Iteration operators let you cause certain expressions to be evaluated repeatedly. For example, the FOR-EACH operator takes two arguments: a variable and a sequence. The expressions within it will be evaluated once with the variable set to each element of the sequence.
A string is one kind of sequence. For example, this template
will generate a page containing the letters a through g on separate lines.Letters () TITLE "A B C..." BODY FOR-EACH variable letter sequence "abcdefg" TEXT letter LINEBREAK
In English, it says: for each letter in "abcdefg", display that letter followed by a linebreak.