On Fri, 2003-05-02 at 14:15, Nick Forde wrote:
> So my best solution is still:
>
> DEFINE foo ==
> [+] cons [infra dup rest cons] cons
> [dupd swons swons].
>
> Are there no other takers? There must be a better Joy implementation
> than this. Also the first call to this function only initialises the
> accumulator, whereas it should actually execute the first accumulate
> operation.

The problem statement is still opaque to me so I've probably
misunderstood. Below is a solution (?) in Monkey (my Joy-alike) but the
Joy version (untested) would be:

DEFINE foo ==
[ + foo ] cons .

Or is explicit recursion not allowed?

----snip--snip----

<< -----------------------
Accumulator generators.
----------------------- >>

module main provides main .
uses io .

<< Entry point of program. >>
main ==
{{
3 accgen << First invocation >>
dup . nl << Show result (accum=3). >>

1 swap i << 2nd invocation. >>
dup . nl << Show result (accum=4). >>

dup << Keep a copy of this accumulator function. >>

5 swap i << Accumlate again. >>
dup . 10 emit << Show result (accum=9). >>

drop << Drop the last accumulator, revery to
previously saved one. >>

2 swap i << Acuum. again. >>
dup . 10 emit << Show result (accum=6). >>
}}

<< The generator. >>
accgen ==
{{
[ + accgen ] cons programise
}}

----snip--snip----

Output is:

[my@upstairs MONKEY]$ ./monkey accgen.mmod
Creating stub module definition for "main".
Creating stub module definition for "io".
Will scan "io".
Creating stub module definition for "control".
Will scan "control".
{ 3 + accgen }
{ 4 + accgen }
{ 9 + accgen }
{ 6 + accgen }