For the full man page, see http://www.purl.org/tcl/home/man/tcl8.4/TclCmd/append.htm
NAME append - Append to variable SYNOPSIS append varName ?value value value ...? DESCRIPTION Append all of the value arguments to the current value of variable varName. If varName doesn't exist, it is given a value equal to the concatenation of all the value arguments. This command provides an efficient way to build up long variables incrementally. For example, ``append a $b'' is much more efficient than ``set a $a$b'' if $a is long.
with lists, definitely use the [concat] or [lappend] commands.
Is the result of an append of two lists a list as you might expect it? (Peter Lewerin: Yes, because append is not lappend.) (EE: Erm, NO. The result of an append of two lists is a string, which, if it can form a valid list, will shimmer into list form next time it is treated as one.)
set a [list a b c] set b [list 1 2 3] append a $b puts $a
Note that the third element of this new list is not c, but c1. Does anyone know if there are cases where an append would result in something not a list?
Here's an example of such a case:
set l1 [list a {b c}] set l2 [list {d e} f] append l1 $l2 llength $l1
RS: The intended functionality seems to me to be closer to concat. But if you wish to use append, just add an extra space to separate the parts:
append l1 " " $l2
Tcl syntax help - Arts and crafts of Tcl-tk programming - Category Command