Quick Gist of the paradox we are trying to prevent in our assembly

if-label-paradox.md

The "If-Label" Paradox

In our assembly we are implementing the support for conditional translation:

%include "natives.hasm"
%const N 10
main:
    push 1
    push 2
    push 3
    %if N < 69
        drop
        drop
        drop
    %end
    halt

If N < 69 is true the block of 3 drop-s will be included in the final executable, otherwise it will not.

The problem occurs when we have the following situation:

%include "natives.hasm"
%const N 10
main:
    push 1
    push 2
    push 3
    %if end < 69
        drop
        drop
        drop
    %end
end:
    halt

The condition depends on the value of end, but the value of end depends on whether the block above it is included. This creates a paradox that we must detect at translation time and report to the user approriately with hints on how to resolve it.