OpenEuphoria

Re: Warning error

• Posted by Bob Elia <bobelia200 at netzero.net> Feb 27, 2007
• 495 views

CChris wrote:
> 
> Bob Elia wrote:
> > 
> > Pete Lomax wrote:
> > 
> > <snip>
> > 
> > > Regards,
> > > Pete
> > > PS I vote for {}=xxx(), btw, very Eu-like, as I read it as "nothing
> > > becomes
> > > equal to the result of xxx()" or I suppose if you prefer, "store the
> > > result
> > > of xxx() in nothing/nowhere". Whereas I never really liked the ~xxx()
> > > idea.
> > > Plus it ties up nicely with my plans for multiple assignment, and also I
> > > always
> > > found "{}=" dead easy to type, actually easier/faster than "~" even
> > > thought
> > > it is three keys(I regularly use) not one(I rarely use).
> > 
> > Hi Pete,
> > 
> > Multiple assignment would be terrific but please don't use braces for this.
> > 
> > I much prefer parentheses; e.g.
> > 
> > }}}
<eucode>
> > {a, b, c) = somefunc()
> > 
> > -- Using braces makes it look like sequence formation, which it is not:
> > 
> > {d,e,f} = another_func()
> > </eucode>
{{{

> > 
> > Also, (I may be nit-picking here) when you say "nothing becomes equal to..."
> > as in "{}=xxx()", the empty braces have a very specific meaning, that is,
> > "the empty sequence", not "nothing".  At least, I find it jarring to look
> > at.
> > 
> > Unless, of course, I've misunderstood your intention. ;)
> > 
> > BTW, I take it you are familiar with Daryl Border's implementation of
> > multiple assignment called "seqparse" from 2005.
> > 
> > Thanks,
> > Bob
> 
> Please don't use parentheses or square brackets. Look at the following code:
> }}}
<eucode>
> x=f
> (d,e,c)=something()
> </eucode>
{{{

> The interpreter will be confused because f is not supposed to have any 
> arguments, yet the code reads:
> }}}
<eucode>
> x=f(d,e,c)=something()
> </eucode>
{{{

> Even more irritating, the latter does have a meaning in Eu already, which is
> 
> not the one that was intended.

Yes, of course. That slipped by me completely.

> 
> As you can see, replacing parens by square brackets doesn't help, because, 
> when the comma appears, the interpreter is already subscripting f.
> 
> This leaves us with:
> * {...}, my preference,
> * |...| : pipes are not often easy to tell from square brackets, and, on non
>  english keyboards, | and [ are on adjacent keys, calling for more typos.
> * <...> : will confuse the interpreter. Remember that it is very myopic, and
>  has to know at each character how it is going to read that character. It 
> exceptionally looks ahead one char forth so as to read the slice symbol
> or relational operators, but that's nearly all.
> * perhaps <<...>> would be acceptable.
> * perhaps ;...; would be acceptable.
> 
> So my vote is for curly braces.
> 
> {}=func() doesn't shock me at all. It is an empty sequence of placeholders.
>  So, no assignment is to take place, since there is no target for assignment.
> 

If {} is okay, then I'd rather not introduce new syntax elements.  They might
be needed in the future for something else.  Agreed?

> In my private idEu preprocessor, I use a single _ as placeholder in various
>  contexts. For instance, I write
> }}}
<eucode>
> a[b[c]][d]=append(_,something)
> </eucode>
{{{

> where _ resolves to the left hand side.
> And
> }}}
<eucode>
> {a,_,c}=f
> </eucode>
{{{

> if I wish to ignore the second element in the right hand side.  I had coded
> 
> the beast so that {}, {_} or _ on the left would all cause no assignment 
> to take place.
> 
> 
> Any thoughts?
> 
> CChris

Thanks, Bob