Keyword list - proofreading requested!

[Richard Russell]

I am not sure I see the value of the string version. Or do I miss something?

In BBC BASIC an expression can return a number or a string. An example of an expression which returns a number is '1 + 2' which returns the number '3'. An example of an expression which returns a string is '"one" + "two"' which returns the string '"onetwo"'.

EVAL passes the supplied argument to the 'expression evaluator', hence depending on that argument the expression evaluator may return a number or a string. Here's an example of when EVAL returns a number:

Code: Select all

      expression$ = "1 + 2"
      number = EVAL(expression$)

Here's an example of when EVAL returns a string:

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      expression$ = """one"" + ""two"""
      string$ = EVAL(expression$)

Of course the power of EVAL arises when the expression is somehow 'computed' at run time rather than being a literal string as in these examples, but I hope you can see why both forms are required.