OpenEuphoria

2. Re: 3.0.2 BUG! ( maybee)

• Posted by Chris Burch <chriscrylex at aol.com> Mar 20, 2007
• 518 views

Hayden McKay wrote:
> 
> I don't know if this one has been posted before...
> }}}
<eucode>
> sequence a,b,c,d
> 
> a = {} b = {} c = {} d = {}
> 
> a &= {}   b = append(b, {})  -- a = {}  b = {{}}
> c &= 1    d = append(d, 1 )  -- c = {1} d = {1}
> </eucode>
{{{

> 
> Whats wrong with 'a' ?

Nothing at all, this looks like normal behaviour.

For &= read 'tack onto the end', and for append read append onto the end

You define a as an empty sequence, which is fine.

So a &= {} reads as 'tack an empty sequence onto an empty sequence'

whereas b is defined as an empty sequence, but you then append another empty
sequence to it - call it a place holder if you like, so that b is no longer
empty, but contains another empty sequence.

Make sense?

Try this

sequence a, b, c, d
a = {} b = {} c = {} d = {}

a &= {}
printf(1, "length(a) = %d\n", {length(a)} )

b = append(b, {})
printf(1, "length(b) = %d\n", {length(b)} )

c &= 1  --this is not empty
printf(1, "length(c) = %d\n", {length(c)} )

d = append(d, 1)
printf(1, "length(d) = %d\n", {length(d)} )

puts(1, 1/0)

> 
> ps. I have a long algorythm with lots of &=, append, [$] stuff that
>     aint workin'. I'll have to trace it to find out more.



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4. Re: 3.0.2 BUG! ( maybee)

• Posted by Derek Parnell <ddparnell at bigpond.com> Mar 21, 2007
• 514 views

Hayden McKay wrote:
> 
> I don't know if this one has been posted before...
> }}}
<eucode>
> sequence a,b,c,d
> 
> a = {} b = {} c = {} d = {}
> 
> a &= {}   b = append(b, {})  -- a = {}  b = {{}}
> c &= 1    d = append(d, 1 )  -- c = {1} d = {1}
> </eucode>
{{{

> 
> Whats wrong with 'a' ?

This is how I remember the difference between &= and append() ...

'&=' adds every element in the source to the target sequence. The length of the
target sequence is increased by the length of the parameter.

'append()' adds the source as a single element to the target sequence. The
length of the target sequence is increased by 1.

Thus 

  a &= {}  

gives every element of {} (i.e. none) is added to a. length(a) is increased by
zero.

  b = append(b, {})

gives the source (an empty sequence) is added to b. length(b) is increased by 1.

To get the same effect as append() when using '&=', wrap the source in '{}'.
Thus

   a &= {{}} 

is the same as 

   a = append(a, {})




-- 
Derek Parnell
Melbourne, Australia
Skype name: derek.j.parnell