ulis: If, for some syntax analyzis, you need to know the level of nested braces inside a list, here is a tiny proc that do that.
It returns 0 for "this is a list", 1 for "{this is a list}" or "this {is a} list", and so on.
proc listlevel {text} \
{
set count 0
set old [llength $text]
set new 0
while 1 \
{
set text [eval concat $text]
set new [llength $text]
if {$new != $old} { set old $new; incr count } \
else { break }
}
return $count
}Results:
set text "this is a list"
puts "$text: [listlevel $text]"
-> this is a list: 0
set text {this is a list}
puts "$text: [listlevel $text]"
-> this is a list: 0
set text [list this is a list]
puts "$text: [listlevel $text]"
-> this is a list: 0
set text [list "this is a list"]
puts "$text: [listlevel $text]"
-> {this is a list}: 1
set text {{this is a} list}
puts "$text: [listlevel $text]"
-> {this is a} list: 1
set text {{this {is a}} list}
puts "$text: [listlevel $text]"
-> {this {is a}} list: 2Tcl makes no difference between "this is a list" and list this is a list so I gave them the 0 level.
You can need to differentiate empty strings, one word strings and multi words strings before nested lists.