From Newsgroup: comp.lang.tcl

I want to pass a bound method to fileutil::traverse as a -prefilter.
I'm using `lambda` but it doesn't help. I can't work out what I'm
doing wrong based on the error output.

Below is a cut-down version of the code, followed by the error output.
To test it run as, say, `tclsh9 find.txt /tmp`

### Code

package require fileutil::traverse
package require lambda 1
package require textutil

proc main {} {
set config [Config new]
$config folders $::argv
process $config
}

proc process config {
set pre_filter [lambda {ignore dirname} {
dir_filter $ignore $dirname
} [$config ignore]]
foreach dir [$config folders] {
fileutil::traverse iter -prefilter $pre_filter
$iter foreach filename {
puts $filename
}
$iter destroy
}
puts [$config to_string] ;# TODO delete
}

proc dir_filter {ignores dirname} {
for ignore $ignores {
if {[string match -nocase $ignore $dirname]} { return false }
}
return true
}

oo::class create Config {
variable Ignore
variable What
variable Folders
}

oo::define Config constructor {} {
set Ignore [list test*.* zOld]
set What ".tcl"
set Folders [list]
}

oo::define Config method ignore {{ignore ""}} {
if {$ignore ne ""} { set Ignore $ignore }
return $Ignore
}

oo::define Config method what {{what ""}} {
if {$what ne ""} { set What $what }
return $What
}

oo::define Config method folders {{folders ""}} {
if {$folders ne ""} { set Folders $folders }
return $Folders
}

oo::define Config method to_string {} {
return "Config Ignore=$Ignore What=$What Folders=$Folders"
}

main

### Error

$ ./find.tcl /tmp/
unknown option "::apply {{ignore dirname} {
dir_filter $ignore $dirname
}} {test*.* zOld}"
while executing
"$self configurelist $args"
(procedure "::fileutil::traverse::Snit_constructor" line 6)
invoked from within
"::fileutil::traverse::Snit_constructor ::fileutil::traverse ::fileutil::traverse::Snit_inst1 ::iter ::iter -prefilter {::apply {{ignore dirname} {
..."
("eval" body line 1)
invoked from within
"eval [linsert $arglist 0 ${type}::Snit_constructor $type $selfns $instance $instance]"
(procedure "RT.ConstructInstance" line 9)
invoked from within
"RT.ConstructInstance $type $selfns $name $args"
(procedure "::snit::RT.type.typemethod.create" line 45)
invoked from within
"fileutil::traverse iter -prefilter $pre_filter"
(procedure "process" line 6)
invoked from within
"process $config"
(procedure "main" line 4)
invoked from within
"main"
(file "./find.tcl" line 66)
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From Newsgroup: comp.lang.tcl

* Mark Summerfield <m.n.summerfield@gmail.com>
| I want to pass a bound method to fileutil::traverse as a -prefilter.
| I'm using `lambda` but it doesn't help. I can't work out what I'm
| doing wrong based on the error output.
--<snip-snip>--
| fileutil::traverse iter -prefilter $pre_filter
--<snip-snip>--
| unknown option "::apply {{ignore dirname} {
| dir_filter $ignore $dirname
| }} {test*.* zOld}"

man traverse(n)
::fileutil::traverse ?objectName? path ?option value...?

I think you are missing the PATH argument to ::fileutil::traverse, so
the '-prefilter' is taken as the path, and the $pre_filter as an option
name (which does not exist, as the error message states :-)

R'
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From Newsgroup: comp.lang.tcl

* Mark Summerfield <m.n.summerfield@gmail.com>
| proc dir_filter {ignores dirname} {
| for ignore $ignores {

Also make this a 'foreach' instead.

R'
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From Newsgroup: comp.lang.tcl

On Wed, 23 Jul 2025 11:11:39 -0000 (UTC), Mark Summerfield wrote:

I want to pass a bound method to fileutil::traverse as a -prefilter.
I'm using `lambda` but it doesn't help. I can't work out what I'm
doing wrong based on the error output.

Below is a cut-down version of the code, followed by the error output.
To test it run as, say, `tclsh9 find.txt /tmp`

### Code

package require fileutil::traverse
package require lambda 1
package require textutil

proc main {} {
set config [Config new]
$config folders $::argv
process $config
}

proc process config {
set pre_filter [lambda {ignore dirname} {
dir_filter $ignore $dirname
} [$config ignore]]
foreach dir [$config folders] {
fileutil::traverse iter -prefilter $pre_filter
$iter foreach filename {
puts $filename
}
$iter destroy
}
puts [$config to_string] ;# TODO delete
}

proc dir_filter {ignores dirname} {
for ignore $ignores {
if {[string match -nocase $ignore $dirname]} { return false }
}
return true
}

oo::class create Config {
variable Ignore
variable What
variable Folders
}

oo::define Config constructor {} {
set Ignore [list test*.* zOld]
set What ".tcl"
set Folders [list]
}

oo::define Config method ignore {{ignore ""}} {
if {$ignore ne ""} { set Ignore $ignore }
return $Ignore
}

oo::define Config method what {{what ""}} {
if {$what ne ""} { set What $what }
return $What
}

oo::define Config method folders {{folders ""}} {
if {$folders ne ""} { set Folders $folders }
return $Folders
}

oo::define Config method to_string {} {
return "Config Ignore=$Ignore What=$What Folders=$Folders"
}

main

### Error

$ ./find.tcl /tmp/
unknown option "::apply {{ignore dirname} {
dir_filter $ignore $dirname
}} {test*.* zOld}"
while executing
"$self configurelist $args"
(procedure "::fileutil::traverse::Snit_constructor" line 6)
invoked from within
"::fileutil::traverse::Snit_constructor ::fileutil::traverse ::fileutil::traverse::Snit_inst1 ::iter ::iter -prefilter {::apply {{ignore dirname} {
..."
("eval" body line 1)
invoked from within
"eval [linsert $arglist 0 ${type}::Snit_constructor $type $selfns $instance $instance]"
(procedure "RT.ConstructInstance" line 9)
invoked from within
"RT.ConstructInstance $type $selfns $name $args"
(procedure "::snit::RT.type.typemethod.create" line 45)
invoked from within
"fileutil::traverse iter -prefilter $pre_filter"
(procedure "process" line 6)
invoked from within
"process $config"
(procedure "main" line 4)
invoked from within
"main"
(file "./find.tcl" line 66)

I solved it myself eventually.

proc process config {
set pre_filter [lambda {foldcase ignore dirname} {
dir_filter $foldcase $ignore $dirname
} [$config foldcase] [$config ignore]]
foreach dir [$config folders] {
fileutil::traverse iter $dir -prefilter $pre_filter
iter foreach filename {
puts $filename
}
iter destroy
}
puts [$config to_string] ;# TODO delete
}

I'd made two mistakes, (1) forgot to put in the $dir arg;
(2) used $iter instead of iter.
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