In [Tcl], to ''listify'' a string is the process the interpreter goes through to create a list object whose contents are in a [list] safe form.

The [split] command can be used by a script to force the change.

''[Lars H] thinks the above is under-specified to such a degree that it is meaningless, and most definitely confusing. It is true that [split] always returns a list, but that doesn't mean it is some universal listification operation, or even that the idea of such a thing makes sense. Every string->list operation makes some sort of '''interpretation''' of the string, and it is generally that interpretation one should focus on specifying, not just wanted input and output datatypes. [split] applies one interpretation which is sometimes appropriate, and other times quite wrong. It is in particular rather far from preserving input that is already a list, which might be one requirement for a [listify] operation.''

An example (based on some comments left on the [lset] page) of listification of a Tcl variable is:
======
% set l "    a    b    c }   d   "
    a    b    c }   d   
% lset l 1 a
a a c \} d
% lindex $l 2
c
% puts $l
a a c \} d
======

Notice that leading spaces are gone, internal spaces are collapsed into 1, and the right brace is quoted.

Also, note that strings with certain characters can result in errors rather than listification:

======
% set l "  a  b     c    }  d { e "
  a  b     c    }  d { e 
% lset l 0 "  a"
unmatched open brace in list
======

Using [split] to force the listification results in completion of the task:
======
% set l "  a  b     c    }  d { e "
  a  b     c    }  d { e 
% set a [split $l]
{} {} a {} b {} {} {} {} c {} {} {} \} {} d \{ e {}
% lset a 0 "  a"
{  a} {} a {} b {} {} {} {} c {} {} {} \} {} d \{ e {}
======

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