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