print all global variable values
Patrick
it but I am still struggling with it. I am trying to print all global
variables and their values at a certain point in execution.
Here's what I have:
proc print_globals {} {
foreach name [info globals] {
global $name
puts "$name -> $$name"
}
}
the output of which I am trying to get to be
...
tcl_version -> 8.5
...
but here's what's actually occurring
tcl_version -> $tcl_version
I know I am overlooking something simple. A little help??
David Bariod
wrote:
> I am trying to do something that seemed so simple when I decided to do
> it but I am still struggling with it. I am trying to print all global
> variables and their values at a certain point in execution.
>
> Here's what I have:
>
> proc print_globals {} {
> foreach name [info globals] {
> global $name
> puts "$name -> $$name"
> }
>
> }
>
The $variable_name is a short cut for
set variable_name
Two consecutive $ does not work.
You shoud use:
puts "$name -> [set $name]"
which is completely equivalent to
puts "[set name] -> [set [set name]]"
David Bariod
Patrick
future reference:
proc print_globals {} {
foreach name [info globals] {
global $name
if [array exists $name] {
parray $name
} else {
puts "$name = [set $name]"
}
}
}
Bezoar
wrote:
this would also work
eval puts \"$name = \$$name\"
Carl
Jonathan Bromley
> proc print_globals {} {
> foreach name [info globals] {
> global $name
> if [array exists $name] {
> parray $name
> } else {
> puts "$name = [set $name]"
> }
> }
> }
The [upvar] command neatly combines making a global
reference with providing a convenient local alias.
proc print_globals {{pattern *}} {
foreach name [info globals $pattern] {
upvar #0 $name v
if {[array exists v]} {
parray v
} else {
puts "$name = $v"
}
}
}
This also could very easily be modified to
print variables in the calling, rather than the
global, scope (just use "upvar 1" instead of
"upvar #0"). Finally, the use of a match-pattern
that defaults to "*" gives a better parallel with
the behaviour of "info vars" and "info global".
hth
--
Jonathan Bromley
David Bariod
>
> this would also work
>
> eval puts \"$name = \$$name\"
This will not always work.
If your variable name contains space, it will fail.
Of course that is not a common usage to have space in
variable name but it is totally legal.
David Bariod
Donal K. Fellows
wrote:
> I am trying to do something that seemed so simple when I decided to do
> it but I am still struggling with it. I am trying to print all global
> variables and their values at a certain point in execution.
>
> Here's what I have:
>
> proc print_globals {} {
> foreach name [info globals] {
> global $name
> puts "$name -> $$name"
> }
> }
That will go badly wrong if you have any global variables called
'name', you know? Try this one instead:
proc printGlobals {} {
foreach name [info globals] {
upvar #0 $name var
if {![info exist var]} continue; # Skip some awkward cases
if {[array exists var]} {
# This is a bit of cheat for printing an array...
uplevel #0 [list parray $name]
} else {
puts "$name -> $var"
}
}
}
Works when I try it (but produces rather more output than I care to
list here...)
> I know I am overlooking something simple. A little help??
Your problem was that $$ does not do double-dereferencing. You could
have tried with [set $name] instead, but that is still not as good as
the alternative I posted.
Donal.
tom.rmadilo
<donal.k.fell...@manchester.ac.uk> wrote:
> upvar #0 $name var
> if {![info exist var]} continue; # Skip some awkwar
Hmmm, so there are cases where globals show up in [info globals] but
don't yet have a value? I know this is the case with namespaced
variables, but couldn't reproduce with the equivalent [global myvar]
command.
Anyway, good to know.
Here's what I use in my "inspect" (code browser) package:
proc ::quotehtml { html } {
return [string map {< < > > & &} $html]
}
proc ::inspect::findVars { namespace {pattern *}} {
return [lsort [info vars ${namespace}::$pattern]]
}
proc ::inspect::displayVars { {namespace ::} {pattern *} } {
set vars [::inspect::findVars $namespace $pattern]
set output "
<h4> Variables in $namespace</h4>
<pre>
"
foreach var $vars {
if {[array exists $var]} {
set arrayNames [array names $var]
append output "Array [quotehtml $var]\n"
foreach arrayName $arrayNames {
append output " [quotehtml ${var}\($arrayName\)] =
'[quotehtml [set ${var}($arrayName)]]'\n"
}
} elseif {[info exists $var]} {
append output " [quotehtml $var] = '[quotehtml [set $var]]'\n"
} else {
append output " [quotehtml $var] is currently undefined\n"
}
}
append output "</pre>\n"
return $output
}
By default this works on the global namespace and avoids the use of
[upvar].
Donal K. Fellows
> Hmmm, so there are cases where globals show up in [info globals] but
> don't yet have a value? I know this is the case with namespaced
> variables, but couldn't reproduce with the equivalent [global myvar]
> command.
Yes, when there are traces attached to an unset global variable (or
you've done certain very ugly things with [upvar]). This results in
the variable having an entry in the table of variables, but still
being marked as 'not existing'.
Donal.