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1 This is another proof that Vim is perfectly compatible with Vi.
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2 The URM macro package was written by Rudolf Koenig ("Rudi")
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3 (rudolf@koeniglich.de) for hpux-vi in August 1991.
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4
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5 Getting started:
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6
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7 type
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8 in your shell: vim urm<RETURN>
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9 in vim: :so urm.vim<RETURN>
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10 in vim: * (to load the registers and boot the URM-machine :-)
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11 in vim: g (for 'go') and watch the fun. Per default, 3 and 4
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12 are multiplied. Watch the Program counter, it is
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13 visible as a komma moving around.
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14
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15 This is a "standard URM" (Universal register machine) interpreter. The URM
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16 concept is used in theoretical computer science to aid in theorem proving.
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17 Here it proves that vim is a general problem solver (if you bring enough
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18 patience).
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19
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20 The interpreter begins with register 1 (not 0), without macros and more-lines
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21 capability. A dot marks the end of a program. (Bug: there must be a space
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22 after the dot.)
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23
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24 The registers are the first few lines, beginning with a '>' .
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25 The program is the first line after the registers.
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26 You should always initialize the registers required by the program.
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27
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28 Output register: line 2
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29 Input registers: line 2 to ...
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30
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31 Commands:
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32 a<n> increment register <n>
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33 s<n> decrement register <n>
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34 <x>;<y> execute command <x> and then <y>
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35 (<x>)<n> execute command <x> while register <n> is nonzero
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36 . ("dot blank") halt the machine.
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37
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38 Examples:
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39
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40 Add register 2 to register 3:
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41 (a2;s3)3.
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42 Multiply register 2 with register 3:
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43 (a4;a5;s2)2; ((a2;s4)4; s3; (a1;a4;s5)5; (a5;s1)1)3.
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44
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45 There are more (complicated) examples in the file examples.
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46 Note, undo may take a while after a division.
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47
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