vi-turing - vi is Turing complete!
vi-turing is a Turing Machine interpreter written in form of vi keyboard macros. This proves that - given enough scratch space - vi macros are Turing complete!
Usage
- Open vi-turing.vi in your favorite vi (ex-vi, nvi, elvis, vim are currently supported).
- Load vi-turing.vi's macros:
ESC :source % RETURN - Initialize:
\I - Run:
\\
Lessons learned
The following quirks of different vi versions were encountered during development of this:
- In ex-vi, you cannot yank from within a nontrivial macro. Example:
:map \a yl,:map \\ \ap-> beep, "p" will not paste anything. - In ex-vi, you cannot paste from any register other than the default one
from within a macro. Example:
:map \\ "ayl"ap-> "Can't put partial line inside macro". - In elvis,
@@only executes unnamed registers."ayl@@does not work there. - In ex-vi, you cannot use marks from within a nontrivial macro.
- vi implementations do not agree on where the cursor is put after pasting
from a register.
- ex-vi: last character of the paste.
- nvi: first character of the paste.
- elvis: last character of the paste.
- vim: last character of the paste.