Retro1.org codex

&CONCAT FUNCTION                                         EXEC built-in function

Use the &CONCAT function to concatenate two or more tokens and assign the
result to a variable symbol.  The format of the &CONCAT function is:
+-----------+-----------------------------------------------------------------+
| &CONCAT   | tok1 [tok2 ... [tokn]]                                          |
+-----------+-----------------------------------------------------------------+
where:

tok1 [tok2 ... [tokn]]
         specifies the tokens that are to be concatenated into a single token,
         with a maximum length of eight characters.  This function is valid
         only on the right-hand side of an assignment statement.  For example:
            &A = **
            ...
            &B = &CONCAT XX &A 45
            &TYPE &B

         results in the printed line:
            XX**45

         If the concatenated token is longer than eight characters, the data
         are left-justified and truncated on the right.