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- This is another proof that Vim is perfectly compatible with Vi.
- The URM macro package was written by Rudolf Koenig ("Rudi")
- (rudolf@koeniglich.de) for hpux-vi in August 1991.
- Getting started:
- type
- in your shell: vim urm<RETURN>
- in vim: :so urm.vim<RETURN>
- in vim: * (to load the registers and boot the URM-machine :-)
- in vim: g (for 'go') and watch the fun. Per default, 3 and 4
- are multiplied. Watch the Program counter, it is
- visible as a komma moving around.
- This is a "standard URM" (Universal register machine) interpreter. The URM
- concept is used in theoretical computer science to aid in theorem proving.
- Here it proves that vim is a general problem solver (if you bring enough
- patience).
- The interpreter begins with register 1 (not 0), without macros and more-lines
- capability. A dot marks the end of a program. (Bug: there must be a space
- after the dot.)
- The registers are the first few lines, beginning with a '>' .
- The program is the first line after the registers.
- You should always initialize the registers required by the program.
- Output register: line 2
- Input registers: line 2 to ...
- Commands:
- a<n> increment register <n>
- s<n> decrement register <n>
- <x>;<y> execute command <x> and then <y>
- (<x>)<n> execute command <x> while register <n> is nonzero
- . ("dot blank") halt the machine.
- Examples:
- Add register 2 to register 3:
- (a2;s3)3.
- Multiply register 2 with register 3:
- (a4;a5;s2)2; ((a2;s4)4; s3; (a1;a4;s5)5; (a5;s1)1)3.
- There are more (complicated) examples in the file examples.
- Note, undo may take a while after a division.
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