# Return Expression

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The default return value is 0 for numeric functions and "" (null) for string functions. To set another return value, assign it to the variable matching the function name (e.g. FN'name = -1). Note that this is similar in concept to the RETURN(<expression>) statement in an SBX, except that it doesn't end the function.

The return variable otherwise functions as a standard variable and can be used in expressions and be assigned a value multiple times (only the last one will matter at the time the function returns). As an example of one possibility, in the Fn'Dec2Hex\$ sample function above, the return variable Fn'Dec'Hex\$ receives its value by being passed as a parameter to a subroutine:

xcall MIAMEX, MX\_OCVT, decval, width, OT\_MEM or flags, Fn'Dec2Hex\$ 

A special case occurs when the function returns a defined structure. In this case, in order to obey the naming rules, the function name must end with a \$. But the \$ is** **dropped when referencing members of the structure. Consider this example of a function which returns an item structure when passed an item ID.

defstruct ST\_ITEM

   map2 id,s,10

   map2 descr,s,30

   map2 price,f

endstruct



map1 item,ST\_ITEM



item = Fn'Item\$("A12345")

end



Function Fn'Item\$(itemid as s10) as ST\_ITEM

   Fn'Item.id = itemid

   Fn'Item.descr = "some description"

   Fn'Item.price = 7.99

End Function



Note that the name of the function has a \$ on the end (Fn'Item\$), but when referring to the individual fields within the structure, the \$ is dropped (Fn'Item.id = itemid).

Also note that the return value of the function is a copy of the entire ST\_ITEM structure as it exists at the end of the function, even though there is no explicit reference to the structure as a whole. Any members of the structure which are not assigned would simply default to zeros or nulls, just as they would for a traditional unformatted MAP1/MAP2 structure.+

The alias .fn (or .FN or .Fn, i.e. case insensitive) may be used in place of the actual function name for the return value variable. This typically makes for easier-to-read code, and simplifies the process of changing the name of a function. Note that the alias does not take a \$ suffix, regardless of whether the function returns a number, string, or structure.  For example:

function Fn'Bracket\$(arg1 as f6) as s20

    .fn = "\[" + arg1 + "\]"    \! equivalent to Fn'Bracket\$ = ...

endfunction



**History**

2018 September, A-Shell 6.5.1647:  FN alias introduced