crash; can upvar support #0?

[lehenbauer]

I presume the code below coredumps because tsp upvar accepts but doesn't support #0. Would this be hard to add? We call the routine below a lot and avoid running subst on conclusionCode unless the referenced global variable is true. If analysis_subst_if could be defined as a tsp::proc and since most of the time the referenced variable is false, it seems like this tsp would be a clear performance win.

Alternatively I'm looking for a way to get the contents of a global variable inside a tsp::proc where the name of the global variable is in a variable.

package require tsp

tsp::proc analysis_subst_if {varName ident conclusionCode} {
    #tsp::procdef void -args var var var
    #tsp::int mute
    #tsp::boolean var
    #tsp::compile assert

    global mute

    if {$mute} {
        return
    }

    upvar #0 $varName var

    if {!$var} {
        return
    }

    analysis $ident [uplevel [list subst $conclusionCode]] [style_from_var $varName]
}

set var1 0
set var2 1

analysis_subst_if var1 foo "this should not emit"
analysis_subst_if var2 foo "this should emit"

[lehenbauer]

This compiles and works if the upvar target, var, is defined as a var instead of a boolean and a separate boolean var is used...

    #tsp::var var
    #tsp::boolean bool

...

    upvar #0 $varName var
    set bool $var

    if {!$bool} {
        return
    }

[lehenbauer]

Perhaps tsp should be using Tcl_UpVar to link a local obj to the correct frame and variable?