[Maxima-bugs] [ maxima-Bugs-1222927 ] scope for a variable in buildq?

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Bugs item #1222927, was opened at 2005-06-17 15:54
Message generated for change (Comment added) made by robert_dodier
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Category: Lisp Core
Group: Fix for 5.9.2
>Status: Closed
>Resolution: Wont Fix
Priority: 5
Submitted By: van_Nek (van_nek)
Assigned to: Nobody/Anonymous (nobody)
Summary: scope for a variable in buildq?

Initial Comment:
(%i1)
printlist(list)::=buildq([temp:ev(list)],print(splice(temp)))$
(%i2) list:[1,2,3]$
(%i3) printlist(list);
SPLICE(TEMP) returned LIST
But SPLICE must return a list
#0: printlist(list=LIST)
 -- an error.  Quitting.  To debug this try
DEBUGMODE(TRUE);
(%i4) ref:list$
(%i5) printlist(ref);
1 2 3 
(%o5) 				       3

this is confusing!

(%i12) f(x):=x**2$
(%i13) x:3$
(%i14) f(x);
(%o14) 				       9

that works!

Am I not allowed to use any name for a variable in buildq?

van_Nek
va...@gm...

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>Comment By: Robert Dodier (robert_dodier)
Date: 2005-08-31 08:45

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As stated below, the phenomenon observed here is a
consequence of the rules of binding and evaluation. So I am
closing this report as a non-bug. 

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Comment By: van_Nek (van_nek)
Date: 2005-06-21 10:10

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Dear Robert Dodier,
thanks for your answer.
I am not really happy with the work of SPLICE in BUILDQ,
but you showed, that with the use of APPLY there is a much
easier way.
Volker van Nek

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Comment By: Robert Dodier (robert_dodier)
Date: 2005-06-18 20:24

Message:
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The problem is that before expanding printlist, the formal
argument list is bound to the actual argument, also named
list. Given that, ev (list) => list (not the actual [1, 2,
3]) and then splice complains. Same complaint if the formal
and actual arguments have the same name (something other
than "list"), e.g., FOO.

This is strange, although I'm not sure if it can be
considered a bug, as it is a straightforward consequence of
the general rules for binding and evaluation.

In any event, maybe apply (print, list) has the effect you
want? How about:

  printlist (list) := apply (print, list);

  list: [1,2,3];

  printlist (list);
1 2 3 
                               3



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