proper tail calls still out of es4?

Brendan Eich brendan at
Sun Jul 6 15:52:36 PDT 2008

On Jul 6, 2008, at 3:14 PM, Peter Michaux wrote:

> Hi,
> I'm just curious if there has been any discussion about adding proper
> tail calls back into es4 or if it is definitely out for good.

Background links:

Since we aren't done and we are implementing before standardizing,  
it's impossible to say "for good", but our work is easier as spec- 
writiers, and implementors of prototype specs have it easier too, if  
there are fewer requirements operating on the syntactic analysis and  
runtime semantics.

My belief is that if proper tail calls are to make a come-back, it  
will be through implementors leading the way. As discussed in the  
linked documents cited above, support by popular implementations on  
the web would tend to force a de-facto standard. This might not be  
evident by the time ES4 is standardized, but it could be folded into  
a successor standard.


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