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Full Discussion: Recursive Lists in Tcl
Top Forums Shell Programming and Scripting Recursive Lists in Tcl Post 302530009 by sarbjit on Monday 13th of June 2011 12:17:51 AM
Old 06-13-2011
Some thing like this will work as long as nested lists have more than one members.

Code:
set a {a b {c {d e}}}
proc list_eval {list_name {prefix {}}} {
set end_point [expr [llength $list_name] -1]
    for {set start_point 0} {$start_point <= $end_point} {incr start_point} {
        if {[llength [lindex $list_name $start_point]] == 1} {
            puts "Index for [lindex $list_name $start_point] is $prefix$start_point"
        } else {
            append prefix $start_point
            list_eval [lindex $list_name $start_point] $prefix
        }        
}    
}    
list_eval $a

Output will be :
Index for a is 0
Index for b is 1
Index for c is 20
Index for d is 210
Index for e is 211

---------- Post updated 06-13-11 at 09:47 AM ---------- Previous update was 06-12-11 at 04:11 PM ----------

My pvs posted code was not correct, it will not work if last members of a main list is not a part of nested list. You can use modified code.

Code:
set a {a b {c {d e} h} i}
set glob_var {}
proc list_eval {list_name {prefix {}}} {
    global glob_var
set end_point [expr [llength $list_name] -1]
    for {set start_point 0} {$start_point <= $end_point} {incr start_point} {
        if {[llength [lindex $list_name $start_point]] == 1} {
            puts "Index for [lindex $list_name $start_point] is $prefix$start_point"
           if {$start_point == $end_point} {
           set glob_var [string range $glob_var 0 end-1]
            }
        } else {
            append glob_var $start_point
            list_eval [lindex $list_name $start_point] $glob_var
       }        
}    
}    
list_eval $a

Output:
Index for a is 0
Index for b is 1
Index for c is 20
Index for d is 210
Index for e is 211
Index for h is 22
Index for i is 3
This User Gave Thanks to sarbjit For This Post:
fpmurphy
 

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LEARN ABOUT MOJAVE

lindex

lindex(n)						       Tcl Built-In Commands							 lindex(n)

__________________________________________________________________________________________________________________________________________________

NAME

       lindex - Retrieve an element from a list

SYNOPSIS

       lindex list ?index...?
_________________________________________________________________

DESCRIPTION

       The  lindex  command  accepts  a  parameter,  list, which it treats as a Tcl list. It also accepts zero or more indices into the list.  The
       indices may be presented either consecutively on the command line, or grouped in a Tcl list and presented as a single argument.

       If no indices are presented, the command takes the form:
	      lindex list
       or
	      lindex list {}
       In this case, the return value of lindex is simply the value of the list parameter.

       When presented with a single index, the lindex command treats list as a Tcl list and returns the index'th element from it (0 refers to  the
       first  element of the list).  In extracting the element, lindex observes the same rules concerning braces and quotes and backslashes as the
       Tcl command interpreter; however, variable substitution and command substitution do not occur.  If index is negative  or  greater  than	or
       equal  to  the number of elements in value, then an empty string is returned.  The interpretation of each simple index value is the same as |
       for the command string index, supporting simple index arithmetic and indices relative to the end of the list.

       If additional index arguments are supplied, then each argument is used in turn to select an element from the previous  indexing	operation,
       allowing the script to select elements from sublists.  The command,
	      lindex $a 1 2 3
       or
	      lindex $a {1 2 3}
       is synonymous with
	      lindex [lindex [lindex $a 1] 2] 3

EXAMPLES

	      lindex {a b c}
		    -> a b c
	      lindex {a b c} {}
		    -> a b c
	      lindex {a b c} 0
		    -> a
	      lindex {a b c} 2
		    -> c
	      lindex {a b c} end
		    -> c
	      lindex {a b c} end-1
		    -> b
	      lindex {{a b c} {d e f} {g h i}} 2 1
		    -> h
	      lindex {{a b c} {d e f} {g h i}} {2 1}
		    -> h
	      lindex {{{a b} {c d}} {{e f} {g h}}} 1 1 0
		    -> g
	      lindex {{{a b} {c d}} {{e f} {g h}}} {1 1 0}
		    -> g

SEE ALSO

       list(n), lappend(n), linsert(n), llength(n), lsearch(n), lset(n), lsort(n), lrange(n), lreplace(n), string(n)				   |

KEYWORDS

       element, index, list

Tcl									8.4								 lindex(n)
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