Testing strings

The following string operators, discussed in greater detail in §21.11, may be used in equations:

empty$()

to test whether or not a string is empty.

eq$(,)

to test the equality of two strings.

len$()

to return the length of a string.

neq$(,)

to test the inequality of two strings.

real$()

to test whether a string represents in integer; a real number; or neither of these.

These string operators all return the value unity if the test is true, and zero otherwise, and all may be used in equations in the usual way.