The makeparam and makeglobal functions are used to make a variable to be a parameter, respectively global variable in the Maple procedure. If a list of variables is given, then all the variables in the list are made into parameters, respectively globals.

If a type t is specified the variable is given the specified type.  This can be used to declare the type of a variable.

The declare function is used to specify the type t for a variable x which is a parameter in the Maple procedure f.

f := proc() local A; A := array(1..2); A[1] := x^2; A[2] := x^2; A end proc: