Help with Subs and Functions

[JasonSG]

I was wondering if it is possible to make subs and funtions like the ones that come with qbasic:

• accepting any type for a parameter (like STR$(numeric-expression)
  
• having optional parameters (the []), using multiple sets of parenthesis and dashes (specificly the LINE function with (x,y)-(x,y))
  
• a required (or optional) charater at a certain place signifying something
  
• using an unspecifyied number of variables
  
• a parameter that must be a literal
  (the previous three are in INPUT [;] ["prompt-string"{;|,}] variablelist)
  

Thank you.

[Moneo]

The "functions" that are part of the QBasic language are not the same as a user defined function. Since they are part of the language, they can have optional parameters and other features.

No, I don't think you can get all the features that you mention in a user defined function or sub. Why would you need to do that?
*****

[JasonSG]

I've wanted to use a few of them occassionaly (specificly the optional parameters), and I was just wondering about the rest of them.

[DrV]

You can do most of that with FreeBASIC, but not with QB:

Any type of parameter: function overloading
Optional parameters: assign default value in argument list (x as integer = 3) (can't do special syntax like LINE, though)
special character: can simulate using CONST, even in QB, but otherwise not possible
Unspecified number of variables: use ... (varargs) as in C
parameter that must be a literal: I don't think any QB statement does that; not possible in FB or QB

[Macric]

for optional parameters just use a zero for an empty numerical variable and "" for an empty string

[Rattrapmax6]

With that B and BF for line, I did this:

Code:

ASCII_LINE
ASCII_LINEB
ASCII_LINEBF

Not the same, but as a lib, you could pretend they where 1 SUB when really it was 1 for each mode... lol.. :roll:

Edit: That was FB, in QB you'd need to remove the "_" from them... :wink:

[JasonSG]

Thanks. BTW, the QB sub INPUT will only except a string literal (or maybe a constant) for prompt string.