42.3. Data Values in PL/Tcl
The argument values supplied to a PL/Tcl function's code are simply
the input arguments converted to text form (just as if they had been
displayed by a
SELECT
statement). Conversely, the
return
and
return_next
commands will accept
any string that is acceptable input format for the function's declared
result type, or for the specified column of a composite result type.