Ramam,
you should change "upvar" to "my upvar" as in the following method
X instproc bar {ar args} { puts "bar" my upvar $ar arr puts "upvard" barray arr }
otherwise you will upvar to the filter. The plain tcl upvar is not very useful, when interceptors are added/removed dynamically.
Therefore, xotcl provides the methods "upvar" and "uplevel" to achieve interceptor transparency. This means that an upvar/uplevel refers always to the last non-interceptor method (skipping filters and mixins).
best regards -gustaf neumann
Shishir Ramam schrieb:
I am passing an array name by reference across an instproc.
The vanilla version works just fine (see creation of x1 midway through the code segment).
To add some debugging in, I essentially used the trace example from the tutorial, and funnily, the upvar stopped doing it's job (see error on creating x2 towards the end of the code segment).
To get rudimentary debug control of the parray proc, I copied it into a proc called barray. None of the logic is changed - just my crude attempt at adding breadcrumbs.
I have included the output at the end of the code segment.
Running Windows XP Pro + Active Tcl 8.4.13 + XoTcl 1.4.0.
thanks for all help. -shishir
<CODE SEGMENT> package require XOTcl namespace import ::xotcl::*
proc barray {a {pattern "*"}} { puts "barray" upvar 1 $a arr if {![array exists arr]} { error ""$a" isn't an array" } set maxl 0 foreach name [lsort [array names arr $pattern]] { if {[string length $name] > $maxl} { set maxl [string length $name] } } set maxl [expr {$maxl + [string length $a] + 2}] foreach name [lsort [array names arr $pattern]] { set nameString [format %s(%s) $a $name] puts stdout [format "%-*s = %s" $maxl $nameString $arr($name)] } }
Class X
X instproc bar {ar args} { puts "bar" upvar $ar arr puts "upvard" barray arr }
X instproc init {args} { array set arr {a 1 b 2} parray arr my bar arr }
X x1
Object Trace Trace set traceStream stdout Trace proc openTraceFile name { my set traceStream [open $name w] } Trace proc closeTraceFile {} { close $Trace::traceStream my set traceStream stdout } Trace proc puts line { puts $Trace::traceStream $line } Trace proc add className { $className instfilter [concat [$className info filter] traceFilter] }
Object instproc traceFilter args { # don't trace the Trace object if {[string equal [self] ::Trace]} {return [next]} set context "[self class]->[self callingproc]" set method [self calledproc] switch -- $method { proc - instproc {::set dargs [list [lindex $args 0] [lindex $args 1] ...] } default {::set dargs $args } } Trace::puts "CALL $context> [self]->$method $dargs" set result [next] Trace::puts "EXIT $context> [self]->$method ($result)" return $result }
Trace add X
X x2
</CODE SEGMENT>
<OUTPUT> arr(a) = 1 arr(b) = 2 bar upvard barray arr(a) = 1 arr(b) = 2 CALL ::xotcl::Object->> ::x2->cleanup EXIT ::xotcl::Object->> ::x2->cleanup () CALL ::xotcl::Object->> ::x2->configure EXIT ::xotcl::Object->> ::x2->configure (0) CALL ::xotcl::Object->> ::x2->init arr(a) = 1 arr(b) = 2 CALL ::xotcl::Object->init> ::x2->bar arr bar upvard barray "arr" isn't an array </OUTPUT>
<ERRORINFO> % set errorInfo "arr" isn't an array while executing "error "\"$a\" isn't an array"" (procedure "barray" line 5) invoked from within "barray arr" (procedure "bar" line 6) invoked from within "next" (procedure "bar" line 13) ::x2 ::xotcl::Object->traceFilter invoked from within "my bar arr" (procedure "init" line 5) invoked from within "next" (procedure "init" line 13) ::x2 ::xotcl::Object->traceFilter ::X ::xotcl::Class->recreate ::X ::xotcl::Class->create ::X ::xotcl::Class->unknown invoked from within "X x2" (file "c:/temp/trace_trouble.tcl" line 81) invoked from within "source c:/temp/trace_trouble.tcl" </ERRORINFO>
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