Handle variables do not work with RANDOM files

Description

The Liberty BASIC help file states that "In versions of Liberty BASIC prior to version 4, the manipulation of files and windows was done using statically declared handles for each file, window or GUI control. Now you can create more reusable code because handle variables allow you to pass a handle using a string form".

There is no indication that this will not work with random files but in practice the FIELD, GET and PUT statements do not accept handle variables. This is potentially quite serious because it makes it impossible to incorporate those statements in a reusable function, to which the file handle is passed as a parameter.

Example code to demonstrate the bug.

    handle$ = "#myHandle"
    open "test.raf" for random as #1 len = 20
    maphandle #1, handle$
    field #handle$, 6 as field1, 14 as field2
    put #handle$, 1
    close #handle$

This code should work, but in LB 4.04 and LB 4.5.0 the runtime error "Undefined handle: #handle$" is reported.