'''`[ycl] string expand`'''  is a [Template and Macro processing%|%macro
system] that replaces substrings in a string by iteratively replacing lists
nested in a substring itself with items from the list.  The idea is to keep the
source code readable while minimizing literal repetition.

======
set a {one two three}
set b {four five six}
if 1 [expand {
    [@
        foreach list [* $a $b *] {
            foreach item $list {
                lappend res $item
            }
        }
    @]
}]
set res ;# -> {one two three four five six}
======




<<categories>> ycl