Why are you debating the validity of the argument?
The code very clearly:
- is an implementation of the halting problem. If halt existed it would undoubtly solve the halting problem
- it uses '+'
You are prentending I didn't know what the author meant. The point is that what the author says is simply not true, if you take the statement as written.
What he wants to show is that if canBeRegex is computable then halt is computable, but that isn't what he is saying.
The code very clearly:
- is an implementation of the halting problem. If halt existed it would undoubtly solve the halting problem
- it uses '+'
You are prentending I didn't know what the author meant. The point is that what the author says is simply not true, if you take the statement as written. What he wants to show is that if canBeRegex is computable then halt is computable, but that isn't what he is saying.