see what is being parsed.

{ } + {}

clearly belongs in anybodies wtfjs list

Allen



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