Kick Assembler Manual
Chapter 9. Scopes and Namespaces

By placing a label in front of an .if directive you can access the labels of the taken branch (true or false) of the directive. The symbol need only to be defined in the taken branch. If the condition is evaluated to false and no false branch exists, all references to symbols give an 'symbol undefined' error . Here is an example:

       jmp myIf.label

myIf: .if (true) {
         ...
label:   lda #0  // <-- Jumps here
         ...
      } else {
         ...
label:   nop
         ...
}