Full BASIC is a language that is defined to check for grammatical errors before starting execution.
It is not possible to rewrite a running program by itself or from outside.
However, Decimal BASIC allows you to specify a program before it is compiled as the link destination of a CHAIN statement, so it is possible to use a trick to transfer control to a program that you have output.
Details
Using external programs
Sometimes you may want to define a function I(f,a,b) that finds the value of the definite integral of a function f(x) over the interval [a,b], but in Full BASIC, functions cannot be used as arguments to other procedures. In other words, f cannot be specified while a program is running.
Unlike interpreter-type BASIC such as N88BASIC, you cannot write multiple DEF statements for the same function name so that the function definition changes as the program is executed.
All you can do in Full BASIC is to specify function parameters as variables. For example,，
DEF f(x) = a*x^3 + b*x^2 + c*x + d
It is possible to change the values of a, b, c, and d at runtime by writing like above.
BASIC does not have a function to find the derivative as a function. Therefore, when writing a program to find the zeros of a function using Newton's method, for example,
DEF f(x) = a*x^3 + b*x^2 + c*x + d DEF g(x) = 3*a*x^2 + 2*b*x +c
As shown above, the derivative must be written in the program along with the original function.
It is possible
to create a function that returns the derivative in the form of a string when a composite function of functions within the range defined as built-in functions in Full BASIC is given in the form of a string, but there is no way to use this in a program.
If you really want to do this, you will need a secret technique to write out the program and execute it.
Full BASIC does not have a mechanism to directly handle computer memory.
Structure types (structures, record types, etc.)
Full BASIC has no concepts equivalent to Visual BASIC's user-defined types, C language structures, or Pascal's record types.
Pointers
Full BASIC does not have pointers. To implement algorithms that use pointers to create link structures, Full BASIC uses arrays and subscripts instead of pointers.