Delete string in file based on entry input TCL - tcl

Question

I made a simple program accepting short user inputs and storing them in a file. With another button displaying each input in the file as a button. I am trying to create another proc that deletes the button and also the string in the file when i click on the button generated by the string. How do i do that? i tried regsub on the variable holding the values but it seems to delete them once and not every time.
Code to grab current directory
catch { set abspath [file readlink [info script]]}
if { ![info exists abspath]} { set abspath $argv0 }
if { [regexp {^(\S+)\/\S+} $abspath matched dir]} { set BIN $dir }
file mkdir $BIN/debug
if {[file exists $BIN/debug/debug.txt]} { close [open $BIN/debug/debug.txt "w"]}
GUI Code
label .lbl -text "Enter something"
entry .en -justify center
button .sub -text "SUBMIT" -command "submit .en"
button .sho -text "SHOW" -command sho
button .cl -text "CLEAR" -command clear
grid .lbl -columnspan 3
grid .en -columnspan 3
grid .sub .sho .cl
Submit Procedure
proc submit {ent} {
global BIN
if {![file isdirectory $BIN/debug]} { file mkdir $BIN/debug }
set input [$ent get]
if {$input == "" || [string is space -strict $input]} {
$ent delete 0 end
.lbl configure -text "No empty strings"
} else {
set fp [open $BIN/debug/debug.txt a+]
$ent delete 0 end
puts $fp $input
close $fp
}
}
Clear Procedure
proc clear {} {
global BIN
if {[file exists $BIN/debug/debug.txt]} { close[open $BIN/debug/debug.txt "w"] }
}
Procedure to generate button for each item in file
proc sho {} {
global BIN
global filedat
set w.gui
if {[info exists filedat]} { set filedat "" }
toplevel $w
wm title "values"
wm overrideredirect $w 1
bind $w <Button-3> "destroy $w"
if {[file exists $BIN/debug/debug.txt]} {
set fp [open $BIN/debug/debug.txt r]
while {[gets $fp data] > -1} {
lappend filedat $data
}
close $fp
if {[info exist filedat]} {
set dcount 0
foreach item $filedat {
button $w.bn$dcount -text "$item" -font [list arial 10] -anchor w -fg white -bg black -command "del $item"
grid $w.bn$dcount -sticky w
incr dcount
}
} else {
label $w.nthLabel -text "Nothing in file" -bg black -fg white
grid $w.nthLabel
}
}
}
Procedure to delete string (currently not working as expected)
proc del {st} {
global filedat
regsub -all $st $filedat "" filedat2
puts $filedat2
}

Answer 1

When you delete the string with your dep proc you saved the new string in the variable filedat2.
The global variable filedat is never changed.
If you want to remove the string from your global variable, you have to pass this variable to regsub, instead of filedat2.
regsub -all $st $filedat "" filedat
Or if you prefer to save it in a temporal variable to perform some test you could use filedat2 and then assign the variable again:
regsub -all $st $filedat "" filedat2
# ... the tests
if {[isOk]} {
# update the variable
set filedat $filedat2
} else {
# leave the previous value
puts "some error here"
}