check for no type
type(x,nothing) returns false for any valid Maple expression, except an expression sequence.
Expression sequences return an error, because each element would be interpreted as a separate argument to type.
Note that one use of this type is for a local variable declaration in a procedure, and indicates that the local is to be used as-is (e.g. in an internally constructed polynomial, or as a temporary placeholder), and will not be assigned. This is helpful to avoid mint warnings for variables that are used but not assigned.
The following procedure computes a binomial coefficient and requires x be declared of type nothing to avoid a mint warning for use of an unassigned variable:
f := proc(n::posint, i::nonnegint) local pol, x::nothing; pol := expand((x+1)^n); return coeff(pol,x,i); end proc:
Download Help Document