1. recursing quirk
-- euphoria version 1.5
-- there's a little quirk with recursing in euphoria, examine the
-- logic in i_am_a_bug() and i_am_not_a_bug(), it appears the same
-- yet executes differently
-- easy to work-around, but interesting to know
procedure debug(object parameter1, object parameter2)
puts(1, "Parameter 1 is ")
if atom(parameter1) then
puts(1, "an atom.")
else
puts(1, "a sequence.")
end if
puts(1, " Parameter 2 is ")
if atom(parameter2) then
puts(1, "an atom.")
else
puts(1, "a sequence.")
end if
puts(1, "\n")
end procedure
procedure i_am_a_bug(object tom, object jerry)
debug(tom, jerry)
if atom(tom) and sequence(jerry) then
i_am_a_bug(jerry, tom) --lets swap and recurse
end if
end procedure
procedure i_am_not_a_bug(object tom, object jerry)
object tom2, jerry2
debug(tom, jerry)
if atom(tom) and sequence(jerry) then
tom2 = tom
jerry2 = jerry
i_am_not_a_bug(jerry2, tom2) --lets use private variables instead
end if
end procedure
i_am_not_a_bug(1, {1})
puts(1, "looks ok to me, parameters have swapped\n")
i_am_a_bug(1, {1})
puts(1, "my my, I now have two copies of parameter2\n")
Matthew McNamara _
mat at iconz.co.nz o( )
The Internet Company of New Zealand / /\
2. Re: recursing quirk
Matthew McNamara wrote:
>there's a little quirk with recursing in euphoria, examine the
>logic in i_am_a_bug() and i_am_not_a_bug(), it appears the same
>yet executes differently
recursion was nevah my strong point
(show me someone who says their
strong point is recursion and i'll
show you someone who has
STACKS=9e1000,256e10000
in their config.sys)
but i ran your program and got the following output:
----begin paste
Parameter 1 is an atom. Parameter 2 is a sequence.
Parameter 1 is a sequence. Parameter 2 is an atom.
looks ok to me, parameters have swapped
Parameter 1 is an atom. Parameter 2 is a sequence.
Parameter 1 is a sequence. Parameter 2 is an atom.
my my, I now have two copies of parameter2
----end paste
now this was run with euph 2.0 and i dont see a problem?!?!
it's very much granted that i may not know what i'm looking
at here... also it may have been fixed in 2.0???
--eagerly awaiting enlightenment
--Hawke'
3. Re: recursing quirk
On Tue, 25 Aug 1998, Hawke wrote:
> Matthew McNamara wrote:
> >there's a little quirk with recursing in euphoria, examine the
> >logic in i_am_a_bug() and i_am_not_a_bug(), it appears the same
> >yet executes differently
> but i ran your program and got the following output:
> ----begin paste
> Parameter 1 is an atom. Parameter 2 is a sequence.
> Parameter 1 is a sequence. Parameter 2 is an atom.
> looks ok to me, parameters have swapped
> Parameter 1 is an atom. Parameter 2 is a sequence.
> Parameter 1 is a sequence. Parameter 2 is an atom.
> my my, I now have two copies of parameter2
> ----end paste
> now this was run with euph 2.0 and i dont see a problem?!?!
> it's very much granted that i may not know what i'm looking
> at here... also it may have been fixed in 2.0???
Looks like the problem does not occur in version 2.0, in version
1.5 the second to last line reads...
Parameter 1 is a sequence. Parameter 2 is a sequence.
Matthew McNamara _
mat at iconz.co.nz o( )
The Internet Company of New Zealand / /\
4. Re: recursing quirk
Matthew McNamara wrote:
> Looks like the problem does not occur in version 2.0, in version
> 1.5 the second to last line reads...
> Parameter 1 is a sequence. Parameter 2 is a sequence.
AH! now that output would be rapidly approaching the
"errrrr that's not quite right" category...
i must admit i was confused after reading your code
and seeing the output given to me after running it...
heh... couldnt see the problem, but now i do :)
it wasnt creating another set of local variables!
my brain can rest easy now :)
tnx for pointing this out matthew...
--Hawke'
5. Re: recursing quirk
The quirk reported today by Matthew McNamara
was first reported by Jacques Deschenes a year ago.
1.5a and earlier contain the bug. 2.0 is ok.
See doc\relnotes.doc
Regards,
Rob Craig
Rapid Deployment Software
http://members.aol.com/FilesEu/
