Maximally minimal stack trace standardization

Andreas Rossberg rossberg at
Tue Sep 30 07:37:56 PDT 2014

On 30 September 2014 16:31, Sam Tobin-Hochstadt <samth at> wrote:
> On Tue, Sep 30, 2014 at 6:56 AM, Andreas Rossberg <rossberg at> wrote:
>> On 29 September 2014 19:25, Brendan Eich <brendan at> wrote:
>>> Mark S. Miller wrote:
>>>> That's why, IIRC (haven't checked lately), TCO is only specified for calls
>>>> from non-sloppy functions.
>>> PTC (Proper Tail Calls), not TCO. It's confusing to equate the two, from
>>> what I know (corrections welcome0.
>> Hm, people most often refer to "mandatory tail call
>> optimisation/elimination" when talking about a spec level requirement.
>> I have never seen "PTC" used in a formal context, let alone the
>> acronym.
> Clinger's paper, which formalizes the concept, calls it "proper tail
> recursion" in the title, as does the R5RS Scheme standard. Since
> recursion isn't fundamental, though, proper tail calls seems more
> accurate. This terminology is used lots of places these days, such as
> the Lua docs and this (archive of a) post by Guy Steele:

Interesting, good to know. Thanks for the clarification.

(Still wondering what improper tail calls would be.)


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