bug : byref on array's stil not working

[bluatigro]

see what happens :

dim a( 20 )

a( 0 ) = 1
a( 1 ) = 2

print a( 0 ) , a( 1 )
call swap a( 0 ) , a( 1 )
print a( 0 ) , a( 1 )

print "[ end byref test ]"

end
sub swap byref a , byref b
 h = a
 a = b
 b = a
end sub


[Rod]

This is not a bug IMHO. Arrays are global by default so it does not make sense to me to be passing them as parameters when calling a SUB.

Over and above that the help file is quite clear in stating that BYREF only acts on string and numeric variables. Arrays, literals and computed values are NOT supported for BYREF.

More about pass by reference
Passing by reference is only supported using string and numeric variables as parameters. You can pass a numeric or string literal, or a computed number or string, or even a value from an array, but the values will not come back from the call in any of these cases. Step through the example in the debugger to see how it works!

[B+]

sub swap byref a , byref b
h = a
a = b
b = a
end sub

Shouldn't that last line read b = h ?

[carlgundel]

It's true that support for passing elements of an array or even arrays themselves would be useful, of course. Just BASIC and Liberty BASIC do not support this language feature, but this is not a bug because it is working as designed.

Perhaps in the future this feature or something similar can be added.

[B+]

Here is a fix for bluatigro's swapping of array elements:
dim a( 20 )

a( 0 ) = 1
a( 1 ) = 2

print a( 0 ) , a( 1 )
call swapArrayElements 0 , 1
print a( 0 ) , a( 1 )

print "[ end of swap test ]"

end
sub swapArrayElements ia , ja
 h = a(ia)
 a(ia) = a(ja)
 a(ja) = h
end sub


Sure, sure we have to do this for each array we might want to swap elements with different swap subs, oh well...


Edits by Rod tidying thread.