Atari ST GFA basic : what do variable suffixes correspond to?

Question

I'm dusting off my Atari ST 520, and am trying to understand some semantic details of the GFA basic. The TYPE(ptr) function is documented this way :

     Determines the type of the variable at which a pointer
       is set.

       'ptr' is an integer expression (usually *var).
       TYPE(ptr) returns a code according to the type of
       variable to which 'ptr' is pointing.
           0=var  
           1=var$  
           2=var%  
           3=var!  
           4=var()  
           5=var$()
           6=var%()  
           7=var!()

The same documentation does not talk about what these suffixes mean. (It must be so obvious)

I seem to recall that $ is a string/memory block, % an integer, () an array of the same. What are ! and nothing? ! seems to be used for 0/1 variables.

score 7 · Accepted Answer · answered Mar 04 '14 at 14:43

7

That's correct $ string, % integer, ! boolean , and nothing (0) is double.

http://www.atari-forum.com/wiki/index.php?title=GFAvariablestutorial

answered Mar 04 '14 at 14:43

Jimmy Smith

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score 1 · Answer 2 · answered Aug 25 '20 at 14:47

The final version of the manual states:

Boolean  !  1 byte (1 bit in arrays)  0 or -1 (FALSE or TRUE)
Byte     |  1 byte                    0 to 255
Word     &  2 bytes                   -32768 to 32767
Long     %  4 bytes                   -2147483648 to 2147483647
Float    #  8 bytes                   2.225073858507E-308 to 3.595386269725E+308
String   $  0 to 32767 bytes          ASCII value 0 to 255 for each character

The default variable type doesn't display a suffix and can be changed.

Thank you for your answer. I see that the list you provided includes `#` for `Float`. What is the documentation for `TYPE(ptr)`, in the same version of the manual? — Laurent LA RIZZA, Jul 07 '21 at 09:14

Atari ST GFA basic : what do variable suffixes correspond to?

2 Answers2