re: DEF FN & subscripts

[bitvast]

Just checking - it seems that DEF FN returns a float by default, so the only subscript necessary is $ for strings?

[bigbass]

this is the normal standardized way in the docs
DEF FN First$(x$) = LEFT$(x$, INSTR(x$, " ")-1)
PRINT First$("One Two Three")


however this below is a non-standard but a needed way also
focus attention on the $ after First not being used
*That's nice because it keeps it BaConized using BaCon's syntax
and solving the big problem of when you have to port c macros (that never use the $)

DEF FN First(x$) = LEFT$(x$, INSTR(x$, " ")-1)
PRINT First("One Two Three") FORMAT "%s\n"

Well its good that there are several ways to get a result
Maybe we could add these too as "special extra options" for with and without the $

Joe

[bitvast]

Hi Joe,


FUNCTION area1(FLOATING x, FLOATING y)
  RETURN x * y
END FUNCTION

DEF FN area2(x, y) = x * y

PRINT area1(2.5, 3)
PRINT area2(2.5, 3)
7
7.5

Adding the float subscript # to area1 results in 7.5, but the DEF FN function doesn't need it.

[Pjot]

Hi bitvast,

The difference is that DEF FN is actually being replaced by the 'x*y', while the function returns a value.

Be
Peter

[bigbass]

Using the DEF FN is another approach
bacons way of macros (the syntax is different so be careful)

gcc.gnu.org/onlinedocs/cpp/Macros.html

www.cprogramming.com/tutorial/cpreprocessor.html

Macros
The other major use of the preprocessor is to define macros. The advantage of a macro is that it can be type-neutral (this can also be a disadvantage, of course), and it's inlined directly into the code, so there isn't any function call overhead.


Functions are generally better to use because they are easier to debug if something goes wrong


If interested in how to convert them to bacon
basic-converter.proboards.com/thread/518/macro-define-bacon-def-fn

[bigbass]

Hey bitvast


Maybe I posted too much info
in the last post looking back but there are many differences
between FUNCTION and DEF FN better to think DEF FN is a preprocessed macro
that doesn't need the type to be given

so just to solve your original question

here is just the working solution
notice we added a return TYPE FLOATING
then you can decide how you want to format the output
I used %.1f to allow one decimal place to display

Hope that answer is to the point
Joe

FUNCTION area1(FLOATING x, FLOATING y) TYPE FLOATING
RETURN x * y
END FUNCTION

DEF FN area2(x, y) = x * y

PRINT area1(2.5, 3) FORMAT "%.1f\n"
PRINT area2(2.5, 3)

7.5
7.5

[bitvast]

Hi Joe, I didn't realize that DEF FN uses C macros, just been reading up about them, now I understand.

Or you can use the subscript way:


FUNCTION area1#(FLOATING x, FLOATING y)
 RETURN x * y
END FUNCTION

DEF FN area2(x, y) = x * y

PRINT area1#(2.5, 3) FORMAT "%.1f\n"
PRINT area2(2.5, 3)