Labeled blocks

[benburrill]

Sometimes in order to get the desired control flow, it is necessary to introduce ancillary variables in Halt is Defeat that would not be needed in Sphinx. For example:

bool do_something = true;
preempt { do_something = false; }
if (do_something) {
    something();
}

Semantically equivalent Sphinx code:

j skip_something
; CALL something
skip_something:

This sort of code is fairly common, which I see as a symptom of Halt is Defeat's somewhat haphazard design / choice of abstractions, but a bandaid solution to allow for more flexible control flow would be to add labeled blocks. For the above code, this would allow:

do_something: {
    preempt { break do_something; }
    something();
}

Labeled loops should allow continue LABEL and break LABEL. Other labeled blocks should only allow break LABEL.