OpenEuphoria

Re: Maybe not so stupid a question?

• Posted by CChris <christian.cuvier at agriculture.gouv.fr> May 21, 2007
• 500 views

don cole wrote:
> 
> Chris Burch wrote:
> > 
> > don cole wrote:
> > > 
> > > 
> > > }}}
<eucode>
> > > include mylog..e
> > > ------------------------------------------------part of
> > > mylog.e----------------------------------
> > > global test(object aaa)
> > >    if sequence(aaa) then
> > >        printf(1,"length(%s)=%d,{aaa,length(aaa)})--right here
> > 
> > printf(1,"length(%s)=%d", {aaa,length(aaa)} )
> > 
> > your asking it to print out a variable name - theres probably a deep hack to
> > do this,
> > but I don't know what it is. A simpler generic solution would be
> > 
> > }}}
<eucode>
> > include mylog..e
> > ------------------------------------------------part of
> > mylog.e----------------------------------
> > global test(object aaa, sequence var_name)
> >    if sequence(aaa) then
> >        printf(1,"length(%s),=%d for %s,{var_name,length(aaa), aaa})--right
> >        here
> >    end if
> > end procedure
> > --------------------------------------main program--------------------------
> > dog="mutt"
> > test(dog, "dog")
> > </eucode>
{{{

> > 
> > >    end if
> > > end procedure
> > > --------------------------------------main
> > > program--------------------------
> > > dog="mutt"
> > > test(dog)
> > > </eucode>
{{{

> > > Hello everyone,  
> > > 
> > > Maybe someone can help.
> > > 
> > > Where it says "right here" the first %s refers to aaa which will print out
> > > "mutt"
> > > the variable held in dog.
> > > 
> > > But I don't want to print that I want to print the word "dog" the name of
> > > my
> > > variable.
> > > 
> > > Can this be done"?
> > > 
> > > Don Cole
> > 
> > 
> > <a
> > href="http://euallegro.wikispaces.com">http://euallegro.wikispaces.com</a>
> > <a
> > href="http://members.aol.com/chriscrylex/euphoria.htm">http://members.aol.com/chriscrylex/euphoria.htm</a>
> > <a href="http://uboard.proboards32.com/">http://uboard.proboards32.com/</a>
> > <a
> > href="http://members.aol.com/chriscrylex/EUSQLite/eusql.html">http://members.aol.com/chriscrylex/EUSQLite/eusql.html</a>
> 
> Thanks Chris,
> 
>   I don't know why I'm so stupid not to think of that.
> 
> Don Cole

Euphoria is a pass by value language and has no pointer to allevuate the
problem.

Hence, when you pass <dog> as an argument, only the value is passed, possibly
as a pointer. But the target routine has no way to know where the value comes
from. And variable names don't make it to the backend part of the interpreter
anyway.

Since Matt's OOEu implements pass by reference, you should be able to code
something like:

procedure test(byref object x)
print(1,var_name(x))
end procedure

test(dog) would then print "dog". If you pass an expression, I'd expect ""
to be printed, or "_temp#01A" perhaps. But that is OOEu, not plain Euphoria.

CChris