[Tcl-bugs] [ tcl-Bugs-449279 ] [namespace which -var] ignores aliases

[<no...@so...>]

Bugs item #449279, was opened at 2001-08-08 13:35
You can respond by visiting: 
http://sourceforge.net/tracker/?func=detail&atid=110894&aid=449279&group_id=10894

Category: 20. [namespace]
Group: 8.4a3
Status: Open
Resolution: None
Priority: 5
Submitted By: Don Porter (dgp)
>Assigned to: miguel sofer (msofer)
Summary: [namespace which -var] ignores aliases

Initial Comment:

% namespace eval foo variable x 1
% namespace eval bar variable x 2
% proc bar::test {} {
      variable ::foo::x	;# 'x' is now an alias for
			;# ::foo::x
      set x 3		;# sets ::foo::x
      puts "x is [namespace which -variable x]"
  }
% bar::test
x is ::bar::x
% set bar::x
2
% set foo::x
3

This is not what I expect.  I expect
[namespace which -variable x] to tell
me something about what "x" refers to
in the current context.  But [namespace which]
is completely ignoring the local alias "x"
and telling me how it would resolve "x"
looking in the current and global namespaces
only.  That has nothing to do with how operations
on "x" will behave, which is what I really want
to know.

Here the local variable alias was created with
[variable], but the same problem exists when
local variables are created with [upvar] or
just by creating a local variable.

As is, [namespace which] is not the tool I need.
The tool I need appears to be missing.  What
I need is the analog of [namespace origin] for
variables.



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Comment By: Don Porter (dgp)
Date: 2001-08-08 16:36

Message:
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After chat discussions with Miguel, it seems
there's both a bug and a feature request here.

[namespace which -variable] should reflect the
actual resolution rules.  As is, when called
inside a proc, it doesn't examine the local context
at all.  Also, when the variable name does not
contain any namespace qualifiers, it's resolution
will not involve other namespaces at all, yet
[namespace which -var] will still act like it does.

In the example, it would be better to see

	% bar::test
	x is x

Indicating that in the context of the body of
proc [bar::test], "x" is a local variable, and
won't be resolved in other namespaces.

In addition, we need the ability to determine the
ultimate reference of local variables that are
really aliases created by [upvar], [variable],
etc.  That's the Feature Request part, and will
need some thinking.  (What about references to
other proc contexts?, etc.)

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You can respond by visiting: 
http://sourceforge.net/tracker/?func=detail&atid=110894&aid=449279&group_id=10894